Media release

From: PNAS

Sleep duration and health outcomes across countries

On average, national sleep durations do not predict health in a universal manner, a study suggests. Humans need enough sleep to stay healthy, but the average sleep duration varies across countries. How national average sleep durations relate to health outcomes is unclear. Steven Heine and colleagues examined national-level measures of health and analyzed results from 14 studies spanning 71 countries to estimate average national sleep durations. The authors also analyzed online survey results from 4,933 adult participants in 20 countries. On average, people living in countries associated with relatively short sleep durations did not have shorter life expectancies or higher rates of heart disease or diabetes but had lower rates of obesity, compared with individuals in countries associated with relatively long sleep durations. People living in countries associated with relatively long sleep durations did not have better health outcomes than people in countries associated with relatively short sleep durations. In addition, the amount of sleep that healthy people reported was different across countries, and people who slept close to their cultural ideals tended to have better health. According to the authors, the findings suggest that people have flexible needs for sleep duration and that the duration of sleep necessary to satisfy basic physiological needs is achieved differently across countries.