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Medical and Health Notes
Sleep deprivation and fatigue
How "Sleep Debt" Affects Your Health
By Dr. W. Gifford Jones
Tuesday, June 7, 2005
William Shakespeare, in his play Julius Caesar, referred to sleep as "the honey-heavy dew of slumber". Just reading this makes me drowsy. But for millions of people a good night's sleep is elusive. And new research shows that insomnia may lead to several chronic diseases.
A report from Tufts University reminds us that the greatest disasters in recent history, the explosion on the Challenger space shuttle, the crash and spill of oil by the Exxon Valdez and the Chernobyl nuclear disaster were related to sleep deprivation and fatigue. And that thousands of car accidents share the same cause.
Dr. William Dement, a renowned sleep researcher at Stanford University in California, says there is compelling evidence that how well and how long you sleep is an important indicator of how long you live.
So how much sleep do we need? An English proverb claims "Six hours for a man, seven for a woman and eight for a fool." But according to The National Sleep Foundation whether you're man, woman or fool eight hours of sleep is required for health, safety and performance. But only one-third of us gets that amount and the invention of the light bulb started this downward trend.
So what happens if you suffer from chronic insomnia? During sleep none of us go into a state of hibernation. Rather, there are changes in levels of hormones and blood pressure. Researchers believe that sleep allows time for the body to repair itself. And that getting short-changed by insomnia increases the risk of disease.
For instance, the Nurses Health Study at Harvard Medical School followed 70,000 nurses for 10 years to detect a variety of health problems. Just hearing of its results might give some people insomnia.
Women who slept for 6 hours had an 18 percent increased risk of heart attack compared to those who slept 8 hours. For women who slept 5 hours the risk jumped to 39 per cent. But sleeping longer was no help. Women who slept for 9 hours also had an increased risk of coronary attack.
Sleep apnea, during which breathing temporarily stops several times a night, poses other problems. Deprivation of oxygen to the brain causes the blood pressure to rise and the heart to beat faster.
This research brings more bad news to those suffering the current epidemic of diabetes. A group of young men at the University of Chicago was subjected to just 4 hours of sleep a night. This caused an increase in blood sugar and a decrease in the secretion of insulin, resulting in a 40 percent decrease in the rate sugar was cleared from the blood.
Insomnia is also no friend of those trying to lose weight. Sleep debt increases the appetite and food consumption. How this happens is not certain. But a hormone, leptin, is believed to provide that good feeling when we've had sufficient food. Sleep deprivation decreases the amount of leptin and causes a craving, particularly for carbohydrates.
Tossing in bed at night also diminishes the amount of growth hormone. This hormone is critical to cell repair and healing in adults and also helps to control the amount of fat and muscle in the body. Growth hormone decreases with aging but insomnia adds to the problem.
If you are part of the yawning majority and feel "run down" due to lack of sleep, your immune system is not in fighting shape. A University of California study showed that when 42 healthy men were deprived of just one night of partial sleep the following day the immune system was less effective. They found that "natural killer cells" which fight viral infections and cancer were compromised.
To fight insomnia, experts advise establishing a sleep routine even on weekends. Don't fight going to bed when you feel sleepy, and keep the bedroom cool. Warm milk and a bath helps some people to slumber. But avoid an alcoholic nightcap, which initially causes drowsiness, but disrupts sleep during the night. And don't watch a Dracula movie before bedtime! If you're not asleep in 20 minutes, get up, and read a book and have a small snack if you feel hungry. Then, finally, like Shakespeare, you may "Sleep, perchance to dream".
W. Gifford-Jones M.D is the pen name of Dr. Ken Walker graduate of The Harvard Medical School. He's been a ship's surgeon, hotel physician and family doctor and later trained in surgery at McGill in Montreal, University of Rochester N.Y. and Harvard. His medical column is published by 60 Canadian newspapers and several in the U.S. He is the author of seven books. Dr. Walker has a medical practice in Toronto. His Web site is: www.mydoctor.ca/gifford-jones. He can be reached at letters@canadafreepress.com
