In 2012, in her early forties, Kim Chan ran her first half-marathon for her grandfather, whom she lost to Alzheimer’s disease in 1991. In 2013 she ran again, for the very same reason. “The disease affects so many people’s lives,” she says, “So I ran to find a cure. Hopefully I’ll be able to keep it up for many years.” Kim raised $1,500 for the second half-marathon, in her hometown of Huntington Beach, Calif.