Monday, January 26, 2009

The only true wisdom is in knowing you know nothing


How to Get the Nap You Need

Sara Mednick, PhD

University of California, San Diego

What if there were a safe, nontoxic, simple, free way to increase your alertness... boost your creativity... improve your memory... reduce your stress... and even reduce your risk for heart disease, all in just 20 minutes a day? There is. It's called a nap.

In our work-driven, activity-driven society, the hardest part of taking a nap is getting past that little voice in your head telling you that napping is a sign of laziness.

Reality: People who nap tend to be more productive, not less.

When you allow yourself that brief period of rest and refreshment, you wake up alert and energized, ready to be active for the rest of the day. The time you spend sleeping is more than made up for by the improved work or activity time a nap can give you.

Instead of a nap, you could just have coffee or another form of caffeine to perk yourself up, but a nap is a better idea. Caffeine makes you more alert, but it doesn't give you any of the other benefits of napping.

Example: Napping enhances performance on a wide range of memory tests. Studies show that a 90-minute nap is as good as a full night's sleep for improving memory.

To understand why napping can be so valuable, it helps to understand the basic concept of the sleep cycle and how it applies to both nighttime sleeping and daytime napping.

Through the night, your sleep moves through a consistent pattern of four distinct phases...

Stage 1. This occurs when you're just falling asleep and generally lasts for only a few minutes. Your structured thinking gradually gives way to dreamlike imagery.

Stage 2. After you've fallen asleep, stage 2 sleep takes over. During this time, many parts of your brain are less active, but stage 2 sleep is the sleep that restores alertness and helps consolidate motor learning -- anything that involves muscle movements such as dancing or driving.

Stage 3. When you move into stage 3 sleep, your brain waves slow down, so much so that this stage is also called slow-wave sleep (SWS). In SWS, your body repairs itself because growth hormone is secreted during this phase, which helps with muscle fiber growth and repair as well as bone growth -- basically, the antidote to cortisol, a stress hormone -- and consolidates memory, such as new information you've just learned (a phone number, for example) so that you'll remember it.

Stage 4. During stage 4, you move into rapid eye movement (REM) sleep, or dreaming. REM sleep is when you consolidate more complex information and learning, such as a vocabulary list in a foreign language.

In the course of the night, you generally go through stage 1 sleep only once, just as you fall asleep. After that, you cycle through stage 2, stage 3 (SWS) and stage 4 (REM) sleep several times through the night. Each cycle takes about 90 minutes. Of that, about 60% is spent in stage 2 sleep. The amount of time spent in SWS and REM sleep varies through the cycles.

Most people feel a natural lull in their energy levels sometime during the afternoon. That's the natural time for napping -- and in many countries, the traditional siesta happens then. Ideally, because one sleep cycle takes about 90 minutes, you would nap for that long and awaken feeling refreshed and alert.

Not too many of us can manage a full 90 minutes in the middle of the day, however, and not everyone feels the need to nap that long. To choose the best nap length for you, decide what you want to get from your nap...

Stage 2 nap. Reduces sleepiness, heightens alertness, increases concentration, enhances motor performance and elevates mood.
Sleep for: 15 to 20 minutes.

Stage 3 (SWS) nap. Clears away useless information, improves conscious memory recall and restores and repairs tissues.
Sleep for: 60 minutes.

Stage 4 (REM sleep) nap. Increases creativity, improves perceptual and sensory processing, and improves memory for complex information.
Sleep for: 90 minutes.

The best time for your nap depends on several factors, including when you woke up and what type of sleep you want to get from your nap. I've created a handy Nap Wheel to help you determine when the ideal time for your nap is.

We know that lack of sleep is definitely bad for your health, but is napping good for it? That has actually been a hotly debated question. Over the years, some studies seemed to show that people who often napped had a greater risk for death, especially from heart disease.

A recent Harvard University study, however, strongly suggests the opposite. In the study, more than 23,000 people in Greece were followed for an average of 6.3 years. None of the individuals had a history of heart disease, stroke or cancer at the start of the study, and they ranged in age from 20 to 86. The results showed that the people who regularly napped for at least 30 minutes at least three times a week had a 37% lower risk for death from heart disease than the non-nappers.

Taking a nap in the afternoon doesn't usually affect a person's ability to get to sleep at his/her normal bedtime or to sleep for the normal number of hours at night. In fact, many people who start taking daytime naps report that they fall asleep more easily at bedtime and feel more refreshed in the morning.

Exception: Don't nap within two to three hours of your usual bedtime -- it could keep you from getting to sleep on schedule.

Older adults often find themselves waking up earlier than they used to and having trouble getting back to sleep. Shifting to an earlier wake-up time -- and feeling the need for an earlier bedtime -- is a natural part of the changes in body rhythm that come with aging. Rather than fighting your body's normal needs, accept them. A great way to make up for the lost sleep and help yourself stay up later? Take a nap!

The Nap Wheel is on the cover of my book Take A Nap! It’s also available on my Web site
Use the Nap Wheel to design your own custom nap based on the time you wake up in the morning.

Change will not come if we wait for some other person or some other time. We are the ones we've been waiting for. We are the change that we seek

Barack Obama

[QN: I need a nap]

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You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.

Harlan Ellison