The twin epidemics of diabetes and obesity might be connected with our increasing sleep deprivation. But how?
A professor at UC San Diego's School of Medicine and her colleagues determined to find if they might be related. Ruth Patterson, Ph.D., led a unique study that just came out and finally offered some tested answers.
This study used state-of-the-art methods to estimate energy intake and output and then compared these factors to typical sleep duration in a group of healthy men and women. The study, "Short Sleep Duration Is Associated with Higher Energy Intake and Expenditure among African-American and Non-Hispanic White Adults," will be published in the April 2014 issue of The Journal of Nutrition, but an abstract went online February 14. Professor Patterson kindly provided me with the full-text.
Earlier studies showed that diabetes and obesity have some connection. Most obvious is the well-documented fact that more than 85 percent of American adults who have diabetes are also overweight. That's quite a bit more than the 69 percent of all American adults who are overweight, according to the U.S. Centers for Disease Control and Prevention. This connection doesn't prove that weight leads to diabetes, of course. The fact that correlation does not imply causation is a basic principle of science. In fact, the connection between diabetes and weight may both be the result of a third factor, something that I argued in my second book, Losing Weight with Your Diabetes Medication.
This third factor might be connected with getting too little sleep. Earlier studies also showed that short sleep duration is connected with type 2 diabetes, insulin resistance, and other chronic diseases, as the new study points out. "The data are especially strong regarding the association of short sleep duration with weight gain and obesity."
But does lack of sleep cause weight gain or does weight gain results in difficulty sleeping? Earlier studies didn't answer this chicken-and-egg question. In addition, measuring the two key factors related to weight gain has lots of difficulties. Many people report that they eat less than they actually do, and those who weight more generally underreport even more. Self-reporting of how much activity people get is also fraught with errors. To circumvent these limitations in previous studies, this is the first one to test the influence of objectively measured energy intake (food) and physical activity (exercise) under free-living conditions (not in a laboratory setting).
This new study gave a sizable group of 223 people small doses of stable (nonradioactive) isotopes of water enriched with minute quantities of naturally-occurring but slightly heavy atoms of hydrogen and oxygen. The researchers used the appearance of these isotopes in the urine of the people in the study to estimate their total energy expenditure. In turn that made it possible to determine their energy intake and activity levels.
The results indicated that people who got six or fewer hours of sleep per night had the highest levels of obesity and consumed the most calories on a daily basis. Although people who slept less also expended more calories in physical activity, this wasn't enough to compensate for eating more.
The implication of the new research is that people who are overweight or obese and aren't able to manage their diabetes might do well by addressing what may be a contributing factor. Many of us, whether or not we have diabetes, aren't getting enough sleep.
Almost two-thirds of all Americans say their sleep needs aren't being met during the week, according to a poll that the American Sleep Foundation recently conducted. Most people said that they need about seven and a half hours of sleep to feel their best, but report getting about six hours and 55 minutes of sleep on average weeknights.
But, "Sleep habits are amenable to improvement," as the new study emphasizes in its conclusion. Maybe it's as straightforward as voluntarily sleeping longer. Some of us suffer from sleep disorders such as insomnia, which may call for a visit to a doctor. Perhaps even more likely for those of us who have diabetes the problem is the pervasive connection we have to sleep apnea.
Whatever the problem, we can each test whether getting more sleep can lead to losing weight and whether that in turn makes it easier to manage our diabetes.