A great number of observational studies have suggested that sleep loss or disrupted circadian rhythms due to shift work are associated with obesity, type 2 diabetes and a variety of other dysfunctional metabolic conditions. A study from Uppsala University is now offering evidence that helps better explain how tissue-level molecular changes are brought on by sleep loss.
It's becoming clearer and clearer that disruptions to our circadian rhythms and interrupted or bad sleep can have a variety of negative health outcomes. Earlier this year a very large observational study concluded that night owls who tend to stay up late have a higher mortality risk and higher rates of diabetes and psychological or neurological disorders.
Obesity and weight gain have long been associated with bad or irregular sleep, and the most common hypothesis explaining this correlation was that chronic sleep deprivation tends to lead to inconsistent eating patterns and greater overall caloric intake. But what if these negative health outcomes are not simply due to eating junk food late at night? What if sleep loss actually results in more direct metabolic alterations at a tissue level?
A small study from a few years ago compared two groups of overweight subjects undergoing moderate caloric restriction. Over two weeks one group was limited to around five hours of sleep a night while the other group was allowed the minimum eight hours. The results found that the sleep deprived group struggled to lose as much weight as the control group suggesting that even with caloric restrictions, sleep loss can drastically alter a person's metabolism.