18). Ultimately, this nasty cycle raises your risk for type 2 diabetes, which accelerates aging in almost all of your body’s systems (55).Can you lose weight while you sleep? It’s not just a dream—an increasing body of evidence shows that sleep plays a role in weight gain and obesity. In particular, researchers have recently turned their attention to two hormones that control appetite: ghrelin and leptin. Ghrelin, produced in your gastrointestinal tract, triggers hunger. Leptin is produced in fat cells and tells your brain when you’re full. And sleep affects the production of both.
As you get older, your sleep habits may change. Studies show that circadian rhythms, which manage your sleep/wake cycle, shift with age. That’s why even former night owls frequently find themselves going to bed and waking up earlier, spending less time in deep sleep, and sleeping less overall. And according to the National Sleep Foundation, up to 80 percent of older adults with four or more health problems report not sleeping well. These changes, combined with an increased risk of insomnia and sleep disorders as you get older, can throw off ghrelin and leptin levels, frustrating even the best-laid weight loss plans. (Studies also show that estrogen affects ghrelin production, so women in midlife may have an even harder time, thanks to fluctuating hormones.)
Too little sleep disrupts the hormonal balance in two ways. It lowers leptin levels, meaning you don’t register the feeling of fullness that signals you to stop eating. But it also raises ghrelin levels, which can make you ravenous. University of Chicago researchers examined the ghrelin and leptin levels of twelve men after two days of restricted sleep and then two days of extended sleep. Not only did they find that the men’s ghrelin levels were higher and leptin levels lower after sleep restriction, making them hungrier, but the men also had cravings for high-calorie, high-carb foods. A 2009 study in the American Journal of Clinical Nutrition tried a similar approach, restricting the sleep of middle-aged men and women to just 5.5 hours a night for two weeks. They found that the volunteers took in about 300 more calories from high-carb snacks per day than they did during a two-week period when they slept for 8.5 hours. Even more revealing, Stanford researchers looked at the sleep habits of more than one thousand people and found that the less sleep they got, the higher their BMI.
In 2010, researchers at the University of Chicago reviewed studies noting the connection between lack of sleep and obesity. In addition to the ghrelinleptin link, they found that not getting enough shut-eye can reduce insulin sensitivity. Insulin helps your cells use blood sugar (glucose) for fuel and also converts calories into fat. As your body becomes less sensitive, your pancreas has to pump out increasingly greater levels of insulin to make sure your cells get enough glucose and to keep your blood sugar normal. That extra insulin also means more calories get stored as fat, and as you get older, the double whammy of insulin and aging makes it more likely that the fat gets stored in your abdomen (18). Ultimately, this nasty cycle raises your risk for type 2 diabetes, which accelerates aging in almost all of your body’s systems (55).
Sleep timing, duration, and quality all play a role in keeping your hormones balanced. Try to doze off and wake up at approximately the same time every day, including weekends. To reset your sleep schedule, gradually head to bed fifteen minutes earlier and/or set your alarm for fifteen minutes later, until you’ve carved out seven or eight hours for sleeping. Light signals your brain that it’s time to sleep or wake up, so about an hour before bedtime, dim the lights. Keep your bedroom dark at night; purchase light-blocking shades if necessary. As you get older, nighttime bathroom breaks frequently increase; install a night-light to avoid using the bright overhead light, which can make falling asleep again harder. In the morning, open your shades to let in sunlight.
If you already get enough sleep and still feel tired (and hungry) all the time, ask your doctor if you might have obstructive sleep apnea. Your risk increases as you get older, so it’s worth looking into even if you’ve never had problems sleeping in the past. Apnea can cause you to stop breathing for short periods, sometimes hundreds of times a night. This disrupts your sleep and can leave you feeling groggy during the day even if you spent eight or nine hours in bed.