Investigation of the effects of short-term body weight loss on endurance performance in combat sports athletes

The aim of this study was to investigate the effect of short-term body weight loss on endurance performance in combat sports athletes. Twelve experinced male combat sports previously lost weight for competitions were participated as volunteer in this study. Athletes are involved in a period with weight loss as experimental application and a period without weight loss as control application in a randomized crossover design with one week interval. Measurements were done before weight loss (BWL), during weight loss (DWL), after weight loss (AWL) and 18 hour after recovery period (ARP). Athletes were ensured to lose 5% of their body weight within 48 hours. In this period anthropometric characteristics and body composition, nutrition and fluid consumption, endurance performance, serum and urine biochemical samples and the hormones related to endurance performance were examined. Two way ANOVA with repeated measures were used for statistical analysis. According to the statistical analyses VO2max, ventilation, total running time and maximum heart rate were significantly (p<0,05) decreased due to weight loss. Moreover significant (p<0,05) reduction was found in body fat percentage, fat mass, fat free mass, total body water, circumference measurements (biceps, abdomen and mid-thigh) and in food and fluid consumption. However, significant (p<0,05) increase was seen in haemoglobin, serum osmolarity, serum sodium, chlorine and cortisol level, and in urine density, glucose and potassium level. On the other hand significant (p<0,05) decrease was shown in serum insulin, urine sodium and chlorine level. Consequently, the results of this study revealed that 5% body weight loss within 48 hours affect aerobic capacity, body composition and physiological responses related to endurance performance negatively. Therefore the respondents should avoid the combat sport athletes from performing rapid weight loss in order to protect their athletic performance and health.