Do you get up early on weekdays and then sleep late on Saturday and Sunday? This changing of your sleep pattern may be bad for you.
There have been several studies have found an association between shift work, especially working at a job where you shift, and thus the hours you sleep, changes regularly, and an increased risk for heart disease and diabetes. Now, a new study has found a similar association in people who change their sleeping schedules on the weekend. This weekday to weekend change is called social jetlag.
For the study, researchers at the University of Pittsburgh enrolled 447 people aged 30 to 54 who worked either part-time or full-time. They were assessed for their chronotype, which means finding out what time of day they preferred sleeping. For seven days, the participants wore devices that measured movement and tracked when they fell asleep and when they woke up. They also had blood taken for tests of cholesterol, triglyceride, and insulin levels, all of which can contribute to risks of heart disease and diabetes.
Almost 85% of the participants went to sleep and woke up later on their days off than they did during the workweek. The researchers found that the greater the mismatch between the time they slept on weekdays and weekends, the higher their metabolic risk was. Sleeping late on days off was linked to lower HDL (good) cholesterol, higher triglycerides, higher insulin resistance, and higher body mass index. The associations persisted after controlling for physical activity, how many calories they ate, alcohol use and other factors.
"Our findings suggest that a misalignment of sleep timing is associated with metabolic risk factors that predispose to diabetes and atherosclerotic cardiovascular disease," the study concluded.
It appears that changing sleep patterns on weekends can put a person out of sync with your internal clock, which in turn may affect factors that increase the likelihood of diabetes and heart disease. However, the study was small and of a short duration.
The study was published in the Journal of Clinical Endocrinology and Metabolism.