‘Social jetlag’ linked to obesity-related disease
Being out of sync with your body clock may affect your metabolism, leading to obesity and disease. Credit: JD.
Just as travelling to a different time zone can make you feel more inclined to curl up in bed at midday than grab a bite for lunch, you can get ‘social jetlag’ from living slightly out of sync with your body clock on a weekly basis. While this may have less of an obvious effect than travel jetlag, in the long term it could harm our health. Research by Parsons et al., published in the International Journal of Obesity, suggests those with social jetlag run a higher risk of developing obesity-related diseases.
Social jetlag occurs when you have a mismatch between the times that you sleep during the working week and on your days off. Perhaps you prefer to lie in at the weekends, but during the week you have to get up early for work. This mismatch is thought that to set your circadian clock off kilter, which not only controls when you fall asleep and wake up, but also keeps your metabolism in check. And while most people recover from travel jetlag within a day or two, social jetlag can continue for a person’s entire life, so could have long-lasting effects on your health.
While the rise of obesity in the West is generally attributed to high calorie diets and a sedentary lifestyle, there is growing evidence that disruptions to our internal body clock such as those caused by social jetlag may also play a role. To investigate the effects of social jetlag on obesity and risk factors for associated diseases such as type 2 diabetes, Michael Parsons and Pat Nolan joined forces with researchers in London, the USA and New Zealand. They gave 815 New Zealanders who were part of the Dunedin Longitudinal Study a questionnaire to fill in to assess their sleeping habits.
When they were 38 years old, these participants underwent a series of tests to assess their BMI, fat mass and girth, as well as indicators of inflammation and diabetes, used to determine if they were obese and showed any signs of obesity-related disease. The researchers found a correlation between social jetlag and being obese with warning signs of related diseases. This could be due to many different factors – perhaps these people just have a greater tendency to eat a poor diet and do less exercise, or maybe social jetlag causes changes in the expression of genes that regulate our metabolism.
While more research is required to determine the underlying cause for this correlation, this research suggests that cutting down on social jetlag could help us stay healthy. This adds to growing evidence for a link between social jetlag and obesity, and particularly highlights how social jetlag could increase our risk of obesity-related diseases. Since these diseases include some of the biggest killers in the western world, cutting down on social jetlag and working in sync with our body clock could help us live a long and healthy life.