Physical activity, sleep and obesity

Observational studies have suggested associations between sedentary lifestyle, physical activity, sleep duration and obesity. In this study, researchers used two-sample Mendelian randomization analyses to look for causal links between sedentariness, physical activity, sleep duration and obesity. Different leisure screen times appeared to be causally linked with obesity risk. On the other hand, obesity was not causally linked with the use of screens for work, physical activity or sleep duration. The causal relationships revealed could involve the pathways of cortisol synthesis, thyroid hormones and insulin secretion.