Good sleep habits are important for overweight adults, OHSU study suggests 

Results show gender-specific health effects in people who work late into the night 

A sign glows in a dark room saying, "Please be quiet, sleep study ongoing." New OHSU research shows that overweight people who stay awake  for long periods of time, which disrupts their body clock, have negative health effects. (OHSU/Christine Torres-Hicks) 

 New OHSU research shows that overweight people who stay awake  for long periods of time, which disrupts their body clock, have negative health effects. (OHSU/Christine Torres-Hicks) 

New research from Oregon Health & Science University shows that overweight people who  ignore their body's signals that they want to sleep at night have negative health effects, with specific differences between men and women. 

The study was published this week in the Journal of Clinical Endocrinology & Metabolism. 

Dr. Brooke Shaffer has her dark blonde hair pulled back in a low bun and is wearing a lab coat in a sleep lab equipped with beds and equipment. Brooke Schafer, PhD

"This study highlights the importance of good sleep habits," said lead author Brooke Schafer, PhD, a postdoctoral researcher in the OHSU School of Nursing's Sleep, Chronobiology and Health Lab. "Sleep habits like going to bed when you're tired and putting away your screen at night can help  promote  overall health." 

The study included 30 people, evenly split  between men and women. All had a BMI over 25, placing them in the overweight or obese category. 

"weight problems and cardiometabolic sickness are growing public health troubles," Schafer stated. "Our study shows that disruption of the body clock may negatively impact the health of people who are already  vulnerable because of their weight." 

Generally healthy participants provided saliva samples every 30 minutes during the night at the sleep lab on OHSU's Markham Hill campus to measure the time  their bodies naturally start producing the hormone melatonin. Melatonin is generally believed to trigger the sleep process, the onset of which depends on an individual's biological clock. 

The participants then went home and recorded their sleep habits for the next seven days. 

The researchers measured the time difference between each participant's melatonin onset and their average sleep time and categorized the participants into two groups: those with a narrow window, meaning a short time  between melatonin onset and sleep, and those with a  longer window between melatonin onset and sleep. A narrow window indicates staying awake for too long relative to the biological clock and is generally associated with poorer health. 

The new study identified a number of potentially harmful behaviors in the group who went to bed closer to the start of their melatonin dose. Important differences between men and women were also noted. Men in this group had higher levels of abdominal fat and blood fat triglycerides  than  men who slept well, and had a higher overall risk of metabolic syndrome. Women in this group had higher total body fat, blood glucose levels, and resting heart rates. 

 "It was really surprising that we saw these differences in a gender-dependent manner," said lead author Andrew McHill, PhD, assistant professor in the OHSU School of Nursing,  School of Medicine and Oregon Occupational Health Institute, and professor of science at OHSU. "There is no one-size-fits-all solution, as is sometimes thought in academic medicine." 

 The next phase of the study will identify sex differences in groups that show greater changes in sleep patterns, such as night-shift workers. 

 "We hope to identify possible interventions to keep this important core group of the workforce healthy," Schafer said. 

 This research was supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health (awards T32HL083808, K01HL146992, R01HL105495, R35HL155681); and the NIH National Center for Advancing Translational Sciences (awards UL1TR000128, UL1TR002369); and the Oregon Institute of Occupational Health Sciences at OHSU, with funding from the Oregon Department of Consumer and Business Services  (ORS 656.630).  The content is purely the responsibility of the authors and does not always constitute the professional perspectives of the countrywide Institutes of fitness.