Changes in sleep patterns throughout the week could lead to an increased risk for metabolic problems like diabetes and cardiovascular disease (CVD), according to a study published in Journal of Clinical Endocrinology & Metabolism.
Shift workers are more likely to develop cardiometabolic issues like coronary heart disease (CHD) and type 2 diabetes than employees with regular workday schedules because of the repeated disruption to the circadian system, according to background information in the study. The disjunction between the circadian rhythm and a socially imposed sleep schedule is referred to as “social jetlag.”
“Other researchers have found that social jetlag relates to obesity and some indicators of cardiovascular function,” said Patricia Wong, MS, of the University of Pittsburgh, in a press release.
“However, this is the first study to extend upon that work and show that even among healthy, working adults who experience a less extreme range of mismatches in their sleep schedule, social jetlag can contribute to metabolic problems. These metabolic changes can contribute to the development of obesity, diabetes, and cardiovascular disease.”
Participants were between the ages of 30 and 54 who took part in the Adult Health and Behavior Project phase 2 study and worked at least 25 hours per week. They wore wristbands that measured movement 24 hours a day for a week and answered questionnaires to assess diet and exercise patterns.
Researchers calculated social jetlag with the difference in minutes between the midpoints of actigraphy-derived sleep intervals before a workday and before a non-workday.
Of 447 participants (mean age, 42.7 years; 53% women; 83% white), 84.8% had later midpoints in the sleep cycle on their free days compared with workdays. This suggests a circadian phase advance in their sleep timing when transitioning from work to free days. Conversely, 15.2% had earlier midpoints on free days.
Participants with increased social jetlag tended to have lower HDL cholesterol levels, higher triglycerides, higher fasting plasma insulin, insulin resistance, and adiposity than participants with less social jetlag (P<.05). The results were consistent after adjusting for sleep duration and quality, physical activity, and calorie intake.
“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,” said Wong. “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.”