This study aimed to test the primary hypotheses that human thermoregulatory behavior is: (1) initiated before changes in rectal or esophageal temperatures; and (2) accompanied by indiscernible differences in sweating or shivering. This was achieved by placing nine, healthy, males in a situation where they were free to move between a cold (~8 °C) and a hot (~46 °C) environment. Upon behaving [i.e., move from cold to hot (C→H) or from hot to cold (H→C)], skin, rectal, and esophageal temperatures, indices of cutaneous vasomotor tone, metabolism and evaporation, and local and whole-body thermal discomfort were recorded. Rectal temperatures were similar at H→C (37.1 ± 0.2 °C) and C→H (37.1 ± 0.2 °C); yet esophageal temperatures were higher at C→H (36.9 ± 0.2 vs. 36.8 ± 0.2 °C). Skin temperature (C→H, 28.4 ± 0.9 vs. H→C, 35.0 ± 0.6 °C) and vasomotor tone were drastically different upon the decision to behave. Metabolic heat production was lower at H→C (79 ± 10 W/m(2)) than at C→H (101 ± 20 W/m(2)), yet there were no statistical differences in evaporative heat loss (C→H, 23 ± 33 W/m(2) vs. H→C, 52 ± 36 W/m(2)). Whole-body thermal discomfort was similar at C→H and H→C, yet there were inter-segmental differences. These findings indicate that skin temperature, not core temperature, plays a signaling role in the decision to behaviorally thermoregulate. However, this behavior does not occur in the complete absence of autonomic thermoregulatory responses.

The purpose of this study was to assess the reliability of a 15-min time trial preloaded with 45 min of fixed-intensity cycling under laboratory conditions of thermal stress. Eight trained cyclists/triathletes (41 ± 10 years, VO2peak: 69 ± 8 mL/kg/min, peak aerobic power: 391 ± 72 W) completed three trials (the first a familiarization) where they cycled at ∼ 55% VO2peak for 45 min followed by a 15-min time trial (∼75% VO2peak) under conditions of significant thermal stress (WBGT: 26.7 ± 0.8°C, frontal convective airflow: 20 km/h). Seven days separated the trials, which were conducted at the same time of day following 24 h of exercise and dietary control. Reliability increased when a familiarization trial was performed, with the resulting coefficient of variation and intraclass correlation coefficient of the work completed during the 15-min time trial, 3.6% and 0.96, respectively. Therefore, these results demonstrate a high level of reliability for a 15-min cycling time trial following a 45-min preload when performed under laboratory conditions of significant thermal stress using trained cyclists/triathletes.Performance is one of the most common outcome measures within the exercise sciences and often used to assess the efficacy of treatment effects, such as training programs and a number of possible ergogenic aids (nutritional, pharmacological, physiological, etc.). When performance is measured, it is necessary to know the reliability of such a test, as lack of this knowledge might result in wrongfully concluding no difference because of high test variability or intra-/inter-subject variation. Therefore, knowledge of the typical variance associated with a performance test used on a certain sample under those (often laboratory) conditions allows for a more informed decision on the magnitude of a treatment effect. Another of the advantages of using laboratory protocols and equipment that display low variation (high reliability) is that "real" differences can be determined with realistically small sample sizes, especially when concurrent with lifestyle standardization (e.g., diet, exercise, time of day, etc.) and a within-subject design.Traditionally, submaximal exercise capacity tests using an ergometer have been used to cycle at a fixed percentage of maximal workload (W max )/O 2 uptake (VO 2max ) to volitional exhaustion (or a predetermined marker thereof). Such tests have largely been used to give basic/mechanistic data during a physiological steady state; however, their face validity is poor. Furthermore, such tests have usually yielded a high level of variability even when using trained participants. For example, Jeukendrup et al. (1996) observed a test-retest coefficient of variation (CV, a common measure reporting the within-subject variation expressed as a percentage of the mean) of ∼27% using trained cyclists/ triathletes when they cycled to exhaustion at 75% W max ; they argued that "open-ended" tests are influenced more heavily by psychological factors such as motivation and boredom. In contrast to these...

Introduction: Nutrition plays a vital role in sports. Athletes must understand the importance of diet and ensure that they meet the nutrient requirements to enhance sports performance. The lack of understanding in sports nutrition will lead to poor dietary practices that can cause detrimental effects on athletic achievements. This study aims to evaluate the effects of knowledge, attitude, and practice (KAP) regarding sports nutrition and dietary intake among young university athletes. Methods: Twenty-one local university athletes (23.8±3.4 years) were recruited, and their anthropometric and socio-demographic data were assessed. All participants attended a 1-day sports nutrition class. The KAP-Sports nutrition questionnaire was administered. Three days of dietary intake were also recorded at the same timepoints among the participants. Results: There was a significant increment (p<0.05) in the mean scores for KAP among the participants. Total energy and total carbohydrate intakes per day were significantly increased (p<0.05). However, overall protein and fat intakes did not improve as the readings were higher than the recommended values. Conclusion: In this study, sports nutrition education improved participants’ KAP, but not the actual dietary intake. Changes in habit require more effort, with extra attention on protein and fat intakes.

The present study determined whether 0.8g/kg bodyweight sago ingested before (Pre-Sago) or during (Dur-Sago) exercise under warm-humid conditions (30 ± 2°C, 78 ± 3 % RH; 20 km·h−1 frontal airflow) conferred a performance and/or physiological benefit compared to a control (Control) condition. Eight trained, male cyclists/triathletes (45 ± 4 y, VO2peak: 65 ± 10 ml·kg−1·min−1, peak aerobic power: 397 ± 71 W) completed 3 15-min time-trials (∼75% VO2peak) pre-loaded with 45 min of steady-state (∼55% VO2peak) cycling following > 24 h standardization of training and diet. Measures of work completed, rectal and mean skin temperatures, heart rate, expiratory gases and venous blood samples were taken. Compared to Control, Pre-Sago resulted in a smaller rise in rectal temperature (0.3 ± 0.5°C) while heart rate increased to a greater extent (6 ± 13 beats·min−1) during exercise (both P < 0.05), however, compared to Control time-trial performance remained unaffected (Pre-Sago: −0.5 ± 4.0%, P > 0.05). During exercise, plasma glucose concentrations were maintained higher for Dur-Sago than Control (P < 0.05), however substrate oxidation rates remained similar (P > 0.05). Dur-Sago also resulted in a higher plasma sodium concentration (2 ± 2 mmol·l1) and lower whole-body sweat loss (544 ± 636 g) and, therefore, reduced plasma volume contraction (all P < 0.05). Heart rate increased to a greater extent (5 ± 13 beats·min−1) during Dur-Sago, yet compared to Control time-trial performance remained unaffected (+0.9 ± 2.3%, P > 0.05). Uniquely, these results indicate that during exercise heat stress feeding sago can result in some ‘beneficial’ physiological responses, however these do not translate to changes in exercise performance when performed in a post-prandial state.

This study determined whether sago porridge ingested immediately after exercise (Exercise 1) in warm-humid conditions (30 ± 1°C, 71 ± 4 % RH; 20 km·h−1 frontal airflow) conferred more rapid recovery, as measured by repeat performance (Exercise 2), compared to a control condition. Eight well-trained, male cyclists/triathletes (34 ± 9 y, VO2peak 70 ± 10 ml·kg−1·min−1, peak aerobic power 413 ± 75 W) completed two 15-min time-trials pre-loaded with 15-min warm-up cycling following >24h standardization of training and diet. Mean power output was not different between trials during Exercise 1 (286 ± 67 vs. 281 ± 59 W), however, was reduced during Exercise 2 for control (274 ± 61 W) but not sago (283 ± 60 W) that led to a significant performance decrement (vs. Exercise 1) of 3.9% for control and an improvement (vs. control) of 3.7% for sago during Exercise 2 (P < 0.05). Sago ingestion was also associated with higher blood glucose concentrations during recovery compared to control. These results indicate that feeding sago during recovery from exercise in a warm-humid environment improves recovery of performance during a subsequent exercise bout when compared to a water-only control. As these effects were larger than the test-retest coefficient of variation for work completed during the 15-min time-trial (2.3%) it can be confidently concluded that the observed effects are real.