Tag: sleep

I finished my high school in Dar-es-salaam, Tanzania. It was in a boarding school. We had no high school where I was born, Musoma, a port on Lake Victoria. The climate in Musoma is little milder than the scorching, coastal, humid heat of Dar-es-salaam. Our classes would end at 2:00 p.m. and before starting our homework, we had to return to our dorms and take a siesta for an hour.

Few years ago, we were in Spain travelling by train. If we reached our destination after lunch then we could not find any food till the evening. Almost everything shuts down in the afternoon for a siesta. Then evenings are spent drinking wine and eating delicious tapas. That is at the very heart of their lifestyle and culture. They know how to live.

Taking “power naps” during internship, residency and then working as a surgeon became a habit for me. Now it is impossible to go without taking a nap. Depending on the circumstances, the naps can be anywhere from five minutes to 20 minutes long. It is very refreshing.

When it comes to taking naps, I am sure, many of you have had the same kind of experience as I have had, Men are well known for dosing off on the sofa after a meal while the TV is on. I use my naps as part of my meditation time. I start with slow deep breathing exercises and then slide into a snoring session. My alarm wakes me up and then I am ready and fresh to begin work.

Sometime ago, I read an article in the New York Times (NYT) titled “A Look at Who Naps” (July 29, 2009). It says one in three adults admit that on any typical day they take a nap. A survey taken in the U.S. revealed all kinds of individuals take naps.

If you are sleep deprived due to some reason of health, work or travel then, you will take a nap. Even the stoic ones, who feel they can sleep for four to five hours a night and carry on realise that they need to do some sleep catch-up time.

Americans average 6.9 hours of sleep on weeknights, according to the National Sleep Foundation. Ideally, a healthy adult should sleep seven to eight hours a night. If you are sleep deprived then you are not thinking as clearly as you would like to. If your are sleep-deprived for 24 hours straight, then you are cognitive equivalent of being legally drunk. Your performance suffers.

Studies have shown that the sleep-deprived among us are lousy judges of our own sleep needs. We are not nearly as sharp as we think we are, says the NYT article.

There is stigma attached to napping. Your associates, friends or family may think you are lazy or lack ambition. Of course that is not true. If that was the case then I wouldn’t be writing about it.

Confessed nappers include Albert Einstein, Winston Churchill, Thomas Edison and Presidents Ronald Reagan and Bill Clinton.

According to one sleep expert quoted in the NYT article, napping should have the status of daily exercise. Nobody has defined what constitutes a nap. The National Sleep Foundation points out on its Web site: “While naps do not necessarily make up for inadequate or poor quality night time sleep, a short nap of 20-30 minutes can help to improve mood, alertness and performance.”

And that is good for your health.

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We have a 24-hour biological clock (circadian rhythm) that synchronizes a person’s sleep schedule with the changing amounts of light (day/night).

A tiny area of the brain, the suprachiasmatic nucleus (SCN), interprets light signals sent from the eyes through the optic nerves. The light triggers SCN to direct the brain’s pineal gland to release the hormone melatonin. There’s a big burst of melatonin into the body just as we go to sleep. Sleep researchers postulate that melatonin probably turns certain areas of the brain off and on as we transition into sleep mode.

Adenosine is another chemical thought to induce sleep. Adenosine levels increase during the day, making us sleepier the longer that we’re awake in an attempt to reach homeostasis (the body’s “steady state”). Once we fall asleep, adenosine levels drop, reducing the need for sleep and eventually prompting us to wake up.

Cortisol, known as a stress hormone, follows a different path. The blood levels of cortisol go down right before bedtime, allowing us to relax, but then increases throughout the night to encourage a fresh energetic start to the day.

While we are asleep, our body is working very hard to repair the internal damage done during the day.

Sleep helps heal tissues and restore them to its original form. Sleep is important for our immune system. Sleep deprivation impairs our ability to combat infection and stay healthy. It has been postulated that sleep effectively combat the accumulation of free radicals in the brain, by increasing the efficiency of our body’s antioxidant mechanisms.

Free radicals are atoms or groups of atoms with an odd (unpaired) number of electrons and can be formed when oxygen interacts with certain molecules. Free radicals have a capacity to cause cell damage (DNA), Cell damage can lead to cancer, aging, and a variety of diseases.
Antioxidants help us to prevent cell damage (DNA).

Although there are several enzyme systems within the body that scavenge free radicals, the micronutrient (vitamin) antioxidants are vitamin E, beta-carotene and vitamin C. The body cannot manufacture these micronutrients so they must be supplied in the diet (fruits and vegetables and pills).

Although it has not been proven, sleep helps with body growth by having some influence on the growth hormone. Studies investigating the effects of deprivation of active sleep have shown that deprivation early in life can result in behavioral problems, permanent sleep disruption and decreased brain mass.

Scientists have shown numerous ways in which sleep is related to memory. In one test, the average working memory span of the sleep-deprived group had dropped by 38 per cent in comparison to the control group.

Sleep researchers continue to work on the importance of sleep to keep us healthy and smart. So far the evidence shows that sleep does not harm us. In fact, without enough sleep we can look forward to lots of health problems in life. So, listen to your doctor and to your mother. Sleep well. Have sweet dreams. Wake up in the morning like a million dollar person and say, “Thanks, mom!”

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Going to bed and falling asleep is a gradual progression of stages in which body and brain activity changes. Scientists have been studying this for many years. Besides brain activity, sleep researchers study eye movements and muscle tension to observe a person falling asleep.

During sleep there is reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. Our body goes into anabolic state when tissues found within the human body obtain energy for growth and maintenance of our immune and other systems. Anabolism requires energy to occur. Sleep is often thought to help conserve energy, but actually decreases metabolism by only about five to ten percent.

The purposes and mechanisms of sleep are only partially clear and are the subject of intense research. But here is what we know:

1. A night’s sleep has a typical pattern. It is broadly divided into two categories: Non-Rapid Eye Movement or NREM sleep which has four stages (N1 to N4) and Rapid Eye Movement or REM sleep.

2. Sleep proceeds in cycles of NREM and REM, the order normally being N1 → N2 → N3/4 → N2 → REM.

3. Each sleep cycle lasts from 90 to 110 minutes on average. Each stage may have a distinct physiological function. During an eight-hour-sleep, we go through NREM to REM cycle four to six times.

Are you confused? You are not alone. Stay awake and I will tell you more.

First, we undergo NREM sleep, which takes up 75 per cent of sleep time.

Stage 1 finds us dozing off, with our brain waves and muscle activity slowing down. This is light sleep. When woken during Stage 1 and asked if they were asleep, about 80 percent of people will say they were not.

Stage 2, this is an actual moment when you are asleep. Usually comprising about half of sleep time. There are calmer brain wave pattern and no eye movements. Breathing slows and body temperature drops slightly. A person loses touch with his surroundings but can easily be shaken awake.

By Stages 3 and 4, a person is in deep sleep and takes a bit to be woken. Breathing slows even more into a rhythm. Blood pressure and body temperature drop and muscles relax. These two similar stages are called “slow wave sleep,” with the slowest of all brain waves. Much of the body’s regenerative work, like protein building and hormone release, happens at this stage.

Then comes REM sleep. which is dream-heavy period. About 90 minutes after falling asleep, REM sets in. This is the slow wave sleep that is very close to being awake, with brain waves of the same speed or even faster. Most but not all dreams occur in this phase.

There is rapid heart bit, blood pressure rises, eyes move around and breathing becomes rapid and shallow. The body is more or less paralyzed; arm, leg and facial muscles might twitch, but the body won’t move. REM can last from five to 30 minutes.

After REM, NREM starts again. Almost every two hours we go through the whole cycle. As the night progresses, the time spent in REM increases and deep sleep decreases so that when your morning alarm goes off, it’s almost all Stage 1, Stage 2 and REM sleep.

Enough for today? There is a lot to absorb and sleep over. More about sleep next week.

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