In this report, we describe physical activity levels worldwide with data for adults (15 years or older) from 122 countries and for adolescents (1315-years-old) from 105 countries. Worldwide, 31·1% (95% CI 30·931·2) of adults are physically inactive, with proportions ranging from 17·0% (16·817·2) in southeast Asia to about 43% in the Americas and the eastern Mediterranean. Inactivity rises with age, is higher in women than in men, and is increased in high-income countries. The proportion of 1315-year-olds doing fewer than 60 min of physical activity of moderate to vigorous intensity per day is 80·3% (80·180·5); boys are more active than are girls.