15 December 2008

Lose weight while you sleep. Sounds weird huh?! Sleep means not doing anything, no activity and no burning calorie. How could that be posibble?

Well, researchers say that how much you sleep and quite possibility the quality of your sleep may silently orchestrate a symphony of hormonal activity tied to your appetite.

Sleep and sleep disruption do remarkable things to the body including possibly influencing our weight.

Have you ever heard about Leptin and ghrelin hormone? Both of them can influence our appetite. And studies show that production of both may be influenced by how much or how little we sleep.

How Hormones Affect Your Sleep
Leptin and ghrelin work in a kind of "checks and balances" system to control feelings of hunger and fullness.

Ghrelin produced in the gastrointestinal tract, stimulates appetite.
Leptin produced in fat cells, sends a signal to the brain when you are full.

When you don't get enough sleep, it drives leptin levels down, which means you don't feel as satisfied after you eat. Lack of sleep also causes ghrelin levels to rise, which means your appetite is stimulated, so you want more food. The two combined, he says, can set the stage for overeating, which in turn may lead to weight gain.

Those Who Sleep Less Often Weigh More
In the Chicago study, doctors measured levels of leptin and ghrelin in 12 healthy men. They also noted their hunger and appetite levels. Soon after, the men were subjected to two days of sleep deprivation followed by two days of extended sleep. During this time doctors continued to monitor hormone levels, appetite, and activity.

When sleep was restricted, leptin levels went down and ghrelin levels went up. Not surprisingly, the men's appetite also increased proportionally. Their desire for high carbohydrate, calorie-dense foods increased by a whopping 45%. Those who slept less than eight hours a night not only had lower levels of leptin and higher levels of ghrelin, but they also had a higher level of body fat. What's more, that level of body fat seemed to correlate with their sleep patterns. Specifically, those who slept the fewest hours per night weighed the most.

Eating and Sleep Apnea
People with sleep apnea may stop breathing for up to a minute, sometimes hundreds of times during the night while sleeping. Physical abnormalities inside the mouth and neck cause the soft tissue in the rear of the throat to collapse. This briefly closes off air passages many times during a night, causing disruption in breathing and a tendency to snore.

Although you may go to bed early and think you are getting a good night's rest, the disruption in breathing prevents you from getting deep sleep. Eight hours of disrupted shut eye can leave you feeling like you had only four.

Patients who suffer from sleep apnea are more likely to be obese. However, studies show they do not have the usual low leptin levels associated with being overweight. Folks with sleep apnea have uncharacteristically high levels of leptin. What's more, when their apnea is treated, leptin levels drop and somehow that helps them to lose weight.

So why does low leptin seem to cause weight gain in some folks while allowing others to lose weight? One theory says that it may not be the level of this hormone that matters so much as a person's individual response to it. In much the same way that obese people can become resistant to insulin, folks with apnea may be resistant to the fullness signal that leptin sends to the brain.

So, if now you are dieting, logging in a few extra hours of sleep a week is not a bad idea, particularly if you get six hours of sleep or less a night. You may just discover that you aren't as hungry, or that you have lessened your craving for sugary, calorie-dense foods.


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