Sleep deprivation can increase the chances of becoming obese in several ways. People who are sleep deprived may be too tired to exercise, which decreases the “calories burned” side of the weight change equation. Or people who do not get enough sleep can absorb more calories than those who do, simply because they are awake longer and have more opportunities to eat; lack of sleep also upsets the balance of key hormones that control appetite, so sleep deprived people may be hungrier than those who get enough rest each night. The researchers hypothesized that the release of fat stores is a mechanism for which sleep is promoted, and that the reason KIN-29 mutants did not sleep is because they were unable to liberate their fat. To test this hypothesis, the researchers again manipulated the KIN-29 mutant worms, this time expressing an enzyme that “freed” their fat. With that manipulation, the worms were again able to sleep.
“There is a common, over-arching sentiment in the sleep field that sleep is all about the brain, or the nerve cells, and our work suggests that this isn’t necessarily true,” researcher said. “There is some complex interaction between the brain and the rest of the body that connects to sleep regulation.”
“If a person is overweight and suffering from sleep-disordered breathing, he/she may not be as motivated to exercise or to diet. When apnea leads to daytime sleepiness, it may be that much harder to begin or sustain an exercise program, which has been shown to help people begin or maintain weight loss.” Not only does obesity contribute to sleep problems such as sleep apnea, but sleep problems can also contribute to obesity. A 1999 study by scientists at the University of Chicago found that building up a sleep debt over a matter of days can impair metabolism and disrupt hormone levels. After restricting 11 healthy young adults to four hours’ sleep for six nights, researchers found their ability to process glucose (sugar) in the blood had declined—in some cases to the level of diabetics.
A follow-up study tested healthy men and women with an average body mass index; half were normal sleepers, the other half averaged 6 1/2 hours or less. Glucose tolerance tests showed that the short sleepers were experiencing hormonal changes that could affect their future body weight and impair their long-term health. To keep their blood sugar levels normal, the short sleepers needed to make 30% more insulin than the normal sleepers. Both studies were led by Eve Van Cauter, PhD, who termed sleep deprivation “the royal route to obesity. Despite not yet being overweight,” she said, “these young adults had profiles that predisposed them to putting on weight.”
Sleep experts say there are a number of things you can do to lose weight and improve your sleep:
- Make healthy choices for your meals. Avoid fast foods. Eat more fish, fruits and vegetables; avoid foods high in carbohydrates or fats.
- Start getting consistent exercise, which will improve the quality of your sleep. Most experts, however, say to avoid exercising less than 3 hours before bedtime, because exercise is alerting and can make it harder to fall asleep.
- Examine your sleep schedule. Are you getting at least 7 hours of sleep each night? Do you wake up feeling refreshed or lethargic? Do you wake up frequently during the night? Are you underweight, overweight, or just right?