Instead of yet another video game, maybe you should consider giving your kids an activity tracker for the holidays. You could be gifting them extra years of a healthy life. According to a report presented at the American Heart Association’s Scientific Sessions 2013, children in the U.S. and around the world can’t run as long or as fast as previous generations. This is important because running is an indication of cardiovascular fitness, which could impact the health of their hearts down the road.

Based on an analysis of 50 studies on running fitness conducted between 1964 and 2010 involving 25 million children, researchers concluded that cardiovascular fitness has declined over the past 46 years. In the U.S., cardiovascular fitness fell an average of six percent per decade, between 1970 and 2000. In a one mile run, kids today are about a minute and a half slower than their peers 30 years ago.  Why the decline? Researchers say that 30-60% of the decline in endurance running may be due to excess body fat. The American Heart Association recommends that all kids engage in at least 60 minutes of exercise daily that engages big muscles — exercise like running, swimming or cycling. Not bad advice for adults either!