Longitudinal studies are expensive (it takes a long time to get results) and tricky (as a lot of participants tend to disappear over the years) but they are worthwhile as they can help sift out causal factors and help scientists answer important questions like... Does being fat make you sleepier during the day? Can losing weight make you more productive? And does depression cause poor sleep?
Researchers at Penn State Sleep Laboratory followed 1395 individuals over 7,5 years to investigate how and why excessive daytime sleepiness (EDS) occurs and published their results last month.
Their paper published in the SLEEP journal is entitled: Natural History of Excessive Daytime Sleepiness: Role of Obesity, Weight Loss, Depression, and Sleep Propensity .
What this paper clearly shows is how obesity, gaining weight and developing depression led to increased EDS over time and furthermore how suffering from conditions such as diabetes, anemia and asthma/allergies put you at risk for poor night-time sleep and therefore EDS.
This cements what we already thought true: diseases of lifestyle wreck your quality of life and productivity and it doesn't take very long... less than 7 years! This deterioration does not diminish or even stabilise with time, but rather worsens. On the other side of the coin, lifestyle improvements such as exercise, better nutrition and weight-loss can reverse this and send EDS into remission.
Let's get our best lifestyle on. What's stopping you?