If your retirement plans involve a Harley-Davidson, take note: Motorcyclists age 60 and older are three times more likely to be hospitalized after crashing than younger riders. Brown University researchers analyzed data on seven years’ worth of motorcycle crashes that required emergency medical care. They found that though riders between the ages of 20 and 39 had 14 times the number of accidents that riders over age 60 did, the older riders had two-and-a-half times the risk of being seriously hurt—sustaining far more fractures, dislocations, and internal-organ injuries, including brain damage, than their younger counterparts. The findings come as aging Baby Boomers change the demographics of motorcycling: One in four bikers was over 50 in 2003, compared with one in 10 in 1990. Researchers speculate that worsening vision, balance, and reaction times may make older riders less able to avoid dangerous collisions. “Your bones become more brittle, and you lose muscle mass as you get older,” study author Tracy L. Jackson tells The New York Times. “It could just be a matter of aging and the body being less durable.”