The amount of energy you expend during the day may not be associated with the amount of sleep we get, according to a study at the Walter Reed army Medical Centre which monitored 14 individuals wearing arm bands to measure body temperature, ambient temperature body position, motion, sleep efficiency and sleep time. It was revealed that subjects experiencing increased physical activity during the day had a lower sleep time each night and that a lower total sleep time was followed by increased activity the next day. The results suggest that even though exercise is good for one’s body and health, properly timing exercise ( eg.; not exercising right before bed time) is necessary to maximize it’s beneficial effects.
J Sleep and Sleep Disorders Research 2009: vol 32