According to new research, an inconsistent sleep schedule in which a person goes to bed early during the workweek but stays up late and sleeps in on the weekends may increase their metabolic risk. The research team, led by Patricia Wong, a PhD candidate, found that the difference between one’s naturally-preferred and socially-imposed sleep schedules (called social jetlag) was linked to poorer lipid profiles, an increased adiposity in health adults, and worse glycemic control. The study included 447 healthy adults ages 30 to 54 years of age who worked either part- or full-time day shifts.

The participants were 53% female and 83% white. Subjects wore an actigraph wristband that measured their movement and sleep 24 hours a day for 7 days, and the researchers collected blood samples for laboratory tests and assessed participants’ diet and exercise habits via questionnaire, according to Medpage Today. The sleep schedules of the participants on their days off from work were compared with their sleep schedules on workdays. The difference between the midpoint of the two sleep schedules was defined as social jetlag.

The researchers looked for associations between cardiometabolic risk factors and social jetlag. The results revealed that 111 study participants had a social jetlag of more than 60 minutes, and compared to the other participants, these individuals had the following: higher mean triglycerides; lower mean HDL-cholesterol; higher mean fasting insulin levels; more insulin resistance; greater mean waist circumference; and higher mean body mass index.

The Medpage Today news release notes that while all study participants had some degree of social jetlag, those who stayed up later and slept in on their days off had a greater degree of social jetlag.

“Our results in this study, in conjunction with recent research conducted throughout other countries, suggest that even healthy, nonclinical populations may be experiencing important, regular shifts in their sleep cycle that is unfortunately working ‘against’ their biological clock,” Wong states. “If future studies replicate what we found here, then we may need to consider as a society how modern work and social obligations are affecting our sleep and health,” Wong said.

Wong adds, “There could be benefits to clinical interventions focused on circadian disturbances, workplace education to help employees and their families make informed decisions about structuring their schedules, and policies to encourage employers to consider these issues.”

Source: Medpage Today