Afternoon Nap, The Benefits

Many people feel a mid-afternoon slump in mood and alertness, especially after a poor night of sleep. Many believe that this slump is caused by eating a heavy lunch. However, in reality, this occurs because we were meant to have a mid-afternoon nap.

A mid-day nap is an integral part of the daily routine of many cultures, particularly those near the equator. This suggests that napping may have been part of an evolutionary mechanism to get us out of the hot midday sun. However, because the urge for a nap is appreciably weaker than the need to sleep at night, it can be suppressed (or masked by caffeine) but at the cost of increased sleepiness and reduced mood and performance.

Research on napping suggests that an afternoon nap as short as ten minutes can enhance alertness, mood, and mental performance, especially after a night of poor sleep. Several studies also suggest that polyphasic sleep in the form of 30 minute naps taken regularly (every 4 hours) is the only way to reduce nocturnal sleep below 5-6 hours and still maintain performance.

Why do afternoon naps affect cardiovascular function? One reason could be changes in blood pressure. At night, our blood pressure and heart rate decreases as we sleep. Some researchers hypothesize that the lower blood pressure reduces strain on the heart and decreases the risk of a fatal heart attack.

Most studies have focused on cardiovascular behavior in nighttime sleeping. This study provides a detailed description of changes in cardiovascular function of daytime sleep in healthy individuals, comparing napping with other daytime activities such as standing and lying down without going to sleep.