Christian Finn's Weekly Research Update
http://thefactsaboutfitness.com/

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1. RESEARCH UPDATE: Sleep And Weight Loss
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"The link between sleep and weight loss most people don't know
about..."

A combination of diet and exercise is usually the method of
choice for people who want to control their weight. Strange as it
might sound, there's also a growing body of evidence to show that
better sleep habits are instrumental to the success of any weight
loss plan.

A fascinating series of studies published in the Journal of the
American Medical Association and the Lancet show that sleep loss
disrupts a series of complex and interwoven metabolic and
hormonal processes. This can make weight loss far more difficult
than it needs to be.

When most people hear the word "hormone", they think of the sex
hormones, such as testosterone or estrogen. Yet these are just
two of the many hormones that regulate virtually everything your
body does. Hormones have the power to change the way your fat
cells respond to the food you eat. Specifically, sleep loss
affects levels of cortisol, growth hormone and insulin.

Cortisol is a hormone released by your adrenal glands in response
to either physical or emotional stress. Whether it's an extremely
low calorie diet, missed nights of sleep, or getting caught in a
traffic jam, your body responds in much the same way. When you
deprive your body of sleep, cortisol levels tend to rise,
especially in the evening. This, in turn, raises insulin
levels. Insulin promotes a metabolic environment that
encourages the storage of fat.

Picture the scene. You come home from work late in the evening.
Not only have you been having trouble sleeping, work is also
causing stress. So you decide to eat something that will make you
feel better.

Consider the type of food people crave when they feel stressed -
rich in refined carbohydrate and sugar. Combine a stress-induced
chocolate binge with elevated levels of cortisol and insulin, and
you have the perfect recipe for weight gain.

Sleep deprivation, even for as little as 24 hours, can also lead
to signs of insulin resistance. Insulin resistance means that the
ability of insulin to dispose of glucose in the liver and other
tissues is reduced.

Scientists point to insulin resistance as the "trigger" for a
host of health problems, including obesity, cardiovascular
disease, and type II diabetes. Insulin resistance is the
cumulative effect of poor eating and lifestyle habits. In fact,
there is evidence that rats show signs of insulin resistance
after just two weeks on a high-fat, high-sugar diet.

A decline in slow wave sleep (this is the "deep" sleep known for
its restorative properties) is also linked with reduced levels of
growth hormone. This hormone plays an important role in fat loss
and muscle growth.

Further evidence linking body weight and sleep comes from a study
of 814 men and 958 women from the Mediterranean area of Spain.
Carried in the International Journal of Obesity, the study
shows that people who sleep for more than nine hours each day are
less likely to be overweight than those sleeping for six hours or
less. Based on their findings, the authors conclude that the odds
of obesity are 24% lower for each additional hour you spend
asleep.

The results also show that people watching TV for more than four
hours each day were more likely to be obese than those watching
TV for less than one hour. In fact, the odds of obesity are 30%
higher for each hour you spend in front of the TV.

Of course, this research doesn't mean that sleeping for less than
six hours each night is a guarantee that you'll put on weight.
Nor does it mean that sleeping for longer is the answer. As with
many things, the relationship between sleep and fatigue is
probably U-shaped. The same holds true with many nutrients, where
excess amounts can be toxic. But if you don't get enough, your
health suffers. In other words, too little, as well as too much
sleep is not healthy.

What's most important is to recognize that a healthy lifestyle
involves balancing work and rest in a way that suits you. Getting
enough sleep and rest is just as important as what you eat and
how you exercise.