The Results Are In: Early Risers Actually Are Healthier

According to a recent study funded by the National Institutes of Health and the National Center for Advancing Translational Sciences, researches found that though BMI was unaffected, early risers who got at least 6.5 hours of shut-eye a night were more likely, than late sleepers, to have better diet and eating habits, and are more likely to do more exercise.

Higher fast food and lower vegetable and dairy consumption were associated with late sleep timing in healthy subjects and late biological timing, measured by dim light melatonin onset (DLMO).

Caloric intake, however, was not higher in study participants who slept late and showed late biological timing. In fact, compared to early risers,  late sleepers actually tended to weigh less, noted by researchers led by Kelly G. Baron, PhD, of Feinberg School of Medicine at Northwestern University in Chicago, and colleagues, and presented at this year’s SLEEP 2016 (June 12).

Recruited by telephone or internet outreach, the trial involved 96 healthy people between the ages of 18 and 50 (mean age 26.8, 61% female). All participants reported sleeping at least 6.5 hours a night and none were shift workers.

“This finding suggests that there may be some sort of compensation going on,” she said. “Late sleeping was associated with worse diets, but it was not associated with consuming more calories.”

Wrist actigraphy devices were worn for 7 days by participants to measure both sleep and wake patterns and they also completed food diaries during the study to measure dietary patterns and caloric intake. Exercise levels were measured with physical activity biometric armbands.

The goal of the study was to explore the associations between measures of circadian and sleep timing with body mass index, body fat, and diet and exercise.

Body fat was evaluated using dual axis absorptiometry (DXA), and DLMO was evaluated in the clinical setting.

443.7 (SD 50.4) minutes was the average nightly sleep duration among the participants, and the average DLMO was 22.36±1.27. Most participants had BMIs in the normal range.

Baron said more research will be needed to confirm the findings and, if confirmed, explore how late sleeping leads to poorer quality diets, but not higher BMIs in healthy adults.

“There is some interesting work to be done to unpack the biological versus social factors involved in the health effects of being a late sleeper,” she said.