Summary

Some of us, even those who remain active and eat right, find that we gain unwanted weight as we age. What may be missing is enough sleep. In a study recently published in the Journal of the American Medical Association, lack of deep sleep was associated with decreases in a growth hormone or somatotropin, glycoprotein hormone released by the anterior pituitary gland that is necessary for normal skeletal growth in humans (see protein). Deficiencies in that growth hormone have long been associated with decreases in lean body mass and increases in fat tissue.

A new study was released on May 7, 2008, by the National Center for Health Statistics (part of the Centers for Disease Control and Prevention) which showed that people getting less than 6 hours of sleep or more than 9 hours are more likely to be significantly overweight.

The research adds weight to a stream of studies that have found obesity and other health problems in those who don't get proper sleep.

The study, based on door-to-door surveys of 87,000 U.S. adults from 2004-2006 conducted by the Health Statistics center, found that 33% of those who slept less than six hours were obese, as were 26% of those who slept nine hours or more. People in the seven- to eight-hour group had an obesity rate of 22%.

When you're sleep deprived, it will increase your levels of ghrelin, and when you're sleep deprived it can decrease your levels of another hormone, leptin. Both of those will cause an increase in hunger and a decrease in metabolism, which can lead to obesity.

The hormone factor is an example of sleep deficiency causing a health problem. But doctors say that the reverse also can be the case: Excessive or insufficient sleep might be a symptom of a larger problem.

Obese people are more likely to suffer from sleep apnea because they have more weight on their airways while they are sleeping, which could cause the muscles there to collapse. At the same time, sleep apnea can lead to obesity because people who are chronically tired tend to exercise less and eat more sugary foods in an attempt to wake themselves up.

As we age, our sleep patterns change significantly and most of us find we sleep less and less. In a study from the University of Chicago, 149 healthy men aged 16 to 83 were studied for sleep patterns along with growth hormone. The researchers found that the percentage of slow wave or deep sleep decreased by a factor of more than five and a half times from young adulthood to mid-life.

Cortisol is a hormone that is commonly released in response to physical or emotional stress. When we are deprived of sleep, cortisol is released at an increased level and makes us feel hungry even if we are full. So, people who lose sleep on a regular basis will experience hunger even when they have had an adequate amount of food.

Sleep loss results in less deep sleep, the kind that restores our energy levels. Losing deep sleep decreases growth hormone levels. Growth hormone is a protein that helps regulate the body’s proportions of fat and muscle in adults. With less growth hormone, we reduce the ability to lose fat and grow muscle.

In addition, when you lose sleep, your body may not be able to metabolize carbohydrates as well, which leads to an increased storage of fats and higher levels of blood sugar. Excess blood sugar can lead to insulin resistance. Insulin resistance means that the body has trouble disposing of glucose in the liver and other tissues. It is a trigger for serious health problems such as obesity, cardiovascular disease, and diabetes.

Source: SleepWeb (Marketdata Enterprises, Inc.) research