Can sleeping more help you lose weight?
At first, the idea seems counterintuitive. But research shows
that sleep deprivation can cause hormonal and metabolic
changes that can lead to weight gain. Plus, when you're
feeling sluggish you're more likely to crave empty calories
like chips or cookies, and less likely to have the energy to
Let us discuss the complex relationship between sleep and
body weight. How can sleeping too little, affect body
When we sleep too little, we produce more cortisol, the
stress hormone in the body. Cortisol in turn, causes the
release of insulin and higher insulin levels are associated
with increased weight because insulin is a hormone that
promotes fat storage.
Another factor associated with sleep restriction that might
lead to increase in weight is increased hunger. It seems as
if the body responds to sleep restriction by craving more
fuel. Leptin is a molecule secreted by fat cells and it
conveys a satiety signal that says, "There's enough fuel on
board." With sleep restriction, even when the level of
activity and the amount of calories are constant, the body
says, "I need more food." This is inappropriate and may lead
to overeating and potentially to obesity in the long term.
What other effects does sleep restriction have on the
From sleep restriction experiments it's clear that with just
a week of sleep loss, sleeping only four hours a night,
insulin levels are higher and the ability of blood sugar to
be used is dramatically altered. And these changes developed
in healthy young adults in just a week of sleep loss. The
alterations of blood sugar metabolism are termed "impaired
glucose tolerance," and this is one of the early stages on
the way towards full-blown diabetes.
Habitual sleep restriction could play a very important role
in increasing risk for diabetes later in life, especially if
maintained over many years and decades, much like a sedentary
lifestyle or poor eating habits. It's not something that
catches up with you in a week or in two weeks, but it's
something that over decades can shorten your life.
How can sleeping too much affect body weight?
It's not clear that sleeping too much has anything to do with
increasing body weight. There have been some studies that
have associated very long sleep duration (like 10 hours or
more) on a regular basis, with obesity or weight gain or even
increased mortality. It's not clear at all that it was the
sleep that did that, or if sleep was a symptom of some
unknown health problem.
How does sleep loss affect your food choices?
When the body's rested, you think clearly and you don't have
reduced energy and you're more apt, under those
circumstances, to make wise nutritional choices and to select
something that's healthy for your body. When you're sleep-
deprived, you want to go for an empty calorie energy boost
and usually those are carbohydrates that are very low in
nutrients and very high in calories.
What is the connection between sleep and exercise?
You might be more tired and you won't give your exercise the
intensity that you normally would or maybe you'll skip your
exercise workout. If you're going to be exercising, you need
to rest. When someone switches their sleep pattern to one of
increased deep sleep, they wake up renewed. They don't put
off exercising; they get out of bed, put on their exercise
clothes and go out the door and exercise. And exercise will
help you to sleep deeper and really get into that deep slow-
wave sleep. It is a cycle, and exercise will help them to
sleep better that night, so we think each kind of helps the
Could poor sleep be another risk factor for obesity?
Sleep is just as important as nutrition and exercise in a
healthy diet plan. It's very important to give yourself
adequate sleep. Americans sleep, during the workweek, an
average of 5 hours and 54 minutes, and on the
weekends/Shabbos, they add between 80 minutes to 2 extra
hours per day. So we do go around a little sleep-deprived.
Poor sleep or restricted sleep can potentially be seen as a
symptom of a stressful or unhealthy lifestyle. Adequate sleep
is a sign of a balanced lifestyle along with diet and
exercise. It's been an important recognition that sufficient
sleep is important for good health.
(C) 2005 Dr. Reuven Bruner. All Rights Reserved.
Contact him at: POB 1903, Jerusalem, 91314, Israel; Tel: (02)
652-7684; Mobile: 052 2865-821; Fax: (02) 652-7227; Email: