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This study aimed to determine whether caffeine gum influenced perceptual-cognitive and physical performance during the extra-time period of simulated soccer match-play. Semiprofessional male soccer players (n = 12, age: 22 ± 3 years, stature: 1.78 ± 0.06 m, mass: 75 ± 9 kg) performed 120-min soccer-specific exercise on two occasions. In a triple-blind, randomized, crossover design, players chewed caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum for 5 min following 90 min of soccer-specific exercise. Perceptual-cognitive skills (i.e., passing accuracy, reaction time, composure, and adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and posttrial. Neuromuscular performance (reactive-strength index, vertical jump height, absolute and relative peak power output, and negative vertical displacement) and sprint performance (15 and 30 m) were measured at pretrial, half-time, 90 min, and posttrial. Caffeine gum attenuated declines in reaction time (pre: 90.8 ± 0.8 AU to post: 90.7 ± 0.8 AU) by a further 4.2% than placebo (pre: 92.1 ± 0.8 AU to post: 88.2 ± 0.8 AU; p <.01). Caffeine gum reduced composure by 4.7% (pre: 69.1 ± 0.8 AU to post: 65.9 ± 0.8 AU) versus placebo (pre: 68.8 ± 0.8 AU to post: 68.3 ± 0.8 AU; p <.01). Caffeine gum did not influence any other variables (p >.05). Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and neuromuscular and sprint performance remain unchanged. Future work should assess caffeine gum mixes with substances like L-theanine that promote a relaxed state under stressful conditions. [ABSTRACT FROM AUTHOR]

Background: Despite enhanced recovery programmes, length of stay is variable following robotic assisted radical cystectomy (RARC). The aim of this study was to assess the impact socioeconomic deprivation on recovery following RARC. Methods: The prospectively maintained RARC databases at two tertiary referral hospitals were reviewed from 2015 to 2017. Demographic, histological, and outcome data including length of stay (LOS), operation time and blood loss were recorded. The Index of Multiple Deprivation, was chosen as a deprivation index as this is used by the UK government to direct funding and resources to regions, towns and postal codes by assessing a number of indicators. Results: During the study period, 340 consecutive patients underwent RARC. Deprivation deciles were significantly higher in site 1 patients (7.9 in site 1 vs 6.6 in site 2, p < 0.001) implying that these patients are more likely to have higher incomes, levels of education and improved living environments. The mean operating time was longer in the site 1 cohort (397 vs 366 min, p > 0.001) with a reduced mean blood loss volume (252 and 484 mL, p < 0.001). There was a significant difference in mean LOS (6.2 days in site 1 vs 10.6 days in site 2, p < 0.001). On multivariable analysis, a higher deprivation decile did not predict LOS (OR = 1, 95% CI = 0.9–1.1, p = 0.407). Sex and operation site were however significantly associated with LOS (p = 0.006 and <0.001). Conclusion: Recovery following RARC was independent of socioeconomic status when comparing two hospitals with diverse catchment areas in the UK. [ABSTRACT FROM AUTHOR]

Postpartum haemorrhage continues to be a leading cause of morbidity and mortality in the obstetric population worldwide, especially in patients at extremes of body weight. Quantification of blood loss has been considered extensively in the literature. However, these volumes must be contextualised to appreciate the consequences of blood loss for individual parturients. Knowledge of a patient's peripartum circulating blood volume is essential to allow accurate interpretation of the significance of haemorrhage and appropriate resuscitation. Greater body weight in obesity can lead to overestimation of blood volume, resulting in inappropriately high thresholds for blood product transfusion and delays in treatment. The most recent Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries across the UK (MBRRACE-UK) surveillance report demonstrated the risk to this population, with more than half of all maternal mortality recorded in parturients who were either overweight or obese. Current linear calculations used to estimate circulating blood volumes based on patients' weights could be contributing to this phenomenon, as blood volume increases at a disproportional rate to body composition. In this review, we summarise the relevant physiology and explore the existing literature on the estimation of circulating blood volume, both during pregnancy and in obesity. Building on key works and principal findings, we present a practical, nonlinear approach to the adjustment of estimated blood volume with increasing body mass. This clinical tool aims to reduce the clinical bias influencing the management of obstetric haemorrhage in a population already at increased risk of morbidity and mortality. Discussion of the limitations of this approach and the call for further research within this field completes this review. [ABSTRACT FROM AUTHOR]

Summary: Low platelet count, or thrombocytopenia, is a common haematological abnormality, with a wide differential diagnosis, which may represent a clinically significant underlying pathology. Macrothrombocytopenia, the presence of large platelets in combination with thrombocytopenia, can be acquired or hereditary and indicative of a complex disorder. In this review, we discuss the interpretation of platelet count and volume measured by automated haematology analysers and highlight some important technical considerations relevant to the analysis of blood samples with macrothrombocytopenia. We review how large cohorts, such as the UK Biobank and INTERVAL studies, have enabled an accurate description of the distribution and co‐variation of platelet parameters in adult populations. We discuss how genome‐wide association studies have identified hundreds of genetic associations with platelet count and mean platelet volume, which in aggregate can explain large fractions of phenotypic variance, consistent with a complex genetic architecture and polygenic inheritance. Finally, we describe the large genetic diagnostic and discovery programmes, which, simultaneously to genome‐wide association studies, have expanded the repertoire of genes and variants associated with extreme platelet phenotypes. These have advanced our understanding of the pathogenesis of hereditary macrothrombocytopenia and support a future clinical diagnostic strategy that utilises genotype alongside clinical and laboratory phenotype data. [ABSTRACT FROM AUTHOR]

Purpose: Individuals with a spinal-cord injury have impaired thermoregulatory control due to a loss of sudomotor and vasomotor effectors below the lesion level. Thus, individuals with high-level lesions (tetraplegia) possess greater thermoregulatory impairment than individuals with lower-level lesions (paraplegia). Previous research has not reflected the intermittent nature and modality of wheelchair court sports or replicated typical environmental temperatures. Hence, the purpose of this study was to investigate the thermoregulatory responses of athletes with tetraplegia and paraplegia during an intermittent-sprint protocol (ISP) and recovery in cool conditions. Methods: Sixteen wheelchair athletes, 8 with tetraplegia (TP, body mass 65.2 ± 4.4 kg) and 8 with paraplegia (body mass 68.1 ± 12.3 kg), completed a 60-min ISP in 20.6°C ± 0.1°C, 39.6% ± 0.8% relative humidity on a wheelchair ergometer, followed by 15 min of passive recovery. Core temperature (Tcore) and mean (Tsk) and individual skin temperatures were measured throughout. Results: Similar external work (P = .70, ES = 0.20) yet a greater Tcore (P < .05, ES = 2.27) and Tsk (P < .05, ES = 1.50) response was demonstrated by TP during the ISP. Conclusions: Despite similar external work, a marked increase in Tcore in TP during exercise and recovery signifies that thermoregulatory differences between the groups were predominantly due to differences in heat loss. Further increases in thermal strain were not prevented by the active and passive recovery between maximal-effort bouts of the ISP, as Tcore continually increased throughout the protocol in TP. [ABSTRACT FROM AUTHOR]

background: UK Royal Air Force fast jet aircrew use three different anti-G systems, however, little objective comparison of the G protection they provide exists. The G-protection afforded by each system and associated hemodynamic responses were investigated. METHODS: Ten subjects performed centrifuge acceleration exposures using Mk-10 (SI) and Mk-4 (S2) five-bladder anti-G trousers (AGT) and full coverage AGT plus pressure breathing for G-protection (PBG; S3). Measurements of relaxed G tolerance (RGT), eye-level blood pressure (BPeye), lower body blood volume (LBV), stroke volume (SV) and total peripheral resistance (TPR) were made during gradual onset runs (GOR) and rapid onset runs (ROR). The subjective effort required to maintain clear vision at +7 and +8 Gz provided an indication of the protection provided by the system. RESULTS: All systems moderated decreases in SV and BPeye and increases in LBV under increased +GZ. S3 provided the greatest mean RGT during GOR (+6.2 Gz) and ROR (+6 Gz), reduced the effort required to maintain clear vision at up to +8 Gz, prevented venous pooling and afforded the greatest rise in TPR. The majority of indices revealed no difference between S1 and S2 although RGT during the ROR was greater with S2 (+0.25 Gz). DISCUSSION: S3 effectively prevented pooling of blood in the lower limbs under +GZ, despite the use of PBG, and offers an advantage over five-bladder AGT. Given the similarities of S1 and S2, it was unsurprising that the majority of indices measured were similar. The objective measurement of hemodynamic parameters provides useful information for comparing the G-protection provided by anti-G systems. [ABSTRACT FROM AUTHOR]

Myokines may play a role in the health benefits of regular physical activity. Secreted protein acidic rich in cysteine (SPARC) is a pleiotropic myokine that has been shown to be released into the bloodstream by skeletal muscle in response to aerobic exercise. As there is evidence suggesting that SPARC release may be linked to glycogen breakdown and activation of 5’ adenosine monophosphate-activated protein kinase, we hypothesised that brief supramaximal exercise may also be associated with increased serum SPARC levels. In the present study, 10 participants (3 women; mean ± SD age: 21 ± 3 y, body mass index (BMI): 22 ± 3 kg m−2, and V˙O2max: 39 ± 6 mL kg−1 min−1) performed an acute bout of supramaximal cycle exercise (20-s Wingate sprint against 7.5% of body mass, with a 1-min warm-up and a 3-min cool-down consisting of unloaded cycling). Serum SPARC levels were determined pre-exercise as well as 0, 15, and 60 min post-exercise and corrected for plasma volume change. To determine whether regular exercise affected the acute SPARC response, participants repeated the acute exercise protocol three times per week for four weeks, and serum SPARC response to supramaximal exercise was reassessed after this period. Acute supramaximal exercise significantly decreased plasma volume (−10%;p < .001), but was not associated with a significant change in serum SPARC levels at either the pre-training or post-training testing sessions. In conclusion, in contrast to aerobic exercise, a single brief supramaximal cycle sprint is not associated with an increase in serum SPARC levels, suggesting that SPARC release is not related to skeletal muscle glycogen breakdown. [ABSTRACT FROM PUBLISHER]

Purpose: This investigation quantified the effect of changes in plasma osmolality on the measurement of hematocrit (Hct) and the implications for the subsequent use of these data to calculate changes in plasma volume and application to the World Anti-Doping Agency Athlete Biological Passport. Methods: Two groups of eight male volunteers visited the laboratory after an overnight fast. In study 1, a 20-mL blood sample was collected and aliquoted into collection tubes containing saline of varying concentrations to alter the sample osmolality. In study 2, plasma osmolality was manipulated in vivo through prolonged exercise. Samples were analyzed for hemoglobin concentration and Hct using manual methods and using an automated hematology analyzer (AHA). Results: Changes in blood, plasma, and red cell volumes were calculated. Although AHA Hct values did not change (P = 0.652), spun packed cell volume fell progressively as the osmolality of the sample increased (P < 0.001, study 1). Consequently, there was a significant increase in apparent plasma volume as osmolality increased (P < 0.001): regression analysis revealed that a 10 mOsm⋅kg-1 change in plasma osmolality produced a difference of 0.8 Hct units and a 1.6% change in plasma volume. In study 2, exercise produced a 12 ± 3 mOsm⋅kg-1 increase in plasma osmolality. No difference in Hct was apparent at rest (P = 0.659), but spun packed cell volume was 1.0 ± 0.9 Hct units lower during exercise compared with AHA data (P < 0.001). There was a difference in the degree of plasma volume change calculated, with a reduction of 8.7% ± 3.4% and 11.3% ± 3.5% reported with the manual and AHA methods, respectively (P = 0.002). Conclusions: Conditions or interventions that result in a marked change in plasma osmolality produce a discrepancy in Hct measured using an AHA, consequently introducing errors into any calculation of changes in plasma volume using these data. These findings may also have implications for the measurement of Hct by World Anti-Doping Agency-accredited laboratories. [ABSTRACT FROM AUTHOR]

Purpose: Acute antioxidant supplementation may modulate oxidative stress and some immune perturbations that typically occur following prolonged exercise. The aims of the present study were to examine the effects of acutely consuming dark chocolate (high polyphenol content) on plasma antioxidant capacity, markers of oxidative stress and immunoendocrine responses to prolonged exercise. Methods: Fourteen healthy men cycled for 2.5 h at ~60% maximal oxygen uptake 2 h after consuming 100 g dark chocolate (DC), an isomacronutrient control bar (CC) or neither (BL) in a randomised-counterbalanced design. Results: DC enhanced pre-exercise antioxidant status ( P = 0.003) and reduced by trend ( P = 0.088) 1 h post-exercise plasma free [F-isoprostane] compared with CC (also, [F-isoprostane] increased post-exercise in CC and BL but not DC trials). Plasma insulin concentration was significantly higher pre-exercise ( P = 0.012) and 1 h post-exercise ( P = 0.026) in the DC compared with the CC trial. There was a better maintenance of plasma glucose concentration on the DC trial (2-way ANOVA trial × time interaction P = 0.001), which decreased post-exercise in all trials but was significantly higher 1 h post-exercise ( P = 0.039) in the DC trial. There were no between trial differences in the temporal responses (trial × time interactions all P > 0.05) of hypothalamic-pituitary-adrenal axis stress hormones, plasma interleukin-6, the magnitude of leukocytosis and neutrophilia and changes in neutrophil function. Conclusion: Acute DC consumption may affect insulin, glucose, antioxidant status and oxidative stress responses, but has minimal effects on immunoendocrine responses, to prolonged exercise. [ABSTRACT FROM AUTHOR]

The article discusses the study on the effects of exercise and heat-induced hypohydration on the brain volume in Great Britain. It states that the aim of the study is to measure the changes of the brain volume after an exercise and heat-induced hypohydration. the study were conducted on eight active men in which they completed an intermittent exercise on a warm environment. It notes that the during the preexercise levels, the serum osmolality increased throughout the postexercise period. It also mentions that the brain volumes remains unaltered in response to moderate hypohydration of the serum hyperosmolality.

Abstract: Cardiac disease continues to be an important cause of maternal morbidity and mortality and is now the leading cause of maternal deaths in the United Kingdom. This is largely because of extensive haemodynamic changes which occur during pregnancy, namely the increase in blood volume, fluctuations in cardiac output, fall in systemic vascular resistance and hypercoagulable state. High risk periods include the end of the second trimester, during labour and the immediate postpartum period. Prognosis depends on the specific cardiac condition, the patient''s functional class, presence of cyanosis, prior history of cardiac events or arrhythmia and the degree of systolic dysfunction. Conditions where pregnancy should be include Eisenmenger''s syndrome, pulmonary hypertension, complex cyanotic congenital heart disease, Marfan syndrome with aortic root dilatation and those with severe left ventricular dysfunction. Women with heart disease should be thoroughly evaluated and counselled before and during pregnancy. Multidisciplinary care is essential for successful maternal and foetal outcomes. [Copyright &y& Elsevier]

Heat acclimation induces adaptations that improve exercise tolerance in hot conditions. Here we report novel findings into the effects of ultra-marathon specific exercise load in increasing hot ambient conditions on indices of heat acclimation. Six male ultra-endurance runners completed a standard pre-acclimation protocol at 20°C ambient temperature (Tamb), followed by a heat acclimation protocol consisting of six 2 h running exercise-heat exposures (EH) at 60%O2maxon a motorised treadmill in an environmental chamber. Three EH were performed at 30°CTamb, followed by another three EH at 35°CTamb. EH were separated by 48 h withinTamband 72 h betweenTamb. Nude body mass (NBM), blood and urine samples were collected pre-exercise; while NBM and urine were collected post-exercise. Rectal temperature (Tre), heart rate (HR), thermal comfort rating (TCR) and rating of perceived exertion were measured pre-exercise and monitored every 5 min during exercise. Water was provided ad libitum during exercise. Data were analysed using a repeated measures and one-way analysis of variance (ANOVA), with post hoc Tukey's HSD. Significance was accepted asP< 0.05. Overall meanTrewas significantly lower during 30°C EH3 and 35°C EH3 compared with their respective EH1 (−0.20 and−0.23°C, respectively;P<0.05). Similarly, overall mean HR was significantly lower during 30°C EH3 and 35°C EH3 compared with their respective EH1 (8 and 7 bpm respectively;P<0.05). A significant decrease in overall mean TCR was observed during 35°C EH3, compared with 35°C EH1 (P<0.05). Significant increases in resting pre-exercise plasma volume (estimated from Hb and Hct) were observed by 30°C EH3 (7.9%;P<0.05). Thereafter, plasma volume remained above baseline throughout the experimental protocol. Two EH of 2 h at 60%O2maxat 30°CTambwas sufficient to initiate heat acclimation in all ultra-endurance runners. Further, heat acclimation responses occurred with increasing EH to 35°CTamb. Preventing exertional heat illnesses and optimising performance outcomes in ultra-endurance runners may occur with exposure to at least 2 h of exercise-heat stress on at least two occasions in the days leading up to multi-stage ultra-marathon competition in the heat. [ABSTRACT FROM AUTHOR]