scholarly journals Sports Dietitians Australia Position Statement: Nutrition for Exercise in Hot Environments

2020 ◽  
Vol 30 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Alan J. McCubbin ◽  
Bethanie A. Allanson ◽  
Joanne N. Caldwell Odgers ◽  
Michelle M. Cort ◽  
Ricardo J.S. Costa ◽  
...  
Keyword(s):  
Heat Stress ◽  
Thermal Sensation ◽  
Position Statement ◽  
Fluid Replacement ◽  
Population Groups ◽  
Nutritional Needs ◽  
And Performance ◽  
Hot Environments ◽  
Ultra Endurance ◽  
Exertional Heat Stress

It is the position of Sports Dietitians Australia (SDA) that exercise in hot and/or humid environments, or with significant clothing and/or equipment that prevents body heat loss (i.e., exertional heat stress), provides significant challenges to an athlete’s nutritional status, health, and performance. Exertional heat stress, especially when prolonged, can perturb thermoregulatory, cardiovascular, and gastrointestinal systems. Heat acclimation or acclimatization provides beneficial adaptations and should be undertaken where possible. Athletes should aim to begin exercise euhydrated. Furthermore, preexercise hyperhydration may be desirable in some scenarios and can be achieved through acute sodium or glycerol loading protocols. The assessment of fluid balance during exercise, together with gastrointestinal tolerance to fluid intake, and the appropriateness of thirst responses provide valuable information to inform fluid replacement strategies that should be integrated with event fuel requirements. Such strategies should also consider fluid availability and opportunities to drink, to prevent significant under- or overconsumption during exercise. Postexercise beverage choices can be influenced by the required timeframe for return to euhydration and co-ingestion of meals and snacks. Ingested beverage temperature can influence core temperature, with cold/icy beverages of potential use before and during exertional heat stress, while use of menthol can alter thermal sensation. Practical challenges in supporting athletes in teams and traveling for competition require careful planning. Finally, specific athletic population groups have unique nutritional needs in the context of exertional heat stress (i.e., youth, endurance/ultra-endurance athletes, and para-sport athletes), and specific adjustments to nutrition strategies should be made for these population groups.

scholarly journals Nutrition in Ultra-Endurance: State of the Art

Nutrients ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1995 ◽  
Author(s):  
Pantelis Nikolaidis ◽  
Eleftherios Veniamakis ◽  
Thomas Rosemann ◽  
Beat Knechtle
Keyword(s):  
Energy Balance ◽  
Negative Energy ◽  
Energy Deficit ◽  
Endurance Sports ◽  
Increased Risk ◽  
Gastrointestinal Discomfort ◽  
And Performance ◽  
Hot Environments ◽  
Ultra Endurance ◽  
Nutritional Strategies

Athletes competing in ultra-endurance sports should manage nutritional issues, especially with regards to energy and fluid balance. An ultra-endurance race, considered a duration of at least 6 h, might induce the energy balance (i.e., energy deficit) in levels that could reach up to ~7000 kcal per day. Such a negative energy balance is a major health and performance concern as it leads to a decrease of both fat and skeletal muscle mass in events such as 24-h swimming, 6-day cycling or 17-day running. Sport anemia caused by heavy exercise and gastrointestinal discomfort, under hot or cold environmental conditions also needs to be considered as a major factor for health and performance in ultra-endurance sports. In addition, fluid losses from sweat can reach up to 2 L/h due to increased metabolic work during prolonged exercise and exercise under hot environments that might result in hypohydration. Athletes are at an increased risk for exercise-associated hyponatremia (EAH) and limb swelling when intake of fluids is greater than the volume lost. Optimal pre-race nutritional strategies should aim to increase fat utilization during exercise, and the consumption of fat-rich foods may be considered during the race, as well as carbohydrates, electrolytes, and fluid. Moreover, to reduce the risk of EAH, fluid intake should include sodium in the amounts of 10–25 mmol to reduce the risk of EAH and should be limited to 300–600 mL per hour of the race.

scholarly journals Simple And Complex Cognitive Functions Under Exertional Heat Stress

2015 ◽  
Vol 16 (1) ◽  
pp. 21-25
Author(s):  
Jelena Maric ◽  
Milan Marjanovic ◽  
Dalibor Jovanovic ◽  
Filip Stojanovic ◽  
Djordje Vukmirovic ◽  
...  
Keyword(s):  
Heat Stress ◽  
Reaction Time ◽  
Cognitive Performance ◽  
Cognitive Functions ◽  
Stress Tests ◽  
Physical Strain ◽  
Spatial Part ◽  
Hot Environments ◽  
The Military ◽  
Exertional Heat Stress

ABSTRACTHeat stress is a significant problem in the military services. This study investigated the effects of exertional heat stress on cognitive performance.Forty unacclimated male soldiers performed exertional heat stress tests in cool (20 °C) and hot environments (40 °C). Cognitive performance was assessed using a computerized battery before and immediately after tests. Physical strain in cool conditions induced mild but significant deficits in accuracy in complex tests. The number of correct answers in the Matching to Sample Visual Search was reduced (92,18% correct answers before vs. 88,64 after; p<0,05) and also in the spatial part of the Pattern and Spatial Recognition Memory Test (85,25 vs. 8,75%; p<0,05). These decreases were more pronounced in hot conditions (92,38 vs. 84,31% in before and 84,21 vs. 73,42% in the latter test; ps<0,01 and <0,001, respectively). Exertional heat stress also impaired more simple cognitive functions. A significant decrease in accuracy (95,74 vs. 93,89%) and an increase in reaction time (300,32 vs. 315,00 ms) was observed in the Reaction Time test.Strenuous physical activity in a hot environment induces mild cognitive deficits, especially in more complex tasks.

EFFECTS OF INONIZING RADIATION CAUSED HEAT STRESS ON THE HUMAN BODY FOR STANDARD ISO 7243

2013 ◽  
pp. 47-57
Author(s):  
Van Trong Le ◽  
Thi Tuyet Mai Nguyen ◽  
Thi Xuan Duyen Nguyen ◽  
Ba Luan Nguyen ◽  
Tuyen Pham ◽  
...  
Keyword(s):  
Heat Stress ◽  
Risk Assessments ◽  
Management Systems ◽  
Temperature Index ◽  
Wet Bulb Globe Temperature ◽  
Simple Index ◽  
Simple Tool ◽  
Results Management ◽  
Globe Temperature ◽  
Hot Environments

Objectives: Presents heat stress Standard ISO 7243, which is based upon the wet bulb globe temperature index (WBGT), and considers its suitability for use worldwide. Materials and Methods: The WBGT index are considered and how it is used in ISO 7243 and across the world as a simple index for monitoring and assessing hot environments. Results: Management systems, involving risk assessments, that take account of context and culture, are required to ensure successful use of the standard and global applicability. For use outdoors, a WBGT equation that includes solar absorptivity is recommended. A ‘clothed WBGT’ is proposed to account for the effects of clothing. Conclusion: ISO 7243 is a simple tool to assess the heat stress and may be applicated worldwide.

scholarly journals Effects of cooled floor pads combined with chilled drinking water on behavior and performance of lactating sows under heat stress

2021 ◽  
Vol 99 (3) ◽  
Author(s):  
Y Zhu ◽  
L J Johnston ◽  
M H Reese ◽  
E S Buchanan ◽  
J E Tallaksen ◽  
...  
Keyword(s):  
Drinking Water ◽  
Heat Stress ◽  
Respiration Rate ◽  
Rectal Temperature ◽  
Time Budget ◽  
Video Recording ◽  
Lactating Sows ◽  
Before And After ◽  
And Performance ◽  
Drinking Frequency

Abstract This study was conducted to evaluate whether cooled floor pads combined with chilled drinking water could alleviate negative impacts of heat stress on lactating sows. Thirty sows (Landrace × Yorkshire, Parity = 1 to 6) were housed in individual farrowing stalls in two rooms with temperatures being controlled at 29.4°C (0700–1900 hours) and 23.9°C (1900–0700 hours). Sows in one room (Cool), but not in the other room (Control) were provided cooled floor pads (21–22°C) and chilled drinking water (13–15°C). Behavior of sows (15 sows/treatment) was video recorded during farrowing, and days 1, 3, 7, 14, and 21 after farrowing. Videos were viewed continuously to register the birth time of each piglet, from which total farrowing duration and birth intervals were calculated. The number of drinking bouts and the duration of each drinking bout were registered for each sow through viewing videos continuously for 2 h (1530–1730 hours) each video-recording day. Postures (lying laterally, lying ventrally, sitting, and standing) were recorded by scanning video recordings at 5-min intervals for 24 h each video-recording day, and time budget for each posture was calculated. Rectal temperature and respiration rate were measured for all sows the day before and after farrowing, and then once weekly. Sow and litter performance was recorded. Data were analyzed using the Glimmix procedure of SAS. The cooling treatment did not affect sow behavior or litter performance. Sows in the Cool room had lower rectal temperature (P = 0.03) and lower respiration rate (P &lt; 0.001), consumed more feed (P = 0.03), tended to have reduced weight loss (P = 0.07), and backfat loss (P = 0.07) during lactation than sows in the Control room. As lactation progressed, sows increased drinking frequency (P &lt; 0.001) and time spent lying ventrally (P &lt; 0.0001), standing (P &lt; 0.001), and sitting (P &lt; 0.0001), and decreased time spent lying laterally (P &lt; 0.0001) in both Cool and Control rooms. While cooled floor pads combined with chilled drinking water did not affect sow behavior, they did alleviate heat stress partially, as indicated by decreased rectal temperature, respiration rate, weight, and backfat loss, and increased feed intake in lactating sows.

scholarly journals The tepary bean genome provides insight into evolution and domestication under heat stress

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Samira Mafi Moghaddam ◽  
Atena Oladzad ◽  
Chushin Koh ◽  
Larissa Ramsay ◽  
John P. Hart ◽  
...  
Keyword(s):  
Heat Stress ◽  
Common Bean ◽  
Sonoran Desert ◽  
Climate Adaptation ◽  
Human Consumption ◽  
Disease Resistance Gene ◽  
Gene Repertoire ◽  
Tepary Bean ◽  
Hot Environments ◽  
Insight Into

AbstractTepary bean (Phaseolus acutifolis A. Gray), native to the Sonoran Desert, is highly adapted to heat and drought. It is a sister species of common bean (Phaseolus vulgaris L.), the most important legume protein source for direct human consumption, and whose production is threatened by climate change. Here, we report on the tepary genome including exploration of possible mechanisms for resilience to moderate heat stress and a reduced disease resistance gene repertoire, consistent with adaptation to arid and hot environments. Extensive collinearity and shared gene content among these Phaseolus species will facilitate engineering climate adaptation in common bean, a key food security crop, and accelerate tepary bean improvement.

scholarly journals Concussion in para sport: the first position statement of the Concussion in Para Sport (CIPS) Group

2021 ◽  
pp. bjsports-2020-103696
Author(s):  
Richard Weiler ◽  
Cheri Blauwet ◽  
David Clarke ◽  
Kristine Dalton ◽  
Wayne Derman ◽  
...  
Keyword(s):  
Consensus Statement ◽  
Assessment Tool ◽  
Return To Sport ◽  
Position Statement ◽  
Assessment Tools ◽  
Future Research ◽  
Concussion Management ◽  
Rule Changes ◽  
Specific Rule ◽  
And Performance

Concussion is a frequent injury in many sports and is also common in para athletes. However, there is a paucity of concussion research related to para sport, and prior International Concussion in Sport (CIS) consensus papers have not substantively addressed this population. To remedy this and to improve concussion care provided to para athletes, the concussion in para sport (CIPS) multidisciplinary expert group was created. This group analysed and discussed in-depth para athlete-specific issues within the established key clinical domains of the current (2017) consensus statement on CIS. Due to the onset of the COVID-19 pandemic, the group held all meetings by video conferencing. The existing Sport Concussion Assessment Tool 5 (SCAT5) for the immediate on-field and office-based off-field assessment of concussion was evaluated as part of this process, to identify any para athlete-specific concerns. Regular preparticipation and periodic health examinations are essential to determine a baseline reference point for concussion symptoms but pose additional challenges for the interpreting clinician. Further considerations for concussion management for the para athlete are required within the remove, rest, reconsider and refer consensus statement framework. Considering return to sport (RTS), the 2017 CIS consensus statement has limitations when considering the RTS of the para athlete. Case-by-case decision making related to RTS following concussion is imperative for para athletes. Additional challenges exist for the evaluation and management of concussion in para athletes. There is a need for greater understanding of existing knowledge gaps and attitudes towards concussion among athlete medical staff, coaches and para athletes. Future research should investigate the use and performance of common assessment tools in the para athlete population to better guide their clinical application and inform potential modifications. Concussion prevention strategies and sport-specific rule changes, such as in Para Alpine Skiing and Cerebral Palsy Football, also should be carefully considered to reduce the occurrence of concussion in para athletes.

scholarly journals Bacillus subtilis-Based Probiotic Improves Skeletal Health and Immunity in Broiler Chickens Exposed to Heat Stress

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1494
Author(s):  
Sha Jiang ◽  
Fei-Fei Yan ◽  
Jia-Ying Hu ◽  
Ahmed Mohammed ◽  
Heng-Wei Cheng
Keyword(s):  
Bacillus Subtilis ◽  
Heat Stress ◽  
Broiler Chickens ◽  
Heat Waves ◽  
Stress Sensitivity ◽  
Current Data ◽  
Negative Effects ◽  
Skeletal Health ◽  
Welfare Issue ◽  
And Performance

The elevation of ambient temperature beyond the thermoneutral zone leads to heat stress, which is a growing health and welfare issue for homeothermic animals aiming to maintain relatively constant reproducibility and survivability. Particularly, global warming over the past decades has resulted in more hot days with more intense, frequent, and long-lasting heat waves, resulting in a global surge in animals suffering from heat stress. Heat stress causes pathophysiological changes in animals, increasing stress sensitivity and immunosuppression, consequently leading to increased intestinal permeability (leaky gut) and related neuroinflammation. Probiotics, as well as prebiotics and synbiotics, have been used to prevent or reduce stress-induced negative effects on physiological and behavioral homeostasis in humans and various animals. The current data indicate dietary supplementation with a Bacillus subtilis-based probiotic has similar functions in poultry. This review highlights the recent findings on the effects of the probiotic Bacillus subtilis on skeletal health of broiler chickens exposed to heat stress. It provides insights to aid in the development of practical strategies for improving health and performance in poultry.

Increased Air Velocity Reduces Thermal and Cardiovascular Strain in Young and Older Males during Humid Exertional Heat Stress

2015 ◽  
Vol 12 (9) ◽  
pp. 625-634 ◽  
Author(s):  
Heather E. Wright Beatty ◽  
Stephen G. Hardcastle ◽  
Pierre Boulay ◽  
Andreas D. Flouris ◽  
Glen P. Kenny
Keyword(s):  
Heat Stress ◽  
Air Velocity ◽  
Exertional Heat Stress ◽  
Cardiovascular Strain ◽  
Older Males

scholarly journals Effects of Heat Stress on Gut-Microbial Metabolites, Gastrointestinal Peptides, Glycolipid Metabolism, and Performance of Broilers

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1286
Author(s):  
Guangju Wang ◽  
Xiumei Li ◽  
Ying Zhou ◽  
Jinghai Feng ◽  
Minhong Zhang
Keyword(s):  
Heat Stress ◽  
Average Daily Gain ◽  
Resistance Index ◽  
Production Performance ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Microbial Metabolites ◽  
Glycolipid Metabolism ◽  
Gastrointestinal Peptides ◽  
And Performance

This paper investigated the effects of heat stress on gut-microbial metabolites, gastrointestinal peptides, glycolipid metabolism, and performance of broilers. Thus, 132 male Arbor Acres broilers, 28-days-old, were randomly distributed to undergo two treatments: thermoneutral control (TC, 21 °C) and high temperature (HT, 31 °C). The results showed that the average daily gain (ADG), average daily feed intake (ADFI), and gastric inhibitory polypeptide (GIP) concentration in the jejunum significantly decreased the core temperature, feed conversion ratio (FCR), and ghrelin of the hypothalamus, and cholecystokinin (CCK) in jejunum, and serum significantly increased in the HT group (p < 0.05). Exploration of the structure of cecal microbes was accomplished by sequencing 16S rRNA genes. The sequencing results showed that the proportion of Christensenellaceae and Lachnospiraceae decreased significantly whereas the proportion of Peptococcaceae increased at the family level (p < 0.05). Ruminococcus and Clostridium abundances significantly increased at the genus level. Furthermore, the content of acetate in the HT group significantly increased. Biochemical parameters showed that the blood glucose concentration of the HT group significantly decreased, and the TG (serum triglycerides), TC (total cholesterol), insulin concentration, and the insulin resistance index significantly increased. Nonesterified fatty acid (NEFA) in the HT group decreased significantly. In conclusion, the results of this paper suggest that the poor production performance of broilers under heat stress may be related to short-chain fatty acids (SCFAs) fermented by intestinal microbiota involved in regulating metabolic disorders.

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