Effects of sleep deprivation on endurance performance and hormonal responses to endurance exercise

Sleep deprivation affects physiological and psychological functioning and probably increases the body's energy demand. It seems that sleep deprivation can have a negative effect on athlete's performance and affect the body's hormones secretion. This study investigated the effect of 24-hour sleep deprivation on endurance performance and hormonal responses to endurance exercise. Twenty young men with a history of resistance training were divided into experimental and control groups (double blind and randomly). In two separate days, once after a normal circadian sleep and again after 24 hours of sleep deprivation, endurance performance of subjects was assessed using the Bruce test. Immediately after the Bruce test, blood samples were collected and level of cortisol and testosterone with chemiluminescence method and level of epinephrine and norepinephrine with ELISA method were measured. In order to analyze data, the dependent and independent t-tests were used respectively to examine within groups and between groups changes of variables. The maximal oxygen consumption significantly decreased and cortisol level increased in the experimental group. Post-test cortisol level in experimental group was significantly higher than control group, but regarding other variables, there were not a significant difference between the two groups. Our study indicated that 24-hour sleep deprivation can have negative effects on endurance performance and increases cortisol response to endurance exercise, but it does not change testosterone, epinephrine and norepinephrine response to endurance exercise.