80% of teenagers globally are too inactive - and it could shorten their lives 

More than 80% of school-going adolescents worldwide are not getting enough regular exercise, the World Health Organization (WHO) found in the first survey of its kind.

The recommended amount for children aged 11-17 is “at least one hour of physical activity per day," the WHO says. But 85% of girls and 78% of boys are falling short of that goal.

Naturally, there are regional variations and cultural explanations for inactivity. However, there is one universal truth: young people who are too inactive today are at high risk of health problems tomorrow.

From poor bone density and osteoporosis, to obesity and cardiovascular illnesses, inactivity can cause numerous worrisome ailments in later life.

Obesity in particular has become one of the biggest health concerns in many parts of the world. It has almost tripled since 1975, and in 2016, the WHO classified 650 million people as obese. In total, 1.9 billion people are classified as overweight.

As well having an increased likelihood of obesity-related illness in adulthood, obese children can experience breathing difficulties, high blood pressure, insulin resistance and diabetes and even psychological problems.

While diet is a large part of the global obesity epidemic, regular exercise is one of the best ways to tackle it. “Urgent policy action to increase physical activity is needed now, particularly to promote and retain girls’ participation in physical activity,” says study author Dr. Regina Guthold.

The WHO report estimates how activity trends among young people have changed between 2001 and 2016. It was based solely on self-reported data, which the report’s authors acknowledge may be subject to bias, as well as in-country activity monitoring surveys.

However, as the first study of this kind, it provides a global benchmark and a series of indicators about activity levels.

Both boys and girls are less active, but Afghanistan, Samoa, Tonga and Zambia are the only countries where girls are more physically active than boys.

Globally, inactivity among boys fell slightly between 2001 and 2016, with the greatest reductions in insufficient activity in:

For girls, the changes have been extremely small – and not always positive. The biggest improvement was Singapore, which saw a slight drop (85% to 83%). At the other end of the scale, in Afghanistan, there was a slight increase in inactivity among girls (87% to 88%).

Overall, the lowest levels of inactivity were seen in Bangladesh and India, where the report’s authors conjectured that societal factors, such as domestic chores, may account for girls being more active.

Boys are least likely to be getting enough physical activity in the Philippines (93% with insufficient activity). South Korea had the highest inactivity levels among girls (97%). Bangladesh was the country with the highest sufficient physical activity rates among boys (63%) and girls (69%).

The US was one of the best performing developed nations, which the authors attributed to well-established programmes of physical education in schools and the availability of sports clubs offering things like ice hockey, (American) football, basketball and baseball.

With obesity and inactivity rates rising, many low- and middle-income countries are now facing a double burden of disease, the WHO warns – because the noncommunicable disease risk is being piled up on top of existing problems with infectious diseases and, in some cases, malnutrition.