Nutrition in ultra-endurance racing - aspects of energy balance, fluid balance and exercise-associated hyponatremia

Ultra-endurance athletes try to extend their limits in performance. In ultra-endurance races, athletes face limits in nutrition regarding both energy intake and fluid metabolism. The purpose of this review is to focus on the decrease in body mass, aspects of energy and fluid balance, and exercise-associated hyponatremia in ultra-endurance performance. An ultra-endurance performance lasting 24 hours or longer may lead to an energy deficit of approximately 7,000 kcal per day. This energy deficit may result in a decrease of body mass, including a decrease in both fat mass and skeletal muscle mass. The energy deficit cannot be completely compensated by increasing energy intake. Adequate fluid intake is required during an ultra-endurance performance to prevent dehydration. In case of fluid overload, both exercise-associated hyponatremia and swelling of limbs may occur. Limited fluid intake of approximately 300-400 ml per hour may prevent both exercise-associated hyponatremia and swelling of limbs. In summary, in ultra-endurance performances, an energy deficit seems to be unavoidable, and athletes are at risk to develop both exercise-associated hyponatremia and limb swelling in case of fluid overload

Characterization of energy expenditure and body composition in military personnel during a cold field training exercise

The purpose of the following study was to re-address the energy requirements of Canadian Armed Forces (CAF) during training in a cold winter environment. Twenty CAF personnel were recruited to participate in a 5-day winter training exercise at Canadian Forces Base Meaford in Ontario, Canada. Energy expenditure (n=10) and body composition (n=14) were measured via the doubly labelled water (DLW) method and the deuterium isotope dilution technique, respectively. Mean total daily energy expenditure (TDEE) was 4900±693 kcal·day-1 with no significant differences observed between sexes. Body mass and body composition of CAF personnel changed significantly (p < 0.05) across the 5-day exercise. This decrease was associated with a significant (p < 0.05) reduction in fat mass. Despite these losses, participants were able to maintain high physical activity level (PAL) values (2.6) and high TDEE levels throughout the study period. It is recommended to increase the caloric content of the rations via additional supplements that provide energy-dense foods in bar format that can be easily consumed at the convenience of the individual.February 201

Human acclimation and acclimatization to heat A compendium of research

Annotated bibliography on human acclimation and acclimatization to hea

Oral application of L-menthol in the heat: From pleasure to performance

When menthol is applied to the oral cavity it presents with a familiar refreshing sensation and cooling mint flavour. This may be deemed hedonic in some individuals, but may cause irritation in others. This variation in response is likely dependent upon trigeminal sensitivity toward cold stimuli, suggesting a need for a menthol solution that can be easily personalised. Menthol’s characteristics can also be enhanced by matching colour to qualitative outcomes; a factor which can easily be manipulated by practitioners working in athletic or occupational settings to potentially enhance intervention efficacy. This presentation will outline the efficacy of oral menthol application for improving time trial performance to date, either via swilling or via co-ingestion with other cooling strategies, with an emphasis upon how menthol can be applied in ecologically valid scenarios. Situations in which performance is not expected to be enhanced will also be discussed. An updated model by which menthol may prove hedonic, satiate thirst and affect ventilation will also be presented, with the potential performance implications of these findings discussed and modelled. Qualitative reflections from athletes that have implemented menthol mouth swilling in competition, training and maximal exercise will also be included

Human acclimation and acclimatization to heat: A compendium of research, 1968-1978

Abstracts and annotations of the majority of scientific works that elucidate the mechanisms of short-term acclimation to heat in men and women are presented. The compendium includes material from 1968 through 1977. Subject and author indexes are provided and additional references of preliminary research findings or work of a peripheral nature are included in a bibliography

Space flight research relevant to health, physical education, and recreation: With particular reference to Skylab's life science experiments

Data collected in the Skylab program relating to physiological stresses is presented. Included are routine blood measures used in clinical medicine as research type endocrine analyses to investigate the metabolic/endocrine responses to weightlessness. The daily routine of physical exercise, coupled with appropriate dietary intake, sleep, work, and recreation periods were considered essential in maintaining the crew's health and well being

High Energy Foods: Review with Food Technological Perspective

Energy foods have gained a special interest all around the globe due to enhanced consumer awareness about activity-based calorie requirements. Energy-specific foods can be prepared in the form of bars/ fluids by using a combination of various types of ingredients such as cereals, pulses, nuts, and seeds. Energy foods provide concentrated calories specifically required for athletes and military personnel, those involved in high-endurance physical activities. The latter group was deployed in challenging terrains associated with harsh climatic conditions (high altitudes, hot and cold environments). In addition to the harsh climate, the situation worsens with limited accessibility and availability of regular food. Therefore, food and fluid intake will be considerably less, which ultimately disturbs the energy metabolism and health of an individual. The research poses challenges in the development of energy foods for specialised requirements and incorporating the highest energy in the lowest volume of foods. This is because of raw material selections, economics, product palatability and stability (shelf life) in adverse conditions. The high energy content, volume, and stability are suitable factors for using certain products as survival or emergency rations. Indeed, there was a necessity to understand the fate of energy metabolism and its medical implications in different harsh climatic conditions. The present review is a brief discussion about the influence of a challenging environment on nutritional and energy requirements and the significance of different energy foods