While much is currently made of excess body fat and body mass index (BMI), recent research suggests that overall body composition is a more important indicator of longevity. Specifically, the more muscle mass that older adults have, the less likely they are to die prematurely. While the research does not definitively establish a direct cause-and-effect relationship between muscle mass and survival, it does indicate that muscle mass seems to be an important predictor of death. With this in mind, older adults may want to exercise more and incorporate more muscle-strengthening exercises into their routines. If arthritis, obesity, or another limiting factor stands in the way of doing so, the physical therapist can help overcome any problems.