The Link Between Obesity and Abnormal Sleep Patterns

Overweight adults who experience excessive fatigue may not be tiring out simply because of the extra weight they are carrying around. Several studies have linked obesity with abnormal sleep patterns and disorders such as obstructive sleep apnea.

Though researchers have yet to determine causality (does the extra weight cause the poor sleep patterns, or vice versa?), there is an abundance of evidence pointing to the fact that overweight adults are disproportionately exposed to the health risks associated with getting abnormal amounts of sleep.

As the following excerpts from three studies demonstrate, a sleep deficit of as little as 16 minutes per night can correlate to an increased likelihood of overweight. Poor sleep habits even appear to offset the effect of consuming fewer calories.

• The National Health and Nutrition Examination Survey I, which studied 9,000 adults from 1982 to 1984 and then conducted a follow-up survey with them in 1987, found that study participants who slept five hours or less per night were 73 percent more likely to become obese than were subjects who got get seven to nine hours of sleep nightly. Those who slept six hours per night were 27 percent more likely to become obese than were the seven-to-nine-hour group.

• Researchers from Case Western University who studied the sleep habits of more than 68,000 women found those who slept fewer than five hours per night gained more weight than did the women who got at least seven hours of shuteye every night. Perhaps most surprising was the fact that, on average, the women in the five-hours-or-less category took in fewer calories on a daily basis than did the longer sleepers, yet were still more likely to become obese.

• A study conducted by Eastern Virginia Medical School (published in the Jan. 10, 2005 issue of Archives of Internal Medicine) found that, among the 1,000 individuals who were involved in the study, the amount of time they reported sleeping per night decreased as body mass index increased. Overweight or obese subjects slept an average of 16 fewer minutes per night, which added up to a weekly sleep deficit of one hour and 52 minutes.

In addition to a relationship between high body mass index and poor sleep, researchers have also documented a strong connection between obesity and obstructive sleep apnea, a potentially life-threatening disorder in which sufferers experience repeated periods of oxygen deprivation while sleeping. Individuals with sleep apnea stop breathing for 10 seconds or more at a time - a disruption that can repeat itself hundreds of times each night. In addition to the fatigue associated with sleep deprivation, sleep apnea has also been linked to a wide range of health disorders, including hypertension, memory problems, immune system abnormalities, and acid reflux.

There are two types of sleep apnea:

• Central sleep apnea - In this form, which occurs in about 10 percent of sleep apnea sufferers, the part of the brain that controls respiration fails to prompt the muscles that are necessary for inhalation and exhalation, causing increased carbon dioxide levels and decreased oxygen levels in the sleeper's blood. When the oxygen levels fall far enough, the brain signals the body to wake up and breathe.

• Obstructive sleep apnea - Nine out of 10 sleep apnea sufferers exhibit symptoms of this form, in which the sleeper's air passage becomes blocked (usually by the tongue, uvula, tonsils or fatty tissues in the neck). Individuals with obstructive sleep apnea often snore (though not all snorers suffer from sleep apnea), and often awaken gasping for air.

Individuals afflicted with both types of sleep apnea may awaken hundreds of time per night in order to breathe, yet they may not remember any of these events in the morning - though they will likely suffer from symptoms of sleep deprivation (such as fatigue and a propensity for falling asleep throughout the day).

Because sleepers may have no memory of their snoring, gasping, or multiple awakenings, sleep apnea may go undiagnosed and untreated for extended periods of time. Often, the disorder's symptoms are first noticed by a person who shares living quarters or sleeping space with the apnea sufferer. Lab tests, X-rays, and thorough physical examinations can help medical professionals determine if one is likely to have sleep apnea, but a definitive diagnosis is dependent upon observation of the patient's sleep patterns during an overnight stay or stays in a sleep lab.

Various experts and studies indicate that as many as 95 percent of individuals who have sleep apnea are overweight or obese. And though a definitive causal relationship between obesity and apnea has yet to be established, the National Heart Lung and Blood Institute reports on its website that a reduction in a person's weight has been associated with a similar reduction in severity of sleep apnea, as well as a lowering of the person's blood pressure. "Both medical and surgical studies have demonstrated that as little as 10 percent weight reduction is associated with a more than 50 percent reduction in the severity of sleep apnea," the NHLBI reports.

Disorders such as sleep apnea require medical intervention to alleviate their symptoms, but the experts at the National Sleep Foundation advise that there are a number of steps that all adults can take to increase their odds of getting a good night's sleep:

• Establish a consistent sleep time. Try to go to bed and get up at the same times every day (even weekends and holidays).

• Avoid caffeine, chocolate, and other stimulants (including nicotine) in the hours leading up to bedtime.

• Avoid alcohol before bed. Yes, it's a depressant, and as such it may help you fall asleep. But alcohol-induced sleep is more likely to be shallow, with disrupted dream patterns and a greater likelihood of earlier awakening.

• Follow a relaxing routine before going to bed. This may include a soak in a warm tub, soothing music, or a few moments with a good book - whatever helps ease your mind and relax your body.

• Keep your bedroom cool, dark, and as quiet as possible.

• Hide your clock. That bright digital display may be a distraction - but even a subdued timepiece may inhibit your ability to fall asleep by adding a degree of stress as you watch the minutes tick away. Set your alarm, then turn the clock toward the wall, or put it in a drawer.

• Exercise. Individuals who are active during the day are more likely to sleep more regularly (and better) at night.

Legendary American football coach Vince Lombardi once underscored his rationale for putting his players through a notoriously demanding conditioning program by observing that "fatigue makes cowards of us all."

Though Lombardi was likely thinking more about wind sprints and fourth-quarter surges than warm baths and comfy pillows, studies solidifying the link between obesity and poor sleep continue to document the ways in which the effects of fatigue can be even more detrimental to an overweight individual's health than to a championship team's performance.

The good news is that improvements in either of these areas can have a "two-for-one effect" - that is, reducing one's body mass index seems to have a positive impact on one's sleep patterns, and vice versa. Through education, behavior adjustments, and consultations with experts in the two fields, overweight individuals and those who suffer from sleep disorders have the opportunity to improve their health and enhance their quality of life.

Sources

• "Body weight and sleep" (http://www.sleepdex.org/weight.htm)

• "Helping Yourself to a Good Night's Sleep" (http://www.sleepfoundation.org/site/c.huIXKjM0IxF/b.2421167/k.238/Helping_Yourself_to_a_Good_Nights_Sleep.htm)

• "Insufficient sleep associated with overweight, obesity" (http://www.sciencedaily.com/releases/2005/01/050111114820.htm)

• "Obesity and Sleep Apnea" (http://www.nhlbi.nih.gov/guidelines/obesity/e_txtbk/appndx/apndx4.htm)

• "Sleep Apnea Information" (http://www.sleepapnea.org/info/index.html)

• "Sleep Apnea and Obesity" (http://www.weight.com/sleep.asp)

• "Sleep Apnea: Symptoms, Causes, Diagnosis, and Treatment" (http://www.helpguide.org/life/sleep_apnea.htm)

• "Sleep more to fight obesity" (http://www.webmd.com/diet/news/20041116/sleep-more-to-fight-obesity)