Young people worldwide are getting lazier and lazier.  

More than 80 percent of 11 to 17-year-old school-going boys and girls fail to participate in even one hour of physical activity each day, a suggested minimum requirement set by the World Health Organization (WHO) for staying healthy.

The situation is a lot worse for girls, who get much less exercise than boys, leading to calls for urgent policy intervention. Worldwide, only around 15 percent of girls and 22 percent of boys get sufficient physical exercise.

The findings are based on a survey of 1.6 million youths from 146 countries carried out between 2001-2016 for the first-ever global study of adolescent physical activity prepared by the WHO and published in the journal Lancet on Friday.

In 43 out of 146 countries, the number of boys meeting the minimum one-hour physical activity criteria was higher by at least 10 percentage points when compared with girls.

The highest gender gap exists in the U.S. and the Republic of Ireland, where the amount of boys doing at least one hour of exercise is 15 percentage points higher than their female classmates.

Inadequate physical exercise increases the risk of cardiovascular diseases, weak bones and triggers obesity at a young age. 

Surprisingly, Tonga, Samoa, Afghanistan and Zambia are the only countries where girls are more active than boys.

"Four in every five adolescents do not experience the enjoyment and social, physical, and mental health benefits of regular physical activity," said co-author Dr. Fiona Bull of the WHO.

If the trends found by the study continue, the global target of a 15 percent relative reduction in insufficient physical activity – a goal set by all countries at the World Health Assembly last year – would be challenging to achieve, warned the WHO.

The survey also shows boys are gradually increasing their physical activity in Bangladesh, India and the U.S. 

Over the surveyed 2001-2016 period, Bangladesh saw a 10 percent increase, Singapore 8 percent and the U.S. 7 percent in the number of boys becoming more active.

"Urgent policy action to increase physical activity is needed now, particularly to promote and retain girls' participation in physical activity," said study author Dr. Regina Guthold of the WHO.

While India and Bangladesh see a strong focus on sports like cricket, in the U.S., physical education in schools, extensive media coverage of games and good availability of sports clubs have motivated youths to indulge in more physical activity.

"The study highlights that young people have the right to play and should be provided with the opportunities to realize their right to physical and mental health and wellbeing," said Bull.

On the contrary, girls have been mostly consistent with a minor decline worldwide in their physical activity. The change ranges from a 2-percentage-point decline in Singapore from 85 percent to 83 percent, to a 1-percentage-point increase in Afghanistan.

The researchers found that girls in Bangladesh and India have the lowest levels of physical activity due to societal factors, such as increased domestic chores at home for girls.

Strong political will and action can address the issue, Bull added.