Want to Lose Weight? Get Enough Sleep

There is a good reason we spend one-third of our lives sleeping. Our body is like a battery whose energy is drained during the day and needs recharging at night. Sleep is as vital and necessary to our survival as air, food and water.

If you have ever stayed awake all night cramming during final exam week or have had to deal with a newborn baby, you know the classic symptoms of sleep deprivation – fatigue, drowsiness, an inability to concentrate, moodiness and a feeling like you have cotton inside your head instead of a brain.

What you may not realize is that lack of sleep can also make you gain weight.

Hormones affected by lack of sleep
Scientists are still not exactly sure why lack of sleep can cause weight gain, but they are focusing their investigation on three hormones – leptin, cortisol and growth hormone.

Leptin has been called the "satiety hormone" because it tells you to stop eating when you are full. Low levels can make you eat more food than you need since you don't feel satisfied.

Cortisol is a stress hormone that increases your appetite and directs fat to be stored in the abdomen.

Growth hormone isn't just to make children grow. In adults, it repairs muscles and regulates muscle-to-fat ratio. This is the stuff that helps make your muscles – depending on the kind of workout you are doing – stronger, harder, firmer and bigger.

While you were sleeping ...
You might think nothing happens while you are asleep. But actually your body and brain are busy doing repair and maintenance work. Sleep comes in five stages which last for about 90 minutes and is repeated in four to five cycles a night. The first four stages are non-REM sleep and the fifth stage is REM sleep.

REM or rapid eye movement sleep is when you dream. Your eyes move rapidly back and forth while you have visual dreams. Your muscles are paralyzed though they may twitch, and your blood pressure, heart rate and breathing are erratic.

The brain is very active. Scientists believe this is a time of mental renewal when your mind reorganizes itself, throwing out unnecessary pieces of information and re-filing what is left to make sense the next day.

Non-REM sleep is when you are physically restored. Stage one is a state of drowsiness. Stage two is light sleep while stages three and four are deep sleep. These last two stages are also called slow-wave sleep because your brain waves are at their slowest.

During deep sleep, your body repairs tissues, including the skin. Since older people spend only five percent of the night in deep sleep, this may partly explain why the skin ages. Growth hormone production reaches its peak during deep sleep, specifically between midnight and 2 AM.

A 1999 University of Chicago study that was published in "The Lancet" found that lean young men who slept four hours a day for 16 days had decreased levels of leptin and increased levels of cortisol.

These hormonal changes made them so hungry that they consumed 1,000 extra calories a day. Not only that.

Head researcher Eve Van Cauter discovered that their insulin and blood sugar levels resembled those of pre-diabetics, a condition called "impaired glucose tolerance." This means that their sleep-deprived bodies were not processing carbohydrates properly.

The participants' blood chemistry returned to normal after the experiment, when they resumed their regular sleeping patterns. But in people who are chronically sleep-deprived, this pre-diabetic state could trigger Type-2 diabetes and obesity later on in life.

Deep sleep and the middle-age bulge
Van Cauter did another study that was published in the 2000 Journal of the American Medical Association. This time she focused on middle-aged men.

Typically, men get less deep sleep as they get older. Women get more deep sleep than men until after menopause when their sleep patterns become similar.

Two-thirds of a man's growth hormone production occurs during deep sleep, while for women it's only one-third.

Growth hormone production reaches its peak during deep sleep so less time spent in deep sleep means less growth hormone. The result? A harder time losing weight, more fat in the abdominal area, and less muscle mass and strength.

More bad news. Van Cauter's study found that although young and middle-aged men sleep the same number of hours, they are not getting the same amount of deep sleep.

Men who are 25 years old and below get 20 percent deep sleep while those between 25 and 35 years get 12 percent. After age 35, it's 5 percent or less.

Van Cauter found that because of the decline in deep sleep, a 45-year-old man's growth hormone production has dropped by 75 percent. Previously, scientists thought this only occurred when men reached the age of 60. This may explain why even very fit middle-aged men complain that they have stubborn love-handles they can't get rid of.

Even more bad news. As we age, we spend less time in REM or dream sleep. This is associated with an increase of cortisol during the nighttime.

Cortisol is also known as the alertness hormone. It is highest in the morning when we need to be awake and alert. Its levels drop as the day goes on and should be lowest in the evening, giving the body time to recover from its stimulating effect.

Constantly high cortisol levels can cause more fat to be deposited in the abdominal area, which in turn increases the risk of getting heart disease and Type-2 diabetes.

The quality of your sleep is just as important as the quantity when it comes to waking up refreshed as well as maintaining your weight.

You can get the correct number of hours of sleep but if you are awakened several times because of sleep apnea (difficulty in breathing during sleep) or the loud snores of your bed partner, you may not get enough of the deep sleep or REM sleep that you need. This, in turn, will affect your growth hormone and cortisol levels.

Practical implications
After all this bad news, you might be thinking, "What's the use? The odds are stacked against me. I'll just be old and fat." Not true. By watching your diet and exercising regularly, you can keep the middle-age bulge down to a minimum. Just don't compare your body with that of a 20-year-old or you will get very frustrated.

This research shows how important it is to make sure you get enough sleep. It's bad enough that there are age-related changes in our sleep that are beyond our control. Let's not make matter worse by not getting enough of it.

Scientists like Van Cauter are also experimenting with medication to lengthen deep sleep and dream time to delay the effects of aging.

No energy to exercise
Still another reason why lack of sleep can make you gain weight is you have no energy to exercise. This is a no-brainer. How can you feel like exercising when you can barely stay awake during the day because you aren't getting enough sleep at night?

How can you tell if you are getting enough sleep? Constantly sleeping one or two hours less a day leads to a condition that sleep researchers call "chronic sleep debt."

Many people are so used to living this way that they think this is normal. They don't realize how much better they can feel and function if they sleep the required number of hours appropriate for them.

According to the US National Sleep Foundation, newborns need 16 hours, toddlers need 11 hours plus a two-hour nap during the day, pre-schoolers need 11 to 12 hours, school-age children need 10 hours, teens need about nine hours, and adults need an average of eight hours.

Elderly people usually sleep six hours but it is not sure whether this is a normal sign of aging or something that can be prevented.

Some people need a little less than eight hours, while some need a little more. Some really unusual people are genetically predisposed to do very well on just four or five hours.

How can you tell how much you need? Sleep experts say you are getting enough if you can wake up without an alarm clock, you aren't sleepy during the day, and you have no difficulty falling asleep at night.

Epworth Sleepiness Scale
Another way to find out if you are getting enough sleep is the Epworth Sleepiness Scale. Based on the following situations and the way you have been feeling in recent times, how likely are you to doze off or fall asleep? If you have not encountered some of the situations recently, imagine how you would react if you did.

Use the following scale to choose the most appropriate number for each situation: 0=would never doze, 1=slight chance of dozing, 2=moderate chance of dozing, 3=high chance of dozing.

"Chance of dozing" situations: Sitting and reading, watching TV, sitting inactive in a public place (example, a theater or a meeting), as a passenger in a car for an hour without a break, lying down to rest in the afternoon, sitting and talking to someone, sitting quietly after lunch without alcohol, in a car while stopped for a few minutes in traffic.

Interpret your score: 1 to 6=you are getting enough sleep; 7 to 8= your score is average; 9+=you are abnormally sleepy.

Next week: How to get a good night's sleep.

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