What effect does a decrease in body temperature have on the sleep-wake cycle?

A decrease in body temperature plays a significant role in promoting sleepiness as part of the body's natural sleep-wake cycle. During the transition from wakefulness to sleep, the body typically experiences a drop in core temperature. This decline in temperature helps to facilitate the onset of sleep by signaling to the body's internal clock that it is time to rest.

Lower body temperature is associated with the decrease in metabolic activity and the release of sleep-promoting hormones like melatonin. These physiological changes collectively enhance feelings of drowsiness and prepare the body for the sleep stages that are crucial for restorative processes.

The other options do not accurately reflect the effects of decreased body temperature in the context of the sleep-wake cycle. Promoting alertness and stimulating wakefulness are connected to increases in body temperature and metabolic activity, which counteract the feelings of sleepiness. Likewise, increasing metabolism is generally associated with an increase in body temperature and energy expenditure, which is contrary to the body's need for rest during sleep.