When it comes to sleep patterns, "lark" is a term often given to people who like to get up early. An "owl" is someone who likes to stay up late. While a lark may be ready for bed well before 10 p.m., an owl may wish the day started at 10 a.m. Whether you are a lark or an owl, are you getting enough sleep?
Doctors have known for many years that lack of sleep can cause foggy thinking and poor concentration. More recent research has shown that lack of sleep can also lead to potentially serious health problems. A chronic lack of sleep can place you at risk for developing several of the diseases associated with poor eating habits and physical inactivity.
Cortisol, a stress hormone that regulates the blood sugar glucose, seems to be one of the hormones to blame. Prolonged sleeplessness causes the body to continuously release cortisol into the bloodstream. This, in turn, causes a rise in glucose in the blood that prompts the body to release more and more insulin in an attempt to lower the glucose level. Insulin is a hormone that lets glucose enter the body’s cells, where the sugar is burned for energy. Over time, the increased production of insulin leads to insulin resistance or metabolic syndrome, a condition in which the cells no longer respond to the effects of insulin. This condition has a cluster of symptoms that increases the risk of heart attack, stroke and diabetes. Signs of the syndrome are abdominal obesity, low HDL “good” cholesterol, and elevated, though not necessarily high, triglycerides, blood pressure and blood sugar.
Additionally, getting too little sleep can boost your appetite by lowering leptin and raising ghrelin levels. Leptin, a hormone released by fat cells, signals the brain to stop eating. Ghrelin, a hormone that is made in the stomach, pushes you to eat more. The two influence whether you go for a second helping or push yourself away from the table. The brain also interprets a drop in leptin as a sign that you are starving. So it responds not only by boosting hunger, but by burning fewer calories. Studies have shown that leptin levels are lower and ghrelin levels are higher in people who sleep fewer hours. So, too little sleep may make you hungry, especially for calorie-dense foods, and may prime your body to try to hold on to the calories you eat.
One particular study, conducted at the University of Chicago, noted that the men said that they were more hungry, and that they would be more likely to eat salty foods like chips and nuts, sweets like cake, candy, and ice cream, and starchy foods like bread, cereal, and potatoes after four hours of sleep than after ten hours.
A presentation at the International Conference of the American Thoracic Society held in San Diego in June reported the results of a 16-year study of 68,183 middle-aged women. The women who slept five hours or fewer each night were 32 percent more likely to gain a significant amount of weight, in some cases, as much as 33 pounds, and 15 percent more likely to become obese, compared to women who slept seven hours a night.
The chronic release of stress hormones caused by sleep deprivation affects your immune system, making you more susceptible to colds and infections. Also, because your immune system helps your body to fight cancer, reduced immune system function from insufficient sleep can put you at increased risk of developing cancer.
Chronic lack of sleep can also accelerate the aging process. When you don't get enough sleep, your brain doesn't make the normal amounts of hormones, producing hormone levels similar to those of a much older person. However, subsequently getting a full night's sleep reverses this aging effect, returning hormone levels to normal.
So how much sleep is enough? According to the National Sleep Foundation, the most natural cycle of sleeping and waking is 16 hours of daytime and evening activity, followed by 8 hours of sleep at night. To test yourself, take the following quiz.
National Sleep Awareness Week was this past March. I guess we missed it. I hope you and I were both sleeping.
Are You Sleep Deprived?
Rate the following statements: 0 = Never; 1 = Sometimes; 2 = Often; 3 = Always
___ I sleep through the alarm clock.
___ I have morning grogginess.
___ I need caffeine to help me wake up in the morning.
___ I need caffeine to help me stay awake during the day.
___ I have difficulty concentrating.
___ I turn down social engagements because of fatigue.
___ It is difficult to keep my eyes open while driving at night.
___ I fall asleep within 5 minutes of going to bed.
___ I am forgetful during the day.
___ I am irritable with family members and co-workers.
___ It takes me longer to get things done.
___ I experience the mid-afternoon slump.
___ TOTAL
SCORING KEY
0 – 15 No, you are not sleep deprived.
16 – 24 You are on the way to sleep deprivation.
25 – 36 Yes, you are sleep deprived.
Sources:
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Family Medical Guide, Fourth Addition, American Medical Association, 2004
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Weill Medical College of Cornell University Food and Fitness Advisor, August, 2006
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Center for Science in the Public Interest Nutrition Action Health Letter, July/August, 2006 and July/August, 2005
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