ROLE OF SWEAT AND SODIUM LOSS ON RUNNING PERFORMANCE IN OVERWEIGHT INDIVIDUALS

บทคัดย่อ

Half - marathon is considered a physiological stress to the thermoregulatory system because excess of heat generated. Due to the insulation property of fat, runners with high body fat would have poor thermoregulation. Thus, overweight individuals may experience diminished loss of sweat and poor physical performance. However, no study thus far has examined the effect of body fat on sweat and sodium loss during half - marathon. Therefore, the objective of this study was to assess running performance as well as rate of sweat and sodium loss in overweight individuals during half - marathon. Nine healthy male runners (CR; %body fat < 26.1) and nine overweight male runners (OR; %body fat ≥ 26.1) participated in this study. The subjects were asked to perform two running trials. The first one was a 10 - km running during which the rate of sweat loss was determined. In the second trial, each subject underwent a self - pace half - marathon when the sweat rate and total running duration were recorded. We found that a higher (64%) of sodium loss was observed in the OR. However, %bodyweight loss in the OR was 17.5% less than that of the CR (p < 0.05). In addition, rate of sodium loss was positively correlated with percent body fat (p < 0.05, r = 0.478). In spite of these findings, the duration to complete half - marathon running was not significantly different between the CR and OR. Collectively, our observation indicated that the rate of sweat and sodium loss has little to no effect on running performance in overweight individuals.