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Background: Physiologic and psychologic stress slow healing from experimental wounds by impairing immune function.Objectives: We aimed to determine whether supplemental protein and multinutrient supplementation improved wound healing markers after acute stress induced by acute sleep restriction.Methods: In this single-blind, crossover study in generally healthy young adults (18 males/2 females; mean ± SD age: 19.7 ± 2.30 y), experimental wounds were created by removing the top layer of forearm blisters induced via suction after 48 h of 72-h sleep restriction (2-h nightly sleep), a protocol previously shown to delay wound healing. Skin barrier restoration (measured by transepidermal water loss) assessed wound healing ≤10 d postblistering, and local immune responses were evaluated by serial measurement of cytokine concentrations in fluid collected at wound sites for 48 h postblistering. Participants consumed controlled, isocaloric diets with either 0.900 g · kg-1 · d-1 protein plus placebo (PLA) or 1.50 g · kg-1 · d-1 protein plus multinutrient beverage [l-arginine: 20.0 g/d; l-glutamine: 30.0 g/d; omega-3 (n-3) fatty acids: 1.00 g/d; zinc sulfate: 24.0 mg/d; cholecalciferol: 800 IU/d; and vitamin C: 400 mg/d] (NUT) during sleep restriction and for 4 d afterwards.Results: Skin barrier restoration (primary outcome) was shorter for NUT (median: 3.98 d; IQR: 1.17 d) than for PLA (median: 5.25 d; IQR: 1.05 d) (P = 0.001). Cytokines from wound fluid (secondary outcome) increased over time (main effect of time P ≤ 0.001), except IL-13 (P = 0.07); however, no effects of treatment were observed.Conclusions: Supplemental nutrition may promote wound healing after sleep restriction in healthy adults including military personnel, the latter of which also have a high incidence of wounds and infection.This trial was registered at clinicaltrials.gov as NCT03525184. [ABSTRACT FROM AUTHOR]

Objectives: To compare heat acclimation adaptations after three and six days of either post-exercise hot water immersion (HWI) or exercise-heat-acclimation (EHA) in recreationally active individuals.Design: Randomised, mixed model, repeated measures.Methods: Post-exercise HWI involved a daily 40-min treadmill-run at 65% V̇O2peak in temperate conditions (19 °C, 45% RH) followed by HWI (≤40 min, 40 °C water; n = 9). Daily EHA involved a ≤60-min treadmill-run in the heat (65% V̇O2peak; 33 °C, 40% RH; n = 9), chosen to elicit a similar endogenous thermal stimulus to HWI. A thermoneutral exercise intervention (TNE, 19 °C, 45% RH; n = 9), work-matched to EHA, was also included to determine thermoregulatory adaptations to daily exercise in temperate conditions. An exercise-heat-stress-test was performed before and after three and six intervention days and involved a 40-min treadmill-run and time-to-exhaustion (TTE) at 65% V̇O2peak in the heat (33 °C, 40% RH).Results: ANCOVA, using baseline values as the covariate, revealed no interaction effects but significant group effects demonstrated that compared to EHA, HWI elicited larger reductions in resting rectal temperature (Tre; p = 0.021), Tre at sweating onset (p = 0.011), and end-exercise Tre during exercise-heat-stress (-0.47 °C; p = 0.042). Despite a similar endogenous thermal stimulus to HWI, EHA elicited a modest reduction in end-exercise Tre (-0.26 °C), which was not different from TNE (-0.25 °C, p = 1.000). There were no main effects or interaction effects for end-exercise Tsk, heart rate, physiological strain index, RPE, thermal sensation, plasma volume, or TTE (all p ≥ 0.154).Conclusions: Compared with conventional short-term exercise heat acclimation, short-term post-exercise hot water immersion elicited larger thermal adaptations. [ABSTRACT FROM AUTHOR]

Objective: To compare the effectiveness of a single-layered polyethylene survival bag (P), a single-layered polyethylene survival bag with a hot drink (P+HD), a multi-layered metalized plastic sheeting survival bag (MPS: Blizzard Survival), and a multi-layered MPS survival bag with 4 large chemical heat pads (MPS+HP: Blizzard Heat) to treat cold casualties.Methods: Portable cold casualty treatment methods were compared by examining core and skin temperature, metabolic heat production, and thermal comfort during a 3-hour, 0°C cold air exposure in 7 shivering, near-hypothermic men (35.4°C). The hot drink (70°C, ~400 ml, ~28 kJ) was consumed at 0, 1, and 2 hours during the cold air exposure.Results: During the cold air exposure, core rewarming and thermal comfort were similar on all trials (P = .45 and P = .36, respectively). However, skin temperature was higher (10%-13%; P < .001; large effect sizes d > 2.7) and metabolic heat production lower (15%-39%; P < .05; large effect sizes d > .9) on MPS and MPS+HP than P and P+HD. The addition of heat pads further lowered metabolic heat production by 15% (MPS+HP vs MPS; P = .05; large effect size d = .9). The addition of the hot drink to polyethylene survival bag did not increase skin temperature or lower metabolic heat production.Conclusions: Near-hypothermic cold casualties are rewarmed with less peripheral cold stress and shivering thermogenesis using a multi-layered MPS survival bag compared with a polyethylene survival bag. Prehospital rewarming is further aided by large chemical heat pads but not by hot drinks. [ABSTRACT FROM AUTHOR]

Background: The identification of beverages that promote longer-term fluid retention and maintenance of fluid balance is of real clinical and practical benefit in situations in which free access to fluids is limited or when frequent breaks for urination are not desirable. The postingestion diuretic response is likely to be influenced by several beverage characteristics, including the volume ingested, energy density, electrolyte content, and the presence of diuretic agents. Objective: This study investigated the effects of 13 different commonly consumed drinks on urine output and fluid balance when ingested in a euhydrated state, with a view to establishing a beverage hydration index (BHI), i.e., the volume of urine produced after drinking expressed relative to a standard treatment (still water) for each beverage. Design: Each subject (n = 72, euhydrated and fasted male subjects) ingested 1 L still water or 1 of 3 other commercially available beverages over a period of 30 min. Urine output was then collected for the subsequent 4 h. The BHI was corrected for the water content of drinks and was calculated as the amount of water retained at 2 h after ingestion relative to that observed after the ingestion of still water. Results: Total urine masses (mean ± SD) over 4 h were smaller than the still-water control (1337 ± 330 g) after an oral rehydration solution (ORS) (1038 ± 333 g, P < 0.001), full-fat milk (1052 ± 267 g, P < 0.001), and skimmed milk (1049 ± 334 g, P < 0.001). Cumulative urine output at 4 h after ingestion of cola, diet cola, hot tea, iced tea, coffee, lager, orange juice, sparkling water, and a sports drink were not different from the response to water ingestion. The mean BHI at 2 h was 1.54 ± 0.74 for the ORS, 1.50 ± 0.58 for full-fat milk, and 1.58 ± 0.60 for skimmed milk. Conclusions: BHI may be a useful measure to identify the short-term hydration potential of different beverages when ingested in a euhydrated state. This trial was registered at www.isrctn.com as ISRCTN13014105. [ABSTRACT FROM AUTHOR]

Universal access to information for health professionals is a prerequisite for meeting the Millennium Development Goals and achieving Health for All. However, despite the promises of the information revolution, and some successful initiatives, there is little if any evidence that the majority of health professionals in the developing world are any better informed than they were 10 years ago. Lack of access to information remains a major barrier to knowledge-based health care in developing countries. The development of reliable, relevant, usable information can be represented as a system that requires cooperation among a wide range of professionals including health-care providers, policy makers, researchers, publishers, information professionals, indexers, and systematic reviewers. The system is not working because it is poorly understood, unmanaged, and under-resourced. This Public Health article proposes that WHO takes the lead in championing the goal of “Universal access to essential health-care information by 2015” or “Health Information for All”. Strategies for achieving universal access include funding for research into barriers to use of information, evaluation and replication of successful initiatives, support for interdisciplinary networks, information cycles, and communities of practice, and the formation of national policies on health information. [Copyright &y& Elsevier]

Objective: To identify whether saliva flow rate, total protein concentration and osmolality are sensitive non-invasive markers of whole body hydration status, we compared changes in these parameters with changes in body mass during progressive acute dehydration. Design: Twelve euhydrated males reported to the laboratory following an overnight fast and cycled on a stationary ergometer at 60% maximal oxygen uptake in an environmental chamber (30 °C and 70% RH) until progressive body mass loss (BML) of 1.1±0.0, 2.0±0.0 and 2.9±0.2%. After exercise, subjects were given a volume of carbohydrate electrolyte solution equivalent to 150% BML to consume within 1 h. Unstimulated whole saliva samples were collected over a 2 min period into pre-weighed tubes at pre-exercise, 1.1, 2.0 and 2.9% BML and then at 75, 135 and 195 min post-exercise. Results: Saliva total protein concentration and osmolality increased and flow rate decreased (P<0.01) during dehydration. Saliva total protein concentration and osmolality correlated strongly with % BML during dehydration (mean r=0.97 and 0.94, respectively: P<0.01). The correlation for saliva total protein concentration with % BML was greater (P<0.05) than the correlation for saliva flow rate with % BML (mean r=−0.88: P<0.01) during dehydration. Conclusions: These data show that changes in saliva total protein concentration and osmolality, and to a lesser extent flow rate, are strongly associated with changes in body mass during progressive acute dehydration. [Copyright &y& Elsevier]

Short periods of basic military training increase the density and size of the tibia, but the adaptive response of bone microarchitecture, a key component of bone strength, is not fully understood. Tibial volumetric bone mineral density (vBMD), geometry, microarchitecture and mechanical properties were measured using high-resolution peripheral quantitative computed tomography in 43 male British Army infantry recruits (mean ± SD, age 21 ± 3 years, height 1.76 ± 0.06 m, body mass 76.5 ± 9.4 kg). Bilateral scans were performed at the distal tibia at the start (week 1) and end (week 13) of basic military training. Concurrent measures were obtained for whole-body areal bone mineral density (aBMD) using DXA, and markers of bone metabolism (βCTX, P1NP, PTH, total 25(OH)D and ACa) from venous blood. Training increased areal BMD for total body (1.4%) and arms (5.2%) (P ≤ 0.031), but not legs and trunk (P ≥ 0.094). Training increased trabecular (1.3 to 1.9%) and cortical vBMD (0.6 to 0.9%), trabecular volume (1.3 to 1.9%), cortical thickness (3.2 to 5.2%) and cortical area (2.6 to 2.8%), and reduced trabecular area (−0.4 to −0.5%) in both legs (P < 0.001). No changes in trabecular number, thickness and separation, cortical porosity, stiffness or failure load were observed (P ≥ 0.188). βCTX decreased (−0.11 μg∙l−1, P < 0.001) and total 25(OH)D increased (9.4 nmol∙l−1, P = 0.029), but no differences in P1NP, PTH or ACa were observed between timepoints (P ≥ 0.233). A short period of basic military training increased density and altered geometry of the distal tibia in male military recruits. The osteogenic effects of basic military training are likely due to an increase in unaccustomed, dynamic and high-impact loading. • We explored the effect of 13 weeks of basic military training on bone in men. • Training increased trabecular vBMD and volume, and reduced trabecular area. • Training increased cortical volumetric BMD, thickness and area. • Trabecular microarchitecture, cortical porosity and strength were unchanged. • Training reduced bone resorption, but had no effect on bone formation. [ABSTRACT FROM AUTHOR]

The influence of iron on collagen synthesis and vitamin D metabolism has implications for bone health. This cross-sectional observational study investigated associations between markers of iron status and tibial structure, vitamin D metabolites, and circulating biochemical markers of bone metabolism in young healthy men. A total of 343 male British Army recruits participated (age 22 ± 3 y, height 1.77 ± 0.06 m, body mass 75.5 ± 10.1 kg). Circulating biochemical markers of iron status, vitamin D metabolites, and bone metabolism, and tibial structure and density by high-resolution peripheral quantitative computed tomography scans (HRpQCT) were measured in participants during week 1 of basic military training. Associations between markers of iron status and HRpQCT outcomes, bone metabolism, and vitamin D metabolites were tested, controlling for age, height, lean body mass, and childhood exercise volume. Higher ferritin was associated with higher total, trabecular, and cortical volumetric bone mineral density, trabecular volume, cortical area and thickness, stiffness, and failure load (all p ≤ 0.037). Higher soluble transferrin receptor (sTfR) was associated with lower trabecular number, and higher trabecular thickness and separation, cortical thickness, and cortical pore diameter (all p ≤ 0.033). Higher haemoglobin was associated with higher cortical thickness (p = 0.043). Higher ferritin was associated with lower βCTX, PINP, total 25(OH)D, and total 24,25(OH) 2 D, and higher 1,25(OH) 2 D:24,25(OH) 2 D ratio (all p ≤ 0.029). Higher sTfR was associated with higher PINP, total 25(OH)D, and total 24,25(OH) 2 D (all p ≤ 0.025). The greater density, size, and strength of the tibia, and lower circulating concentrations of markers of bone resorption and formation with better iron stores (higher ferritin) are likely as a result of the direct role of iron in collagen synthesis. • We explored the relationship between iron status and bone structure and metabolism. • Higher ferritin was associated with higher density and size of tibial bone. • Higher ferritin was associated with lower bone resorption and formation. • Higher ferritine was associated with lower total 25(OH)D. [ABSTRACT FROM AUTHOR]

Abstract: Human hydration assessment is a key component for the prevention and proper treatment of heat-related fluid and electrolyte imbalances within military, sports and clinical medicine communities. Despite the availability of many different methods for assessing hydration status, the need for a valid method or technology that is simple, rapid, non-invasive, universal (detects both hypertonic and isotonic hypovolaemia) and is applicable for static (single point in time) and dynamic (change across time) hydration assessment is widely acknowledged. The eye is one candidate body region that might afford such a measure given the intricate balance between ocular dynamics (tear and aqueous humor formation) and blood (plasma osmolality and volume), which is considered the criterion measure for hydration assessment. The aim of this review is to introduce and discuss the potential for using ocular measurements for non-invasive hydration assessment, including tear fluid osmolarity (Tosm), non-invasive tear break-up time (NITBUT) and intraocular pressure (IOP). There is a relevant physiological basis for testing the merit of ocular measures for human hydration assessment and recent data indicate that Tosm and IOP may have utility. Further investigations are warranted to determine the degree to which ocular measures can act as accurate and reliable non-invasive hydration status markers. [Copyright &y& Elsevier]

Objectives Dehydration in older adults contributes to increased morbidity and mortality during hospitalization. As such, early diagnosis of dehydration may improve patient outcome and reduce the burden on healthcare. This prospective study investigated the diagnostic accuracy of routinely used physical signs, and noninvasive markers of hydration in urine and saliva. Design Prospective diagnostic accuracy study. Setting Hospital acute medical care unit and emergency department. Participants One hundred thirty older adults [59 males, 71 females, mean (standard deviation) age = 78 (9) years]. Measurements Participants with any primary diagnosis underwent a hydration assessment within 30 minutes of admittance to hospital. Hydration assessment comprised 7 physical signs of dehydration [tachycardia (>100 bpm), low systolic blood pressure (<100 mm Hg), dry mucous membrane, dry axilla, poor skin turgor, sunken eyes, and long capillary refill time (>2 seconds)], urine color, urine specific gravity, saliva flow rate, and saliva osmolality. Plasma osmolality and the blood urea nitrogen to creatinine ratio were assessed as reference standards of hydration with 21% of participants classified with water-loss dehydration (plasma osmolality >295 mOsm/kg), 19% classified with water-and-solute-loss dehydration (blood urea nitrogen to creatinine ratio >20), and 60% classified as euhydrated. Results All physical signs showed poor sensitivity (0%–44%) for detecting either form of dehydration, with only low systolic blood pressure demonstrating potential utility for aiding the diagnosis of water-and-solute-loss dehydration [diagnostic odds ratio (OR) = 14.7]. Neither urine color, urine specific gravity, nor saliva flow rate could discriminate hydration status (area under the receiver operating characteristic curve = 0.49–0.57, P > .05). In contrast, saliva osmolality demonstrated moderate diagnostic accuracy (area under the receiver operating characteristic curve = 0.76, P < .001) to distinguish both dehydration types (70% sensitivity, 68% specificity, OR = 5.0 (95% confidence interval 1.7–15.1) for water-loss dehydration, and 78% sensitivity, 72% specificity, OR = 8.9 (95% confidence interval 2.5–30.7) for water-and-solute-loss dehydration). Conclusions With the exception of low systolic blood pressure, which could aid in the specific diagnosis of water-and-solute-loss dehydration, physical signs and urine markers show little utility to determine if an elderly patient is dehydrated. Saliva osmolality demonstrated superior diagnostic accuracy compared with physical signs and urine markers, and may have utility for the assessment of both water-loss and water-and-solute-loss dehydration in older individuals. It is particularly noteworthy that saliva osmolality was able to detect water-and-solute-loss dehydration, for which a measurement of plasma osmolality would have no diagnostic utility. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To investigate whether unstimulated whole saliva flow rate (UFR) and osmolality (Sosm) track changes in hydration status during 48h of restricted fluid intake (RF) or combined fluid and energy restriction (RF+RE). Following the 48h periods, UFR and Sosm were assessed after acute exercise dehydration and rehydration. Design: Thirteen healthy males completed three trials in a randomised order: control (CON) where participants received their estimated energy (12,154±230kJ/d: mean±S.E.M) and fluid (3912±140ml/d) requirements, RF trial where participants received their energy requirements and 193±19ml/d water to drink (total fluid 960±15ml/d) and RF+RE where participants received 1214±25kJ/d and 962±16ml/d. After 48h, participants completed 30min of maximal exercise followed by rehydration (0–2h) and refeeding (2–6h). Results: At 48h body mass loss exceeded 3% on RF and RF+RE. UFR decreased during 48h on RF (510±122 to 169±37μl/min) and RF+RE (452±92 to 265±53μl/min) and was lower than CON at 48h (441±90μl/min: P <0.05). Sosm increased during 48h on RF (54±3 to 73±5mOsmol/kg) and RF+RE (52±3 to 68±5mOsmol/kg) and was greater than CON at 48h (52±2mOsmol/kg: P <0.05). Unlike UFR, Sosm identified the additional hypohydration associated with exercise (P <0.05) and returned to within 0h values with rehydration. Conclusions: Sosm, and to a lesser extent UFR, track hydration status during a 48h period of RF or RF+RE and after subsequent exercise and rehydration. [Copyright &y& Elsevier]