The effect of sleep loss on high intensity exercise and recovery.

The cardiovascular and metabolic responses of five male subjects during submaximal exercise (80% Vo2 max) were examined after 24 h of wakefulness. The protocol consisted of two sets of two trials separated by 7-10 days: first, a 20 min exercise bout, then a normal night's sleep, followed by another 20 minutes of exercise; second, a 20-min exercise bout, 24 h of wakefulness, then another 20 min exercise trial. Exercise ventilation, heart rate, and oxygen uptake were not affected by sleep loss. However, sleep loss caused the recovery ventilation and oxygen uptake to remain higher than normal during the slow phase of recovery. Blood glucose levels were found to be greater during the sleep deprived trials compared to controls, but were similar to controls 15 min after exercise. Blood lactates were lower at the end of exercise after sleep deprivation and remained lower during the recovery period. Changes in plasma volume were not affected by sleep loss. These results suggest that although sleep loss may not overtly affect acute submaximal exercise performance, it attenuates the recovery process.