I'm a notoriously bad sleeper. I go to bed too late, wake up throughout the night and always bank on catching extra zzz's on the weekend. Apparently I'm not alone.
Twenty eight percent of American adults sleep six or fewer hours per night. What's more alarming is that partial sleep deprivation has been linked to many chronic conditions, including obesity, diabetes and cardiovascular disease. Could years of poor sleeping patterns be affecting my eating habits and health?
There is plenty of scientific evidence that associates short sleep duration with weight gain. The more time we spend awake, the more opportunities we have to eat. Add to that a lack of motivation to hit the gym when we're tired. Partial sleep deprivation may also influence two hormones that affect appetite. The jury's still out, but many studies have shown that sleep shortage increases ghrelin, which induces hunger, and reduces leptin, thereby lessening satiety.
In a study to be published later this year, researchers looked at how eight nights of sleep restriction affected hormone levels and caloric intake in 17 healthy, normal weight adults. Despite no significant changes in leptin and ghrelin, participants limited to sleeping two-thirds their usual duration consumed an average of 566 more calories per day compared with their energy intake under ad lib sleeping conditions.
In a separate study of obese adults, participants ate an extra 83 calories per day for every 30-minute reduction in sleep. Therefore, sleeping just one hour less than the recommended 7.5 hours per night could translate into a 17-pound weight gain per year if no compensation occurs!
Cutting short a snooze may also negatively affect glucose metabolism and insulin sensitivity, although these results are not universally observed. In a 2011 study published in Sleep, 15 healthy, normal weight men had significantly greater peak insulin and glucose responses to breakfast after two nights of sleep restriction (four versus eight hours in bed).
More research is needed to clarify how sleep deprivation affects endocrine function, but chronically catching too few winks may create the perfect storm for overconsumption. Of all sedentary activities, sleeping is clearly one with positive health benefits!
Whether we're counseling an overweight client or reflecting on our own vices, we should all aim to rest 7 to 8 hours a night.
