Thursday, September 1, 2011
Weighing the Pros and Cons of Napping (For YOU, not your baby!) Part I.
Benefits of Napping
Even for parents who generally get the sleep they need on a nightly basis, napping may lead to considerable benefits in terms of mood, alertness, and thinking. Studies have documented the benefits of naps for night shift workers including improved mood and decreased feelings of sleepiness and fatigue. Naps also improve reaction time and logical reasoning. However, not all naps are created equal; there are several factors that affect how beneficial naps are. (Milner 2009)
Factors that Affect Nap Benefits
A number of factors may influence how valuable a daytime nap will be and how restored you will feel afterwards, including how well you slept the previous night, duration and timing of your nap, and the presence (or absence) of “sleep inertia” (defined below). Other factors such as your age, gender, how often you nap, and degree of sleepiness may also influence the benefits of napping. (Milner 2009)
Timing of the Nap
During the afternoon, between about 3:00 and 5:00 pm, there is a natural circadian dip in alertness. When you nap during this time, you fall asleep faster and have less “sleep inertia” (the confusion and grogginess you might have when you wake up from a long nap) compared to naps taken in the later evening (7:00 to 9:00 pm). (Milner 2009) When Milner compared 3 similar studies, where participants took a 20-minute nap once per week at either 12:20 pm or 2:00 pm, feelings of sleepiness and self-rated performance were improved after both nap times. However, scores on objective tests were only improved following the later nap. For those who are well-rested, a later nap (following more awake time) may provide the most benefits.
Nap Duration and Sleep Deprivation
For people who are sleep deprived, it’s important to nap long enough to experience deep sleep to reduce sleepiness and improve performance. Even 30-minute naps in sleep deprived individuals contain deep sleep and improve performance. However, after a night of sleep deprivation, a 15-minute morning nap had little effect on alertness and very small amounts of deep sleep, while a 60-minute nap resulted in the highest alertness gains. (Lumley et al., 1986)
Regular Naps vs. Occasional Naps
For people who take naps only occasionally, there are several drawbacks that may prevent napping on a regular basis. Non-habitual nappers may have a more difficult time falling asleep, awaken too often, or sleep lightly; they may also sleep too deeply, experiencing greater sleep inertia after the nap than regular nappers would.
Next time: In Part 2, we'll provide some tips to help you get the most out of your napping!