More than 80 percent of adolescents worldwide are not physically active, including 85 percent girls and 78 percent boys, putting their health at risk by not doing regular exercise and spending too much time on screen, according to a new study from World Health Organization (WHO).

The study, published in the journal The Lancet Child & Adolescent Health, based on data reported by 1.6 million 11 to 17-year-old students - found that across all 146 countries studied between 2001-2016, girls were less active than boys in all but four (Tonga, Samoa, Afghanistan, and Zambia).