Today's Kids Can't Run as Fast as Parents Did Children getting slower, fatter by the year By Rob Quinn, Newser Staff Posted Nov 20, 2013 1:33 AM CST 24 comments Comments Boys participate in a 100-meter race during a World Athletics Day meet in Bangalore, India. (AP Photo/Aijaz Rahi, File) (Newser) – Today's children are the most sedentary generation in history and they would be easily trounced in a race with younger versions of their parents, a new study finds. Researchers—who looked at data involving millions of children in 20 countries over more than 40 years—found that today's young people run a mile around 90 seconds slower than their counterparts did 30 years ago, reports the BBC. Children are, on average, 15% less fit than their parents were, and the decline is seen for both boys and girls and for all ages between 9 and 17, the AP notes. Fitness has been dropping by around 5% a decade, the study found, and while the decline is slowly leveling off in Europe and North America, fitness is still going downhill fast in China and other parts of east Asia. Researchers say obesity and sedentary lifestyles are probably playing the biggest role in the fall in fitness—and they warn that unfit young people will be unhealthier later in life. Experts recommend that children over 6 get at least an hour of moderately vigorous activity throughout the day, but the World Health Organization estimates as many as 80% of the world's young people aren't getting the necessary exercise.