An inflammatory problem?
Jeremy D. Walston, a geriatrician and molecular biologist who co-directs the Biology of Healthy Aging Program at Johns Hopkins University School of Medicine, believes that frailty may in part be related to the body's inability to regulate its normal inflammatory response. His research has found that frail people suffer from a constant low-grade inflammatory state.
"When something attacks the body, it sends out a number of inflammatory signals to fight an infection or heal a wound,'' says Walston, who also is principal investigator for Hopkins' Older Americans Independence Center. "In frailty, these pathways get turned on, and they don't get turned off." Such chronic inflammation can lead to weakening of skeletal muscles and the immune system.
Frail people also are less able to process glucose properly, he says, and they secrete more cortisol, a hormone that over time, as with chronic inflammation, also can damage skeletal muscles and the immune system.
Scientists don't yet understand how these findings relate to the more predictable changes associated with aging, or whether they are a cause — or a consequence — of frailty.
Researchers also are studying the impact of moderate physical exercise in preventing the most powerful indicator of frailty: slow walking speed. An ongoing study of 1,600 people between the ages of 70 and 89 is comparing the effects of a moderate-intensity walking and weightlifting to a program of health education only. The exercise group walks for 30 minutes several times a week and uses ankle weights to improve lower body strength. The education group receives information on diet, managing medications and other health-related matters, but not about physical exercise.
A smaller, earlier phase of the study suggested that physical activity was key, with a 26 percent reduction in walking problems among those who worked out regularly.
"You don't have to go to an exercise program at the gym,'' Kaufman says. "Clean your house. Walk to the mailbox to get your mail, or work in your garden. The greatest common denominator of frailty is muscle loss and slowing of gait, and it's amazing what physical exercise can do.''
Walston agrees. "Growing old may be inevitable, but growing frail is not,'' he says.
Cimons is a former Washington-based health policy reporter for the Los Angeles Times.