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Purpose: To survey elite athletes and practitioners to identify (1) knowledge and application of heat acclimation/acclimatization (HA) interventions, (2) barriers to HA application, and (3) nutritional practices supporting HA. Methods: Elite athletes (n = 55) and practitioners (n = 99) completed an online survey. Mann–Whitney U tests (effect size [ES; r]) assessed differences between ROLE (athletes vs practitioners) and CLIMATE (hot vs temperate). Logistic regression and Pearson chi-square (ES Phi [ϕ]) assessed relationships. Results: Practitioners were more likely to report measuring athletes’ core temperature (training: practitioners 40% [athletes 15%]; P = .001, odds ratio = 4.0, 95% CI, 2%–9%; competition: practitioners 25% [athletes 9%]; P = .020, odds ratio = 3.4, 95% CI, 1%–10%). Practitioners (55% [15% athletes]) were more likely to perceive rectal as the gold standard core temperature measurement site (P = .013, ϕ = .49, medium ES). Temperate (57% [22% hot]) CLIMATE dwellers ranked active HA effectiveness higher (P r = .30, medium ES). Practitioners commonly identified athletes’ preference (48%), accessibility, and cost (both 47%) as barriers to HA. Increasing carbohydrate intake when training in the heat was more likely recommended by practitioners (49%) than adopted by athletes (26%; P = .006, 95% CI, 0.1%–1%). Practitioners (56% [28% athletes]) were more likely to plan athletes’ daily fluid strategies, adopting a preplanned approach (P = .001; 95% CI, 0.1%–1%). Conclusions: Practitioners, and to a greater extent athletes, lacked self-reported key HA knowledge (eg, core temperature assessment/monitoring methods) yet demonstrated comparatively more appropriate nutritional practices (eg, hydration).

This systematic review analyzed whether carbohydrate source (food vs. supplement) influenced performance and gastrointestinal (GI) symptoms during endurance exercise. Medline, SPORTDiscus, and citations were searched from inception to July 2021. Inclusion criteria were healthy, active males and females aged >18 years, investigating endurance performance, and GI symptoms after ingestion of carbohydrate from a food or supplement, n = 1) or cycling (n = 13) performance/capacity between food and supplemental sources. Greater GI symptoms were reported with food compared with supplemental sources. Highly heterogenous study designs for carbohydrate dose and timing, as well as exercise protocol and duration, make it difficult to compare findings between studies. A further limitation results from only one study assessing running performance. Food choices of carbohydrate consumed immediately before and during endurance exercise result in similar exercise performance/capacity responses to supplemental carbohydrate sources, but may slightly increase GI symptoms in some athletes, particularly with exercise >2 hr.

Short-term dietary nitrate (NO3−) supplementation has the potential to enhance performance during submaximal endurance, and short-duration, maximal-intensity exercise. However, it has yet to be determined whether NO3− supplementation before and during submaximal endurance exercise can improve performance during a short-duration, maximal-intensity end-sprint. In a randomised, double-blind, crossover study, 9 recreationally active men ingested NO3−-rich (BR: 8 mmol NO3−/day) and NO3−-depleted (PL: 0.75 mmol NO3−/day) beetroot powder for 7 days. On day 7, participants completed 2 h of moderate-intensity cycling, which immediately transitioned into a 60 s maximal-intensity end-sprint, with supplements ingested 2 h before and 1 h into the moderate-intensity exercise bout. Plasma [NO3−] and [NO2−] were higher in BR compared to PL pre- and post-exercise (p < 0.05). Post-exercise plasma [NO3−] was higher than pre-exercise (562 ± 89 µM vs. 300 ± 73 µM; p < 0.05) and plasma [NO2−] was not significantly different pre- (280 ± 58 nM) and post-exercise (228 ± 63 nM) in the BR condition (p > 0.05). Mean power output during the final 30 s of the end-sprint was greater after BR (390 ± 38 W) compared to PL (365 ± 41 W; p < 0.05). There were no differences between BR and PL in any muscle oxygenation variables during moderate-intensity cycling (p > 0.05), but muscle [deoxyhaemoglobin] kinetics was faster during the end-sprint in BR (6.5 ± 1.4 s) compared to PL (7.3 ± 1.4 s; p < 0.05). These findings suggest that NO3− supplementation has the potential to improve end-sprint performance in endurance events when ingested prior to and during exercise.

Bioactive collagen peptides (CP) have been suggested to augment the functional, structural (size and architecture), and contractile adaptations of skeletal muscle to resistance training (RT), but with limited evidence. This study aimed to determine if CP vs. placebo (PLA) supplementation enhanced the functional and underpinning structural, and contractile adaptations after 15 weeks of lower body RT.Young healthy males were randomized to consume either 15 g of CP (n = 19) or PLA (n = 20) once every day during a standardized program of progressive knee extensor, knee flexor, and hip extensor RT 3 times/wk. Measurements pre- and post-RT included: knee extensor and flexor isometric strength; quadriceps, hamstrings, and gluteus maximus volume with MRI; evoked twitch contractions, 1RM lifting strength, and architecture (with ultrasound) of the quadriceps.Percentage changes in maximum strength (isometric or 1RM) did not differ between-groups (0.684 ≤ p ≤ 0.929). Increases in muscle volume were greater (quadriceps 15.2% vs. 10.3%; vastus medialis (VM) 15.6% vs. 9.7%; total muscle volume 15.7% vs. 11.4%; [all] p ≤ 0.032) or tended to be greater (hamstring 16.5% vs. 12.8%; gluteus maximus 16.6% vs. 12.9%; 0.089 ≤ p ≤ 0.091) for CP vs. PLA. There were also greater increases in twitch peak torque (22.3% vs. 12.3%; p = 0.038) and angle of pennation of the VM (16.8% vs. 5.8%, p = 0.046), but not other muscles, for CP vs. PLA.CP supplementation produced a cluster of consistent effects indicating greater skeletal muscle remodeling with RT compared to PLA. Notably, CP supplementation amplified the quadriceps and total muscle volume increases induced by RT.

Acute morning fasted exercise may create a greater negative 24-hr energy balance than the same exercise performed after a meal, but research exploring fasted evening exercise is limited. This study assessed the effects of 7-hr fasting before evening exercise on energy intake, metabolism, and performance. Sixteen healthy males and females (n = 8 each) completed two randomized, counterbalanced trials. Participants consumed a standardized breakfast (08:30) and lunch (11:30). Two hours before exercise (16:30), participants consumed a meal (543 ± 86 kcal; FED) or remained fasted (FAST). Exercise involved 30-min cycling (∼60% VO2peak) and a 15-min performance test (∼85% VO2peak; 18:30). Ad libitum energy intake was assessed 15 min postexercise. Subjective appetite was measured throughout. Energy intake was 99 ± 162 kcal greater postexercise (p p p p ≥ .458). Fat oxidation was greater (+3.25 ± 1.99 g), and carbohydrate oxidation was lower (−9.16 ± 5.80 g) during exercise in FAST (p p p

Carbohydrate consumption during exercise enhances endurance performance. A food-focused approach may offer an alternative, ‘healthier’ approach given the potential health concerns associated with artificial fructose sources, but food-based carbohydrate sources may increase gastrointestinal (GI) symptoms. This study compared the cycling performance and GI comfort of two different fructose sources (fruit and artificial) ingested during exercise. Nine trained male cyclists (age 24 ± 7 years; VO2peak 65 ± 6 mL/kg/min) completed a familiarisation and two experimental trials (60 g/h carbohydrate, 120 min at 55% Wmax and ~15 min time trial). In the two experimental trials, carbohydrate was ingested in a 2:1 glucose-to-fructose ratio, with fructose provided as artificial crystalline fructose (GLU/FRU) or natural apple puree (APPLE PUREE) and maltodextrin added to provide sufficient glucose. Time trial (TT) performance was not different between trials (GLU/FRU 792 ± 68 s, APPLE PUREE 800 ± 65 s; p = 0.313). No GI symptoms were significantly different between trials (p ≥ 0.085). Heart rate, blood glucose/lactate concentrations, and RPE were not different between trials, but all, excluding blood glucose concentration, increased from rest to exercise and further increased post-TT. Apple puree as a natural fructose source provides an alternative to artificial fructose sources without influencing cycling performance or GI symptoms.

Exercise is an important component of a weight management strategy. However, little is known about whether circadian variations in physiological and behavioural processes can influence the appetite and energy balance responses to exercise performed at different times of the day. This study compared the effects of morning and evening exercise on appetite, post-exercise energy intake, and voluntary performance. In randomised, counterbalanced order, 16 healthy males and females (n = 8 each) completed two trials, performing morning exercise at 10:30 (AMEx) or evening exercise at 18:30 (PMEx). Exercise consisted of 30 min steady-state cycling (60% V˙ O

Purpose We previously observed increased energy intake (EI) at the meal before planned afternoon exercise, but the proximity of the meal to exercise might have reduced the scale of the pre-exercise anticipatory eating. Therefore, this study examined EI in the 24 h before fasted morning exercise. Methods Fourteen males, experienced with gym-based aerobic exercise (age 25 ± 5 years, BMI 23.8 ± 2.5 kg/m2), completed counterbalanced exercise (EX) and resting (REST) trials. On day 1, subjects were told the following morning’s activity (EX/REST), before eating ad-libitum laboratory-based breakfast and lunch meals and a home-based afternoon/evening food pack. The following morning, subjects completed 30-min cycling and 30-min running (EX; 3274 ± 278 kJ) or 60-min supine rest (REST; 311 ± 34 kJ) fasted. Appetite was measured periodically, and EI quantified. Results Afternoon/evening EI (EX 7371 ± 2176 kJ; REST 6437 ± 2070 kJ; P = 0.017) and total 24-h EI (EX 14,055 ± 3672 kJ; REST 12,718 ± 3379 kJ; P = 0.011) were greater during EX, with no difference between trials at breakfast (P = 0.761) or lunch (P = 0.071). Relative EI (EI minus energy expended through EX/REST) was lower in EX (EX 10,781 ± 3539 kJ; REST 12,407 ± 3385 kJ; P = 0.004). Conclusion This study suggests planned fasted aerobic exercise increases EI during the preceding afternoon/evening, precipitating a ~ 10% increase in EI in the preceding 24-h. However, this increase did not fully compensate for energy expended during exercise; meaning exercise induced an acute negative energy balance.

This study tested the hypothesis that exposure to chlorine-sterilised pool water would impair oral nitrate reduction (ONR). ONR was assessed in elite swimmers before and after morning and afternoon pool-based training. Nonswimmers were only assessed in the morning. ONR was similar in swimmers and nonswimmers (P = 1.000) and unchanged before and after morning and afternoon training (P ≥ 0.341). Therefore, exposure to chlorinated pool water does not interfere with ONR. Novelty Exposure to chlorine-sterilised pool water does not impair oral nitrate reduction in elite swimmers.

La guia CONSORT (CONsolidated Standards Of Reporting Trials)de 2010 (http://www.consort-statement.org/consort-2010) fuedesarrollada para mejorar el informe de ensayos clinicoscontrolados aleatorios de grupos paralelos, por lo que elcumplimiento de los estandares establecidos se puede demostrarmediante la cumplimentacion de la lista de chequeo CONSORT20101. Las principales revistas medicas han respaldado estainiciativa, que sin duda ha mejorado la realizacion y el informe deresultados de la investigacion clinica y sanitaria. La investigacionen el campo de la nutricion deportiva y el metabolismo delejercicio se beneficiara de estandares similares, pero comunmenteutiliza disenos de investigacion diferentes a los ensayos clinicos degrupos paralelos, como los experimentos cruzados.Se ha publicado recientemente una ampliacion de CONSORT queaborda ensayos cruzados aleatorios2, con una lista de verificacionrevisada que se centra en cuestiones de primera relevancia paraensayos clinicos que abordan tratamientos medicos o deasistencia medica. Sin embargo, estas cuestiones especificas de losensayos clinicos, pueden tener una relevancia diferente, cuando seconsideran en relacion con los experimentos mecanicistas,estrictamente controlados, realizados en laboratorio, que sonhabituales en la ciencia del ejercicio. Por ejemplo, los disenoscruzados pueden implicar efectos de orden entre evaluaciones; enlos ensayos clinicos, esto suele ocurrir con mayor frecuenciadebido al tratamiento o la intervencion en si, lo que requiere unintervalo de lavado suficiente, antes de repetir las evaluaciones.Por el contrario, la tendencia en la investigacion sobre nutriciondeportiva, se relaciona comunmente con la evaluacion en simisma, que a menudo, tiende a ser mas invasiva o exigente para elparticipante, que una instantanea sobre su estado de salud. Dehecho, las pruebas fisicas de rendimiento humano sonparticularmente propensas a efectos de aprendizaje o fatiga eincluso algunas adaptaciones fisicas pueden persistir durantesemanas o meses despues del primer test. Por ejemplo, eldenominado “efecto de intentos repetidos”, que describe como unasola exposicion a un ejercicio fisico desacostumbrado que producedano muscular puede inducir una profunda y duradera proteccionante ejercicios similares en el futuro3,4. Los participantes enensayos de ejercicio tambien pueden ser atletas de elite, cuyosniveles habituales de actividad fisica (y dieta) pueden mostrarvariaciones profundas a lo largo del tiempo (es decir,periodizacion), lo que complica aun mas la interpretacion deestudios longitudinales.La lista de chequeo PRESENT (Proper Reporting of Evidence inSport & Exercise Nutrition Trials) 2020 (Ver Anexo), por tanto, seha adaptado de la guia CONSORT para abordar especificamente lacombinacion unica de desafios y oportunidades que enfrentan losinvestigadores dentro de los amplios campos de la nutriciondeportiva y el metabolismo del ejercicio. El presente documentocomplementa y desarrolla la lista de verificacion CONSORT alponer enfasis y proveer ejemplos comunes o de mayor relevanciapara la investigacion en esta area tematica. La lista decomprobacion PRESENT 2020 se diseno teniendo en cuenta lanecesidad de minimizar a los autores la sobrecarga que suponeasegurarse de que el informe de sus resultados cumpla con losrequisitos de calidad; deberia permitir a los investigadoresdeterminar rapidamente si toda la informacion relevante estaincluida en su manuscrito. Por supuesto, es posible cumplir contodos los factores en la lista de verificacion a pesar de haberrealizado un mal estudio y/o haber informado mal de un buenestudio, mientras que algunos elementos de la lista de chequeopueden no ser aplicables incluso para investigacionesrigurosamente realizadas. No obstante, la consideracion ydiscusion de los factores identificados en la lista de chequeodeberia mejorar la comunicacion de los resultados de lainvestigacion relacionada con el ejercicio y la nutricion, en elfuturo inmediato, y tiene el potencial de mejorar el diseno y larealizacion de ensayos a largo plazo.

Eight well-trained cyclists ingested 68 g·h−1 of a carbohydrate-electrolyte solution with sodium alginate and pectin (CHO-ALG) or a taste and carbohydrate type-matched carbohydrate-electrolyte solution (CHO) during 120 min of cycling at 55% maximal power followed by an ∼20 min time trial. Oxygen uptake, carbon dioxide production, blood glucose concentration, substrate oxidation, gastrointestinal symptoms, and time trial performance (CHO-ALG: 1219 ± 84 s, CHO: 1267 ± 102 s; P = 0.185) were not different between trials. Novelty Inclusion of sodium alginate and pectin in a carbohydrate drink does not influence blood glucose, substrate oxidation, gastrointestinal comfort, or performance in cyclists.

Background: The role of nutrient timing in energy intake amongst people with dysglycaemia is understudied but could be a simple method to help regulate appetite. This study analysed within-person associations of sugar intake at breakfast and subsequent energy intake. Methods: We used 4-day diet diary data from 147 participants (47 % men) encompassing 547 days of diet recording in the Sedentary Time and Metabolic Health in People with Type 2 diabetes project (STAMP-2). Linear two-level models were used to investigate within- (day-level) and between-person (participant-level) variation in total and post-breakfast energy intake according to skipping breakfast, low- (> 0-14.2 g) or high- (> 14.2 g) sugar intake at breakfast, adjusting for potential confounding or mediation. Results: Post-breakfast energy intakes were observed to be lower after eating low- and high-sugar breakfasts (compared to skipping), but higher total energy intake was associated with eating a high-sugar breakfast. Compared to breakfast skipping, both low- and high-sugar breakfasts were strongly associated with lower post-breakfast energy intake (-178, 95 % confidence interval [CI] -261, -94 kcal/d; ‑151, 95 % CI -235, -67 kcal/d, respectively). However, compared to skipping breakfast, low-sugar breakfasts were weakly associated with higher total daily energy intake (64, 95 % CI -18, 146 kcal/d), whereas high-sugar breakfasts had a strong association (135, 95 % CI 52, 217 kcal/d). Post-breakfast energy intakes were similar between low- and high-sugar breakfast days (27, 95 % CI -53, 106 kcal/d), whilst total daily energy intake tended to be higher with high- (compared to low-) sugar breakfasts (70, -8, 149 kcal/d). We also observed evidence of energy compensation whereby 86 % of the extra energy consumed in a low-sugar breakfast was compensated for by reductions in post-breakfast energy intakes, compared to only 53 % after a high-sugar breakfast. Conclusion: Overall, high-, but not low-, sugar breakfasts were associated with higher total daily energy intake when compared to breakfast skipping, despite a similar reduction in post-breakfast energy intake. We found evidence of poorer post-breakfast energy intake compensation with high-sugar breakfasts than low-sugar breakfasts. These findings suggest portion size may be important to consider in future breakfast research, with sugar being a proxy of portion size.

Aims: To examine the independent associations between relative protein intake (g kg−1 day 1) and markers of physical function in those with type 2 diabetes, while also comparing with current guidelines for protein intake. Methods: This analysis reports data from the ongoing Chronotype of Patients with Type 2 Diabetes and Effect on Glycaemic Control (CODEC) study. Functional assessments included: Short Physical Performance Battery (SPPB), 60 s sit-to-stand (STS-60), 4-m gait speed, time to rise from a chair (×5) and handgrip strength. Participants also completed a self-reported 4 day diet diary. Regression analyses assessed whether relative protein intake was associated with markers of physical function. Interaction terms assessed whether the associations were modified by sex, age, HbA1c or body mass index (BMI). Results413 participants were included (mean ± SD:age = 65.0 ± 7.7 years, 33% female, BMI = 30.6 ± 5.1 kg/m2). The average total protein intake was 0.88 ± 0.31 g kg⁻¹ day⁻¹ . 33% of individuals failed to meet the reference nutrient intake for the United Kingdom (≥0.75 g kg⁻¹ day⁻¹ ), and 87% for European recommendations (≥1.2 g kg⁻¹ day⁻¹ ). After adjustment, each 0.5 g/kg of protein intake was associated with an 18.9% (95% CI: 2.3, 35.5) higher SPPB score, 22.7% (1.1, 44.3) more repetitions in STS-60, 21.1% (4.5, 37.7) faster gait speed and 33.2% (16.9, 49.5) lower chair rise time. There were no associations with handgrip strength or any interactions. Conclusions: Relative protein intake was positively associated with physical function outcomes, even after consideration of total energy intake. As a number of individuals were below the current guidelines, protein intake may be a modifiable factor of importance for people with type 2 diabetes. Refereed/Peer-reviewed

Purpose This study aimed to assess the effects of consuming a very-low-energy placebo breakfast on subsequent appetite and lunch energy intake. Methods Fourteen healthy males consumed water-only (WAT), very-low-energy, viscous placebo (containing water, low-calorie flavoured squash, and xanthan gum; ~ 16 kcal; PLA), and whole-food (~ 573 kcal; FOOD) breakfasts in a randomised order. Subjects were blinded to the energy content of PLA and specific study aims. Venous blood samples were collected pre-breakfast, 60- and 180-min post-breakfast to assess plasma acylated ghrelin and peptide tyrosine tyrosine concentrations. Subjective appetite was measured regularly, and energy intake was assessed at an ad libitum lunch meal 195-min post-breakfast. Results Lunch energy intake was lower during FOOD compared to WAT (P P ≥ 0.132). Cumulative energy intake (breakfast plus lunch) was lower during PLA (1078 ± 274 kcal) and WAT (1093 ± 249 kcal), compared to FOOD (1554 ± 301 kcal; P P P P P ≥ 0.071). Conclusion Consuming a very-low-energy placebo breakfast does not alter energy intake at lunch but may reduce cumulative energy intake across breakfast and lunch and attenuate elevations in subjective appetite associated with breakfast omission. Trial registration NCT04735783, 2nd February 2021, retrospectively registered.

The impact of alterations in hydration status on human physiology and performance responses during exercise is one of the oldest research topics in sport and exercise nutrition. This body of work has mainly focussed on the impact of reduced body water stores (i.e. hypohydration) on these outcomes, on the whole demonstrating that hypohydration impairs endurance performance, likely via detrimental effects on a number of physiological functions. However, an important consideration, that has received little attention, is the methods that have traditionally been used to investigate how hypohydration affects exercise outcomes, as those used may confound the results of many studies. There are two main methodological limitations in much of the published literature that perhaps make the results of studies investigating performance outcomes difficult to interpret. First, subjects involved in studies are generally not blinded to the intervention taking place (i.e. they know what their hydration status is), which may introduce expectancy effects. Second, most of the methods used to induce hypohydration are both uncomfortable and unfamiliar to the subjects, meaning that alterations in performance may be caused by this discomfort, rather than hypohydration per se. This review discusses these methodological considerations and provides an overview of the small body of recent work that has attempted to correct some of these methodological issues. On balance, these recent blinded hydration studies suggest hypohydration equivalent to 2–3% body mass decreases endurance cycling performance in the heat, at least when no/little fluid is ingested.

Effects of exercise on subsequent energy intake are well documented, but whether preexercise energy intake is affected by future planned exercise is unknown. This study investigated the effect of planned late-afternoon exercise on appetite and energy intake before (breakfast and lunch) and after (evening meal/snacks) exercise.Twenty healthy, active participants (10 male; age, 23 ± 5 yr; body mass index 23.7 ± 3.2 kg·m; V˙O2peak, 44.1 ± 5.4 mL·kg··min) completed randomized, counterbalanced exercise (EX) and resting (REST) trials. After trial notification, participants were provided ad libitum breakfast (0800 h) and lunch (1200 h) in the laboratory, before completing 1-h exercise (30-min cycling, 30-min running) at 75%-80% maximal HR (EX, 2661 ± 783 kJ) or 1-h supine rest (REST, 310 ± 58 kJ) 3 h after lunch. Participants were provided a food pack (pasta meal/snacks) for consumption after exercise (outside laboratory). Appetite was measured regularly, and meal and 24-h energy intake were quantified.Ad libitum energy intake was greater during EX at lunch (EX, 3450 ± 1049 kJ; REST, 3103 ± 927 kJ; P = 0.004), but similar between trials at breakfast (EX, 2656 ± 1291 kJ; REST, 2484 ± 1156 kJ; P = 0.648) and dinner (EX, 6249 ± 2216 kJ; REST, 6240 ± 2585 kJ; P = 0.784). Total 24-h energy intake was similar between trials (P = 0.388), meaning that relative energy intake (24-h energy intake minus EX/REST energy expenditure) was reduced during EX (EX, 9694 ± 3313 kJ; REST, 11,517 ± 4023 kJ; P = 0.004).Energy intake seems to be increased in anticipation of, rather than in response to, aerobic exercise, but the increase was insufficient to compensate for energy expended during exercise, meaning that aerobic exercise reduced energy balance relative to rest.

The practice of rapid weight loss (RWL) in mixed martial arts (MMA) is an increasing concern but data remain scarce. The aim of this study was to investigate the prevalence, magnitude, methods, and influencers of RWL in professional and amateur MMA athletes. MMA athletes (N = 314; 287 men and 27 women) across nine weight categories (strawweight to heavyweight), completed a validated questionnaire adapted for this sport. Sex-specific data were analyzed, and subgroup comparisons were made between athletes competing at professional and amateur levels. Most athletes purposefully reduced body weight for competition (men: 97.2%; women: 100%). The magnitude of RWL in 1 week prior to weigh-in was significantly greater for professional athletes compared with those competing at amateur level (men: 5.9% vs. 4.2%; women: 5.0% vs. 2.1% of body weight; p p always” or “sometimes” used water loading (72.9%), restricting fluid intake (71.3%), and sweat suits (55.4%) for RWL. Coaches were cited as the primary source of influence on RWL practices (men: 29.3%; women: 48.1%). There is a high reported prevalence of RWL in MMA, at professional and amateur levels. Our findings, constituting the largest inquiry to date, call for urgent action from MMA organizations to safeguard the health and well-being of athletes competing in this sport.

In many situations, meals are planned (i.e. what and how much) before they are eaten, but how exercise influences this planning is unknown. Therefore, this study investigated whether anticipation of an exercise session alters food intake planned for post-exercise. Forty (16 male) regular exercisers (mean ± SD; age 23.3 ± 5.6 y, BMI 22.7 ± 3.3 kg/m2, body fat 25.6 ± 7.6%) completed the study. Subjects arrived ≥3 h post-prandial and were given two hypothetical scenarios for the following day: 1) morning rest (REST), or 2) morning rest with the addition of 1 h of hard aerobic exercise at 10:00–11:00 (EXERCISE). For each scenario subjects had to plan their lunch, to consume at 12:00, by serving themselves cheesy tomato pasta and chocolate buttons. Scenarios were randomised and separated by 5 min and foods were not consumed. EXERCISE increased total energy served by 24% (EXERCISE 3308 ± 1217 kJ; REST 2663 ± 924 kJ; P

Bin Naharudin, MN, Yusof, A, Shaw, H, Stockton, M, Clayton, DJ, and James, LJ. Breakfast omission reduces subsequent resistance exercise performance. J Strength Cond Res 33(7): 1766-1772, 2019-Although much research has examined the influence of morning carbohydrate intake (i.e., breakfast) on endurance performance, little is known about its effects on performance in resistance-type exercise. Sixteen resistance-trained men (age 23 ± 4 years, body mass 77.56 ± 7.13 kg, and height 1.75 ± 0.04 m) who regularly (≥3 day/wk) consumed breakfast completed this study. After assessment of 10 repetition maximum (10RM) and familiarization process, subjects completed 2 randomized trials. After an overnight fast, subjects consumed either a typical breakfast meal (containing 1.5 g of carbohydrate/kg; breakfast consumption [BC]) or a water-only breakfast (breakfast omission [BO]). Two hours later, subjects performed 4 sets to failure of back squat and bench press at 90% of their 10RM. Sensations of hunger, fullness, desire to eat, and prospective food consumption were collected before, as well as immediately, 1 hour and 2 hours after BC/BO using 100-mm visual analogue scales. Total repetitions completed were lower during BO for both back squat (BO: 58 ± 11 repetitions; BC: 68 ± 14 repetitions; effect size [ES] = 0.98; p < 0.001) and bench press (BO: 38 ± 5 repetitions; BC: 40 ± 5 repetitions; ES = 1.06; p < 0.001). Fullness was greater, whereas hunger, desire to eat, and prospective food consumption were lower after a meal for BC compared with BO (p < 0.001). The results of this study demonstrate that omission of a pre-exercise breakfast might impair resistance exercise performance in habitual breakfast consumers. Therefore, consumption of a high-carbohydrate meal before resistance exercise might be a prudent strategy to help maximize performance.

Objectives Ingested ketogenic agents offer the potential to enhance endurance performance via the provision of an alternative exogenous, metabolically efficient, glycogen-sparing fuel (i.e. ketone bodies). This study aimed to assess the impact of combined carbohydrate and 1,3-butanediol (CHO-BD) supplementation on endurance performance, blood beta-hydroxybutyrate (βHB) concentration and glycolytic activity, in comparison to carbohydrate supplementation alone (CHO). Design Eleven male runners (age 38 ± 12 years, mass 67.3 ± 6.5 kg, height 174.5 ± 5.0 cm, V ˙ O 2 p e a k 64.2 ± 5.0 ml⋅kg−1⋅min−1) performed two experimental trials in a randomised crossover design. Methods Each trial consisted of 60 min of submaximal running, followed by a 5 km running time-trial (TT), and was performed following the ingestion of an energy matched ∼650 ml drink (CHO-BD or CHO). Results There was no difference in TT completion time between the trials (CHO: 1265 ± 93, CHO-BD: 1261 ± 96 s; p = 0.723). However, blood βHB concentration in the CHO-BD trial was at least double that of the CHO trial at all time points following supplementation (p Conclusions An energy matched CHO-BD supplementation drink raised βHB concentration and acutely lowered blood lactate concentration, without enhancing 5 km TT running performance.

This study demonstrates a scenario of industrial reformulation by developing muffins that resemble store-branded ones and testing the possibility of reformulating them using inulin and green banana flour (GBF). Ten different formulations were created through reducing 10% or 30% of sugar and/or fat. Physical characteristics, consumer acceptance and purchase preferences, baking losses, nutritional properties, shelf-life, as well as cost and industrial processability were considered and discussed. Results on physical properties showed that firmness had increased in reformulated muffins while springiness only decreased when both sugar and fat were reduced by 30% (p &lt, 0.05). Texture and sensory properties of reformulated muffins were acceptable, and the purchase intent rate was high. Regarding the nutritional properties, muffins incorporating more than 10% of fibres allowed the addition of nutritional claims. The incremental area under the curve iAUC120min of blood glucose in healthy adults (n = 13) was significantly lower than control after ingesting 30% reduced sugar or fat muffins using inulin (p &lt, 0.01). The microbial profile was not affected by reformulation during storage at 25 °C for 10 days. This study concluded that there is a significant potential to industrially produce reduced sugar or fat muffins using inulin or GBF up to 30% without significantly deteriorating quality attributes.

This study aimed to assess the effects of consuming a very-low-energy placebo breakfast on subsequent appetite and lunch energy intake.Fourteen healthy males consumed water-only (WAT), very-low-energy, viscous placebo (containing water, low-calorie flavoured squash, and xanthan gum; ~ 16 kcal; PLA), and whole-food (~ 573 kcal; FOOD) breakfasts in a randomised order. Subjects were blinded to the energy content of PLA and specific study aims. Venous blood samples were collected pre-breakfast, 60- and 180-min post-breakfast to assess plasma acylated ghrelin and peptide tyrosine tyrosine concentrations. Subjective appetite was measured regularly, and energy intake was assessed at an ad libitum lunch meal 195-min post-breakfast.Lunch energy intake was lower during FOOD compared to WAT (P 0.05), with no further differences between trials (P ≥ 0.132). Cumulative energy intake (breakfast plus lunch) was lower during PLA (1078 ± 274 kcal) and WAT (1093 ± 249 kcal), compared to FOOD (1554 ± 301 kcal; P 0.001). Total area under the curve (AUC) for hunger, desire to eat and prospective food consumption were lower, and fullness was greater during PLA and FOOD compared to WAT (P 0.05). AUC for hunger was lower during FOOD compared to PLA (P 0.05). During FOOD, acylated ghrelin was suppressed compared to PLA and WAT at 60 min (P 0.05), with no other hormonal differences between trials (P ≥ 0.071).Consuming a very-low-energy placebo breakfast does not alter energy intake at lunch but may reduce cumulative energy intake across breakfast and lunch and attenuate elevations in subjective appetite associated with breakfast omission.NCT04735783, 2nd February 2021, retrospectively registered.

Cow’s milk is a naturally nutrient-dense foodstuff. A significant source of many essential nutrients, its inclusion as a component of a healthy balanced diet has been long recommended. Beyond milk’s nutritional value, an increasing body of evidence illustrates cow’s milk may confer numerous benefits related to health. Evidence from adult populations suggests that cow’s milk may have a role in overall dietary quality, appetite control, hydration and cognitive function. Although evidence is limited compared with the adult literature, these benefits may be echoed in recent paediatric studies. This article, therefore, reviews the scientific literature to provide an evidence-based evaluation of the associated health benefits of cow’s milk consumption in primary-school-aged children (4–11 years). We focus on seven key areas related to nutrition and health comprising nutritional status, hydration, dental and bone health, physical stature, cognitive function, and appetite control. The evidence consistently demonstrates cow’s milk (plain and flavoured) improves nutritional status in primary-school-aged children. With some confidence, cow’s milk also appears beneficial for hydration, dental and bone health and beneficial to neutral concerning physical stature and appetite. Due to conflicting studies, reaching a conclusion has proven difficult concerning cow’s milk and cognitive function; therefore, a level of caution should be exercised when interpreting these results. All areas, however, would benefit from further robust investigation, especially in free-living school settings, to verify conclusions. Nonetheless, when the nutritional-, physical- and health-related impact of cow’s milk avoidance is considered, the evidence highlights the importance of increasing cow’s milk consumption.

This study examined sweat rate, sweat sodium concentration [Na+], and ad-libitum carbohydrate and fluid intakes in elite female soccer players during training (n = 19) and a match (n = 8); eight completed both for comparisons. Body mass (kg) was obtained before and after exercise to calculate sweat rate. The sweat [Na+] was determined from absorbent patches on the thigh or back. Sweat rate, percentage body mass change, and sweat [Na+] for 19 players during training were 0.47 ± 0.19 L·h−1, +0.19 ± 0.65%, and 28 ± 10 mmol·L−1, respectively. Sweat rate was higher during a match (0.98 ± 0.34 L·h−1) versus training (0.49 ± 0.26 L·h−1, p = 0.007). Body mass losses were greater post-match (−1.12 ± 0.86%) than training (+0.29 ± 0.34%, p = 0.003). Sweat [Na+] was similar for training (29 ± 9 mmol·L−1) and a match (35 ± 9 mmol·L−1) (p = 0.215). There were no differences in match versus training carbohydrate intakes (2.0 ± 2.3 g·h−1, 0.9 ± 1.5 g·h−1, respectively, p = 0.219) or fluid intakes (0.71 ± 0.30 L·h−1, 0.53 ± 0.21 L·h−1, respectively, p = 0.114). In conclusion, female soccer players’ sweat rates were higher during a match than during training, and carbohydrate intakes were below recommendations for matches and training.

Background: Preexercise food intake enhances exercise performance due, in part, to the provision of exogenous carbohydrate. Food intake also suppresses hunger, but the specific influence of hunger on exercise performance has not been investigated. This study aimed to manipulate hunger by altering preexercise meal viscosity to examine whether hunger influences performance. Methods: Sixteen resistance-trained males completed 2 experimental trials ingesting either high viscosity semisolid (SEM) and low viscosity liquid (LIQ) carbohydrate-containing meals 2 hours before performing 4 sets of back squat (85 [22] kg) and bench press (68 [13] kg) to failure at 90% 10-repetition maximum. Subjective hunger/fullness as well as plasma concentrations of glucose, insulin, ghrelin, and peptide tyrosine–tyrosine were measured before and periodically after the meal. Repetitions completed in sets were used to determine exercise performance. Results: Hunger was lower, and fullness was greater during SEM compared with LIQ immediately before and during exercise (P P = .001) with no difference in bench press repetitions (SEM 48 [11]; LIQ 48 [10] repetitions; P = .621). Postprandial glucose concentrations were greater during LIQ (12% increase in peak glucose) but were similar throughout exercise. Conclusion: This study demonstrates that exercise performance in back squat was increased in the SEM trial concomitant to a reduction in hunger. Therefore, this study provides novel data that suggest that exercise performance might be influenced by hunger, at least for resistance exercise.

Purpose Whilst there is evidence to suggest that hypohydration caused by physical work in the heat increases renal injury, whether this is the case during exercise in temperate conditions remains unknown. This study investigated the effect of manipulating hydration status during high-intensity intermittent running on biomarkers of renal injury. Methods After familiarisation, 14 males (age: 33 ± 7 years; V̇O2peak: 57.1 ± 8.6 ml/kg/min; mean ± SD) completed 2 trials in a randomised cross-over design, each involving 6, 15 min blocks of shuttle running (modified Loughborough Intermittent Shuttle Test protocol) in temperate conditions (22.3 ± 1.0 °C; 47.9 ± 12.9% relative humidity). During exercise, subjects consumed either a volume of water equal to 90% of sweat losses (EU) or 75 mL water (HYP). Body mass, blood and urine samples were taken pre-exercise (baseline/pre), 30 min post-exercise (post) and 24 h post-baseline (24 h). Results Post-exercise, body mass loss, serum osmolality and urine osmolality were greater in HYP than EU (P ≤ 0.024). Osmolality-corrected urinary kidney injury molecule-1 (uKIM-1) concentrations were increased post-exercise (P ≤ 0.048), with greater concentrations in HYP than EU (HYP: 2.76 [1.72–4.65] ng/mOsm; EU: 1.94 [1.1–2.54] ng/mOsm; P = 0.003; median [interquartile range]). Osmolality-corrected urinary neutrophil gelatinase-associated lipocalin (uNGAL) concentrations were increased post-exercise (P P = 0.073). Conclusion These results suggest that hypohydration produced by high-intensity intermittent running increases renal injury, compared to when euhydration is maintained, and that the site of this increased renal injury is at the proximal tubules.

Hypohydration increases physiological strain and reduces physical and technical soccer performance, but there are limited data on how fluid balance responses change between different types of sessions in professional players. This study investigated sweat and fluid/carbohydrate intake responses in elite male professional soccer players training at low and high intensities in cool and hot environments. Fluid/sodium (Na+) losses and ad-libitum carbohydrate/fluid intake of fourteen elite male soccer players were measured on four occasions: cool (wet bulb globe temperature (WBGT): 15 &plusmn, 7 &deg, C, 66 &plusmn, 6% relative humidity (RH)) low intensity (rating of perceived exertion (RPE) 2&ndash, 4, m&middot, min&minus, 1 40&ndash, 46) (CL), cool high intensity (RPE 6&ndash, 8, m&middot, 1 82&ndash, 86) (CH), hot (29 &plusmn, 1 &deg, C, 52 &plusmn, 7% RH) low intensity (HL), hot high intensity (HH). Exercise involved 65 &plusmn, 5 min of soccer-specific training. Before and after exercise, players were weighed in minimal clothing. During training, players had ad libitum access to carbohydrate beverages and water. Sweat [Na+] (mmol&middot, L&minus, 1), which was measured by absorbent patches positioned on the thigh, was no different between conditions, CL: 35 &plusmn, 9, CH: 38 &plusmn, 8, HL: 34 &plusmn, 70.17, HH: 38 &plusmn, 8 (p = 0.475). Exercise intensity and environmental condition significantly influenced sweat rates (L&middot, h&minus, 1), CL: 0.55 &plusmn, 0.20, CH: 0.98 &plusmn, 0.21, HL: 0.81 &plusmn, 0.17, HH: 1.43 &plusmn, 0.23 (p =0.001), and percentage dehydration (p &lt, 0.001). Fluid intake was significantly associated with sweat rate (p = 0.019), with no players experiencing hypohydration &gt, 2% of pre-exercise body mass. Carbohydrate intake varied between players (range 0&ndash, 38 g&middot, 1), with no difference between conditions. These descriptive data gathered on elite professional players highlight the variation in the hydration status, sweat rate, sweat Na+ losses, and carbohydrate intake in response to training in cool and hot environments and at low and high exercise intensities.

This study investigated metabolic, endocrine, appetite and mood responses to a maximal eating occasion in fourteen men (mean: age 28 (sd5) years, body mass 77·2 (sd6·6) kg and BMI 24·2 (sd2·2) kg/m2) who completed two trials in a randomised crossover design. On each occasion, participants ate a homogenous mixed-macronutrient meal (pizza). On one occasion, they ate until ‘comfortably full’ (ad libitum) and on the other, until they ‘could not eat another bite’ (maximal). Mean energy intake was double in the maximal (13 024 (95 % CI 10 964, 15 084) kJ; 3113 (95 % CI 2620, 3605) kcal) compared with thead libitumtrial (6627 (95 % CI 5708, 7547) kJ; 1584 (95 % CI 1364, 1804) kcal). Serum insulin incremental AUC (iAUC) increased approximately 1·5-fold in the maximal compared withad libitumtrial (mean:ad libitum43·8 (95 % CI 28·3, 59·3) nmol/l × 240 min and maximal 67·7 (95 % CI 47·0, 88·5) nmol/l × 240 min,P< 0·01), but glucose iAUC did not differ between trials (ad libitum94·3 (95 % CI 30·3, 158·2) mmol/l × 240 min and maximal 126·5 (95 % CI 76·9, 176·0) mmol/l × 240 min,P= 0·19). TAG iAUC was approximately 1·5-fold greater in the maximalv.ad libitumtrial (ad libitum98·6 (95 % CI 69·9, 127·2) mmol/l × 240 min and maximal 146·4 (95 % CI 88·6, 204·1) mmol/l × 240 min,P< 0·01). Total glucagon-like peptide-1, glucose-dependent insulinotropic peptide and peptide tyrosine–tyrosine iAUC were greater in the maximal compared withad libitumtrial (P< 0·05). Total ghrelin concentrations decreased to a similar extent, but AUC was slightly lower in the maximalv.ad libitumtrial (P= 0·02). There were marked differences on appetite and mood between trials, most notably maximal eating caused a prolonged increase in lethargy. Healthy men have the capacity to eat twice the energy content required to achieve comfortable fullness at a single meal. Postprandial glycaemia is well regulated following initial overeating, with elevated postprandial insulinaemia probably contributing.

Exercise intensity affects many potential postprandial responses, but there is limited information on the influence of exercise modality. Therefore, the aim of this study was to investigate if the nature of exercise at two different intensities would affect gastric emptying rate (GER), appetite and metabolic responses following ingestion of a semi-solid meal. Twelve healthy men completed, in a random order, four 60-min cycles at 60% VO2peak (MOD), 40% VO2peak (LOW) and in a continuous (CON) or intermittent (INT) manner. INT consisted of 20 &times, 1-min exercise bouts with 2-min rest breaks. INT and CON were matched for total work output at each intensity. GER of the post-exercise meal was measured for 2 h using the 13C-breath method. Blood glucose, substrate utilisation and appetite ratings were measured at regular intervals throughout all trials and 24-h energy intake (EI) post-trials was assessed. GER-Delta over Baseline (DOB) was lower (p &lt, 0.05) on MOD-INT vs. MOD-CON from 30&ndash, 120 min post-meal. Blood glucose was higher mid-exercise (p &lt, 0.05) on MOD-INT vs. MOD-CON. Although post-exercise LOW-CON was significantly higher than LOW-INT (p &lt, 0.05), blood glucose was also higher 30-min post-meal ingestion on both CON trials compared to INT (p &lt, 0.001). No interaction effect was observed for perceived appetite responses 2 h after meal ingestion (all p &gt, 0.05). 24-h post-trial EI was similar between LOW-CON vs. LOW-INT (p &gt, 0.05), although MOD-INT vs. MOD-CON 3500 &plusmn, 1419 vs. 2556 &plusmn, 989 kCal: p &lt, 0.001 was elevated. In summary, MOD-INT exercise delays GER without stimulating perceived appetite in the 2 h period after meal ingestion, although EI was greater in the 24-h post-trial.

This study investigated whether supplementation with nitrate-rich beetroot juice (BR) can improve high-intensity intermittent running performance in trained males in normoxia and different doses of normobaric hypoxia. Eight endurance-trained males (, 62 ± 6 ml·kg−1·min−1) completed repeated 90 s intervals at 110% of peak treadmill velocity, from an initial step incremental test, interspersed by 60 s of passive recovery until exhaustion (Tlim). Participants completed the first three experimental trials during days 3, 5, and 7 of BR or nitrate-depleted beetroot juice (PLA) supplementation and completed the remaining experimental visits on the alternative supplement following at least 7 days of washout. The fraction of inspired oxygen during visits 1–3 was either 0.209, 0.182, or 0.157, equivalent to an altitude of 0, 1,200, and 2,400 m, respectively, and this order was replicated on visits 4–6. Arterial oxygen saturation declined dose dependently as fraction of inspired oxygen was lowered (p p lim between PLA and BR at 0 m (445 [324, 508] and 410 [368, 548] s); 1,200 m (341 [270, 390] and 332 [314, 356] s); or 2,400 m (233 [177, 373] and 251 [221, 323] s) (median and [interquartile range]; p > .05). The findings from this study suggest that short-term BR supplementation does not improve high-intensity intermittent running performance in endurance-trained males in normoxia or at doses of normobaric hypoxia that correspond to altitudes at which athletes typically train while on altitude training camps.

Objective This study investigated the effect of 3 weeks of high‐sugar (“Sweet”) versus low‐sugar (“Plain”) breakfast on energy balance, metabolic health, and appetite. Methods A total of 29 healthy adults (22 women) completed this randomized crossover study. Participants had pre‐ and postintervention appetite, health, and body mass outcomes measured, and they recorded diet, appetite (visual analogue scales), and physical activity for 8 days during each intervention. Interventions were 3 weeks of isoenergetic Sweet (30% by weight added sugar; average 32 g of sugar) versus Plain (no added sugar; average 8 g of sugar) porridge‐based breakfasts. Results Pre‐ to postintervention changes in body mass were similar between Plain (Δ 0.1 kg; 95% CI: −0.3 to 0.5 kg) and Sweet (Δ 0.2 kg; 95% CI: −0.2 to 0.5 kg), as were pre‐ to postintervention changes for biomarkers of health (all P ≥ 0.101) and psychological appetite (all P ≥ 0.152). Energy, fat, and protein intake was not statistically different between conditions. Total carbohydrate intake was higher during Sweet (287 ± 82 g/d vs. 256 ± 73 g/d; P = 0.009), driven more by higher sugar intake at breakfast (116 ± 46 g/d vs. 88 ± 38 g/d; P

Objectives: Short periods of excessive consumption of indulgent high-fat foods are common in Western society, but the effect this has on bone is unknown. The aim of this pilot study was to explore how a 7-d hyperenergetic, high-fat diet affects candidate biomarkers of bone metabolism.\ud \ud Methods: The study included 12 healthy men with a mean age of 24 y (SD = 4 y) and body mass index (BMI) of 24.1 kg/m2 (SD = 1.5). The men consumed a 7-d hyperenergetic, high-fat diet (HE-HFD; 20.9 [SD = 0.8] MJ; 65% total energy as fat) and a control (CON) diet (10.9 [SD = 2] MJ; 36% total energy as fat), in randomized, crossover order, with each trial separated by 3 wk. Markers of bone formation (P1NP) and bone resorption (CTx) were measured at baseline and after 1, 3, and 7 d of each diet. Bone metabolic responses were analyzed using two-factor repeated-measures analysis of variance and subsequent pairwise comparisons.\ud \ud Results: There was a main effect of time (P < 0.05), but no trial (P = 0.270) or time- × -trial interaction (P = 0.693) effects for plasma concentrations of CTx. Mean CTx concentrations did not differ between trials (CON: 0.97 ng/mL [SD = 0.39]; HE-HFD: 1.03 ng/mL [SD = 0.22]; P = 0.225). There was a main effect of trial (P < 0.01), but no time (P = 0.138) or trial- × -interaction (P = 0.179) effects for plasma concentrations of P1NP. Mean P1NP concentrations were lower during the HE-HFD (61.79 ng/mL [SD = 26.54]) than during the CON diet (77.89 ng/mL [SD = 28.71]; P < 0.01).\ud \ud Conclusions: A 7-d hyperenergetic, high-fat diet reduces a marker of bone formation but does not affect a marker of bone resorption. This pilot study suggested that short periods of excessive energy and fat consumption may detrimentally affect bone health.

Post-exercise recovery is a multi-facetted process that will vary depending on the nature of the exercise, the time between exercise sessions and the goals of the exerciser. From a nutritional perspective, the main considerations are: (1) optimisation of muscle protein turnover; (2) glycogen resynthesis; (3) rehydration; (4) management of muscle soreness; (5) appropriate management of energy balance. Milk is approximately isotonic (osmolality of 280–290 mosmol/kg), and the mixture of high quality protein, carbohydrate, water and micronutrients (particularly sodium) make it uniquely suitable as a post-exercise recovery drink in many exercise scenarios. Research has shown that ingestion of milk post-exercise has the potential to beneficially impact both acute recovery and chronic training adaptation. Milk augments post-exercise muscle protein synthesis and rehydration, can contribute to post-exercise glycogen resynthesis, and attenuates post-exercise muscle soreness/function losses. For these aspects of recovery, milk is at least comparable and often out performs most commercially available recovery drinks, but is available at a fraction of the cost, making it a cheap and easy option to facilitate post-exercise recovery. Milk ingestion post-exercise has also been shown to attenuate subsequent energy intake and may lead to more favourable body composition changes with exercise training. This means that those exercising for weight management purposes might be able to beneficially influence post-exercise recovery, whilst maintaining the energy deficit created by exercise.

PURPOSE: To examine the effect on short duration, high intensity cycling time trial performance when a semi-solid breakfast containing carbohydrate or a taste and texture matched placebo is ingested 90 minutes pre-exercise compared to a water control. METHODS: Thirteen well trained cyclists (25 ± 8 years, 71.1 ± 5.9 kg, 1.76 ± 0.04 m, 383 ± 46 Wmax, VO2peak 4.42 ± 0.53 L·min-1) performed three experimental trials examining breakfast ingestion 90 minutes before a 10 minute steady state cycle (60% Wmax) and a ~20 minute time trial (to complete a workload target of 376 ± 36 kJ). Subjects consumed either water (WAT), a semi-solid carbohydrate breakfast (2 g carbohydrate·kg-1 body mass; CHO) or a taste and texture matched placebo (PLA). Blood lactate and glucose concentrations were measured periodically throughout the rest and exercise periods. RESULTS: The time trial was completed quicker in CHO (1120 ± 69 s; P=0.006) and PLA (1112 ± 50 s; P=0.030) compared to WAT (1146 ± 74 s). Ingestion of carbohydrate caused an increase in blood glucose concentration throughout the rest period in CHO (peak at 30 minutes rest: 7.37 ± 1.10 mmol·l-1; P

This systematic review examined the effects of whole protein and commonly consumed amino acid supplements on markers of exercise-induced inflammation and oxidative stress and was reported according to the PRISMA guidelines. MEDLINE and SPORTDiscus were searched from inception until June 2021. The inclusion criteria were randomized clinical trials in humans, healthy adult participants (≥18 years), dietary protein/amino acid interventions, and measurements of oxidative stress/the redox status or inflammation post-exercise. The Cochrane Collaboration risk of bias 2 tool was used to critically appraise the studies. Data extracted from thirty-four studies were included in the systematic review (totaling 757 participants with only 10 females; age range 19–40 years). The included trials examined five types of whole protein and seven different amino acids supplements; most studies (n = 20) failed to identify statistically significant effects on markers of inflammation or oxidative stress after exercise; some (n = 14) showed either anti-inflammatory or antioxidant effects on some, but not all, markers. In conclusion, we found weak and inconsistent evidence that dietary protein/amino acid interventions can modify exercise-induced changes in oxidative stress and inflammation. However, given that these were not the primary outcomes in many of the included studies and many had design limitations, further research is warranted (Open Science Framework registration number: 10.17605/OSF.IO/AGUR2).

Objectives This study investigated the influence of a moderate caffeine dose on endurance cycle performance and thermoregulation during prolonged exercise in high ambient temperature. Design Double-blind cross-over study. Methods Eight healthy, recreationally active males (mean ± SD; age: 22 ± 1 years; body mass: 71.1 ± 8.5 kg; VO2peak: 55.9 ± 5.8 mL kg−1 min−1; Wmax: 318 ± 37 W) completed one VO2peak test, one familiarisation trial and two experimental trials. After an overnight fast, participants ingested a placebo or a 6 mg kg−1 caffeine dose 60 min before exercise. The exercise protocol consisted of 60 min of cycle exercise at 55% Wmax, followed by a 30 min performance task (total kJ produced) in 30 °C and 50% RH. Results Performance was enhanced (Cohen’s d effect size = 0.22) in the caffeine trial (363.8 ± 47.6 kJ) compared with placebo (353.0 ± 49.0 kJ; p = 0.004). Caffeine did not influence core (p = 0.188) or skin temperature (p = 0.577) during exercise. Circulating prolactin (p = 0.572), cortisol (p = 0.842) and the estimated rates of fat (p = 0.722) and carbohydrate oxidation (p = 0.454) were also similar between trial conditions. Caffeine attenuated perceived exertion during the initial 60 min of exercise (p = 0.033), with no difference in thermal stress across trials (p = 0.911). Conclusions Supplementation with 6 mg kg−1 caffeine improved endurance cycle performance in a warm environment, without differentially influencing thermoregulation during prolonged exercise at a fixed work-rate versus placebo. Therefore, moderate caffeine doses which typically enhance performance in temperate environmental conditions also appear to benefit endurance performance in the heat.

The purpose of this study was to examine the efficacy of water and a 50 mmol/L NaCl solution on postexercise rehydration when a standard meal was consumed during rehydration. Eight healthy participants took part in two experimental trials during which they lost 1.5 ± 0.4% of initial body mass via intermittent exercise in the heat. Participants then rehydrated over a 60-min period with water or a 50 mmol/L NaCl solution in a volume equivalent to 150% of their body mass loss during exercise. In addition, a standard meal was ingested during this time which was equivalent to 30% of participants predicted daily energy expenditure. Urine samples were collected before and after exercise and for 3 hr after rehydration. Cumulative urine volume (981 ± 458 ml and 577 ± 345 mL; p = .035) was greater, while percentage fluid retained (50 ± 20% and 70 ± 21%; p = .017) was lower during the water compared with the NaCl trial respectively. A high degree of variability in results was observed with one participant producing 28% more urine and others ranging from 18–83% reduction in urine output during the NaCl trial. The results of this study suggest that after exercise induced dehydration, the ingestion of a 50 mmol/L NaCl solution leads to greater fluid retention compared with water, even when a meal is consumed postexercise. Furthermore, ingestion of plain water may be effective for maintenance of fluid balance when food is consumed in the rehydration period.

Acute kidney injury (AKI) incidence (diagnosed by changes in serum creatinine [Cr]) following prolonged endurance events has been reported to be anywhere from 4 to 85%, and hypohydration may contribute to this. Whilst an increase in serum Cr indicates impaired kidney function, this might be influenced by muscle damage. Therefore, the use of other AKI biomarkers which can detect renal tubular injury may be more appropriate. The long-term consequences of AKI are not well understood, but there are some potential concerns of an increased subsequent risk of chronic kidney disease (CKD). Therefore, this brief review explores the effects of exercise training/competition on novel AKI biomarkers and the potential influence of fluid intake. The increase in novel AKI biomarkers following prolonged endurance events suggests renal tubular injury. This is likely due to the long duration and relatively high exercise intensity, producing increased sympathetic tone, body temperature, hypohydration, and muscle damage. Whilst muscle damage appears to be an important factor in the pathophysiology of exercise-associated AKI, it may require coexisting hypohydration. Fluid intake seems to play a role in exercise-associated AKI, as maintaining euhydration with water ingestion during simulated physical work in the heat appears to attenuate rises in AKI biomarkers. The composition of fluid intake may also be important, as high-fructose drinks have been shown to exacerbate AKI biomarkers. However, it is yet to be seen if these findings are applicable to athletes performing strenuous exercise in a temperate environment. Additionally, further work should examine the effects of repeated bouts of strenuous exercise on novel AKI biomarkers.

Given the common view that pre-exercise nutrition/breakfast is important for performance, the present study investigated whether breakfast influences resistance exercise performance via a physiological or psychological effect. Twenty-two resistance-trained, breakfast-consuming men completed three experimental trials, consuming water-only (WAT), or semi-solid breakfasts containing 0 g/kg (PLA) or 1·5 g/kg (CHO) maltodextrin. PLA and CHO meals contained xanthan gum and low-energy flavouring (approximately 122 kJ), and subjects were told both ‘contained energy’. At 2 h post-meal, subjects completed four sets of back squat and bench press to failure at 90 % ten repetition maximum. Blood samples were taken pre-meal, 45 min and 105 min post-meal to measure serum/plasma glucose, insulin, ghrelin, glucagon-like peptide-1 and peptide tyrosine-tyrosine concentrations. Subjective hunger/fullness was also measured. Total back squat repetitions were greater in CHO (44 (sd 10) repetitions) and PLA (43 (sd 10) repetitions) than WAT (38 (sd 10) repetitions; P < 0·001). Total bench press repetitions were similar between trials (WAT 37 (sd 7) repetitions; CHO 39 (sd 7) repetitions; PLA 38 (sd 7) repetitions; P = 0·130). Performance was similar between CHO and PLA trials. Hunger was suppressed and fullness increased similarly in PLA and CHO, relative to WAT (P < 0·001). During CHO, plasma glucose was elevated at 45 min (P < 0·05), whilst serum insulin was elevated (P < 0·05) and plasma ghrelin suppressed at 45 and 105 min (P < 0·05). These results suggest that breakfast/pre-exercise nutrition enhances resistance exercise performance via a psychological effect, although a potential mediating role of hunger cannot be discounted.

PURPOSE: To determine whether the pattern of carbohydrate sports drink ingestion during prolonged sub-maximal running affects exogenous carbohydrate oxidation rates and gastrointestinal (GI) comfort. METHODS: Twelve well-trained male runners (27 ± 7 y, 67.9 ± 6.7 kg, V[Combining Dot Above]O2peak: 68 ± 7 mL·kg·min) completed two exercise trials of 100 min steady state running at 70% V[Combining Dot Above]O2peak. In each of the trials, 1 L of a 10% dextrose solution, enriched with [U-C] glucose, was consumed as either 200 mL every 20 min (CHO-20) or 50 mL every 5 min (CHO-5). Expired breath and venous blood samples were collected at rest and every 20 min during exercise. Subjective scales of GI comfort were recorded at regular intervals. RESULTS: Average exogenous carbohydrate oxidation rates were 23% higher during exercise in CHO-20 (0.38 ± 0.11 vs. 0.31 ± 0.11 g·min; P=0.017). Peak exogenous carbohydrate oxidation was also higher in CHO-20 (0.68 ± 0.14 g·min vs. 0.61 ± 0.14 g·min; P=0.004). During exercise, total carbohydrate oxidation (CHO-20: 2.15 ± 0.47; CHO-5: 2.23 ± 0.45 g·min, P=0.412) and endogenous carbohydrate oxidation (CHO-20: 1.78 ± 0.45; CHO-5: 1.92 ± 0.40 g·min; P=0.148) were not different between trials. Average serum glucose (P=0.952) and insulin (P=0.373) concentrations were not different between trials. There were no differences in reported symptoms of GI comfort and stomach bloatedness (P>0.05), with only 3% of reported scores classed as severe (>5 out of 10). CONCLUSION: Ingestion of a larger volume of carbohydrate solution at less frequent intervals during prolonged submaximal running increased exogenous carbohydrate oxidation rates. Neither drinking pattern resulted in increased markers of GI discomfort to a severe level.

Purpose Intermittent energy restriction commonly refers to ad libitum energy intake punctuated with 24 h periods of severe energy restriction. This can improve markers of metabolic health but the effects on bone metabolism are unknown. This study assessed how 24 h severe energy restriction and subsequent refeeding affected markers of bone turnover. Methods In a randomised order, 16 lean men and women completed 2, 48 h trials over 3 days. On day 1, participants consumed a 24 h diet providing 100% [EB: 9.27 (1.43) MJ] or 25% [ER: 2.33 (0.34) MJ] of estimated energy requirements. On day 2, participants consumed a standardised breakfast (08:00), followed by an ad libitum lunch (12:00) and dinner (19:30). Participants then fasted overnight, returning on day 3. Plasma concentrations of C-terminal telopeptide of type I collagen (CTX), procollagen type 1 N-terminal propeptide (P1NP) and parathyroid hormone (PTH) were assessed as indices of bone metabolism after an overnight fast on days 1–3, and for 4 h after breakfast on day 2. Results There were no differences between trials in fasting concentrations of CTX, P1NP or PTH on days 1–3 (P > 0.512). During both trials, consuming breakfast reduced CTX between 1 and 4 h (P P P = 0.773) Postprandial responses for CTX (P = 0.157), P1NP (P = 0.148) and PTH (P = 0.575) were not different between trials. Ad libitum energy intake on day 2 was greater on ER [12.62 (2.46) MJ] than EB [11.91 (2.49) MJ]. Conclusions Twenty-four hour severe energy restriction does not affect markers of bone metabolism.

Background: Few studies have investigated the effect of hydration status on appetite for food in healthy adults. Prior work suggests hydration status does not alter appetite or energy intake, with mixed findings regarding appetite hormone secretion. However, an extensive investigation into both the psychological and physiological appetitive responses to hydration status has never been conducted. Objective: To investigate the effect of hydration status on multiple facets of appetite.Design: After 3 days pre-trial standardization, a range of appetite tasks were conducted when hypohydrated (HYPO) and euhydrated (EUHY) in 16 healthy participants (8 men). Hydration status was manipulated via dehydration in a heat tent for 60 min and subsequent fluid restriction (HYPO) or replacement (EUHY). The next day, a food reward computer task was completed followed by an ad libitum pasta meal. Pre- and post-prandial visual analogue scales assessing hunger, fullness, and flavour desires (sweet, salty, savoury and fatty) were additionally completed. Blood samples were taken the previous day before the hydration interventions in a euhydrated state, and in the fasted and post-prandial state during HYPO and EUHY.Results: HYPO induced -1.9 ± 1.2% body mass change, compared to -0.2 ± 0.6%, with accompanying changes in markers of hypohydration which were not seen during EUHY. A higher desire for foods was associated with a higher water content but the association was weaker in EUHY compared to HYPO, (β= -0.33 mm/g of food water content, p < 0.001) in the food reward task. Visual analogue scales showed similar hunger and fullness between interventions, but during HYPO there was consistently higher thirst (average range in difference 27–32 mm across all time points) and lower fasted desire for salt (−23, 95% CI −10, −35 mm). Ad libitum energy intake (HYPO 1953 ± 742 kJ, EUHY 2027 ± 926 kJ; p = 0.542) and post-prandial ghrelin concentrations (HYPO 180 ± 65 pg mL−1, EUHY 188 ± 71 pg mL−1; p = 0.736) were similar by hydration status.Conclusions: An acute manipulation to hydration status altered desire for salt and foods of differing water contents, but did not influence energy intake at an ad libitum pasta meal. Further research should investigate whether these appetites would alter food choice.

Background: Chronic hot water immersion (HWI) confers health benefits, including a reduction in fasting blood glucose concentration. Here we investigate acute glycaemic control immediately after HWI. Methods: Ten participants (age: 25 ± 6 years, body mass: 84 ± 14 kg, height 1.85 ± 0.09 m) were immersed in water (39oC) to the neck (HWI) or sat at room temperature (CON) for 60 min. One hour afterwards they underwent an oral glucose tolerance test (OGTT), with blood collected before and after HWI/CON and during the 2 h OGTT. Results: Glucose incremental area under the curve (iAUC) during the OGTT was higher for HWI (HWI 233 ± 88, CON 156 ± 79 mmol·L-1·2h, P = 0.02). Insulin iAUC did not differ between conditions (HWI 4309 ± 3660, CON 3893 ± 3031 mU·L-1·2h, P=0.32). Core temperature increased to 38.6 ± 0.2°C during HWI, but was similar between trials during the OGTT (HWI 37.0 ± 0.2, CON 36.9 ± 0.4°C, P=0.34). Directly following HWI, plasma average adrenaline and growth hormone concentrations increased 2.7 and 10.7-fold, respectively (P < 0.001). Plasma glucagon like peptide-1, peptide YY and acylated ghrelin concentrations were not different between trials during the OGTT (P > 0.11). Conclusions: HWI increased postprandial glucose concentration to an OGTT, which was accompanied by acute elevations of stress hormones following HWI. The altered glycaemic control appears to be unrelated to changes in gut hormones during the OGTT.