Ever wake up feeling that you’re not waking up? That parts of your brain do not want to and cannot rise from slumber, that alertness is far away?
Welcome to the problem of sleep inertia.
Sleep inertia can and often occurs when people wake up not feeling fully rested. In theory, if we’re sleeping well, sleep inertia should be brief. Generally people wake up from REM sleep, where the transition to wakefulness is usually not so difficult.
However, Americans are so sleep deprived that creating noisy, irritating alarm clocks is a growing industry. Generally we’re taking 20 minutes to 2 hours to get sort of fully alert – if psychomotor tests can be believed.
And then there’s the sleep inertia produced by naps.
When people nap, especially folks who are not shift workers napping in the normal biological nap times of early to mid afternoon, they move into stage 1 sleep. Stage 1 sleep truly is light sleep. Waking from stage 1 sleep usually produces no sleep inertia.
Stage 2 sleep, the majority of normal night-time sleep, is a different story. Some wake up out of stage 2 sleep quickly and readily, but quite a few feel groggy a long time. That’s why so many sleep clinicians suggest short naps of 10-20 minutes. You can nap, feel refreshed, and get back quickly to whatever you’re doing.
Many nap researchers, however, have a different response – and context.
Lots of nap researchers do their studies with students. College and graduate students have far more flexible schedules than many working people, especially when they do not have families. They are also massively sleep deprived, particularly as their bodies require about 9 -9.5 hours of sleep to perform well and many of them get far less.
They make great nap test subjects. And lots are used to long naps, particularly on weekends.
So data from nap researchers often demonstrate that 2 hour naps work well at refreshing people and having them wake feeling moderately alert. And if you cycle through the various different cycles of sleep, which usually takes around 90 minutes, you may come out on the other end in relatively light sleep, so sleep inertia won’t be much of a problem.
But watch out if you wake up from a nap in deep sleep. Deep sleep is deep. It can take quite a while to wake someone from deep sleep, and some may feel really draggy for a half hour to hours later.
Plus routinely getting long naps really tends to mess up night-time sleep and its normal circadian patterns – unless you’re a shift worker, in which case long afternoon naps prior to a night shift can be very useful.
Bottom line – to avoid sleep inertia, get short naps. It’s a particularly important point if you are getting naps on the job and must quickly return to a state of mental sharpness.
Body Clocks – Lark or Owl?
Time rules life. Body clocks schedule your life.
For more detail, please look at my book “The Body Clock Advantage.” But to simplify things enormously, it’s best to recognize that night is for sleep, and that most people nap most effectively in the early to mid afternoon.
Larks, or morning people, usually want to nap in the early afternoon. Owls, or true night people, who think 2 AM a sensible sleep time, will generally nap in the late afternoon.
The reasons we nap in the afternoon are complicated, but appear to at least follow body temperature markers. When body core temperature is going up, we get alert; when it’s going down, we get sleepy.
And in the afternoon that temperature curve gets pretty flat.
Flat body core temperature curves tend to be times when people like to nap – and that’s what is normally seen in the afternoon. Prior to artificial lights, diary studies suggest most of the population routinely took afternoon naps.
Short “power naps” can be remarkably useful, increasing work productivity as well as mood. However, for those unable to nap on the job, alternatives include active rest techniques, including my “UnNap Nap” described in “The Power of Rest.” The UnNap Nap won’t give you the true experience of sleep but can provide a restful state of relaxed concentration that can get you back to work refreshed. You also won’t have to fear that your boss will fire you for sleeping on the job.
Humans can and do sleep just about anywhere. Basic elements to help people nap include:
1. Lack of light – which can be gained by waring eye masks or, in a pinch, a rolled up hand towel over the eyes.
2. A comfortable place to lie on of at least 6 by 3 feet – futons, rugs, and couches can all work.
3. Relative quiet – some use noise cancellation headphones for this purpose (they’re not just for airplanes)
4. Relative coolness – hot environments make for poor sleep
5. A room that is in some way isolated from other spaces – at work conference rooms can be used, or a personal office with a closable door.
Getting the Perfect Nap
Obtaining the perfect nap is not always easy, but a fruitful, pleasant, productive is generally within reach. Most of the American population is sleep deprived, so naps have many useful functions, including:
1. Improving alertness
2. Improving productivity
3. Improving mood
4. Having us recognize that rest is regeneration, and can and should be obtained throughout the 24 hour day.
Rest, sleep, Sarasota Sleep Doctor, well-being, regeneration, longevity, body clocks, insomnia, sleep disorders, the rest doctor, matthew edlund, the power of rest, the body clock, psychology today, huffington post, redbook, longboat key news