Older people with a purpose in life stay more physically fit

Older adults who have a strong sense of purpose in life may stay more physically fit than people who don’t believe their life has much meaning, a U.S. study suggests.

Researchers examined nationally representative survey data on how adults over age 50 thought about their purpose in life. Then, they followed participants over four years to see what happened to two indicators of physical fitness in the elderly: grip strength and walking speed.

People with an above-average sense of purpose in life were less likely to lose grip strength or walking speed during the follow-up period, and those with the highest sense of purpose were even somewhat likely to gain grip strength and improve walking speed.

“Purpose in life can be altered,” said lead study author Eric Kim of the Harvard T.H. Chan School of Public Health in Boston.

“The potential implication later down the road is that if we help people maintain a ‘reason to get up in the morning’ at a large scale, then we may be able to help more older adults stave off declines in physical functioning,” Kim said by email.

To see how purpose in life might relate to physical functioning at older ages, Kim and colleagues examined data collected in 2006 and 2010 as part of the Health and Retirement Survey. They had different groups of people in the analyses for grip strength and walking speed.

At the start of the study, people in the grip-strength group were 63 years old on average. Among the 4,486 with adequate grip strength at the start, 426, or about one in 10, developed weak grip strength by the end of the study.

In the walking speed group, participants were 71 years old, on average, at the beginning of the study. Among 1,461 with adequate walking function at the start, 687, or nearly half, developed slow walking speed by the end of the study.

Researchers also looked at data from psychological questionnaires to see how participants thought about their purpose in life. They calculated the average level of sense of purpose, and then looked at what happened for each incremental increase above the average.

Each one-increment, or standard deviation, increase in sense of purpose in life was associated with a 13 percent lower risk of developing weak grip strength and a 14 percent reduction in the odds of developing slow walking speed, researchers report in JAMA Psychiatry.

After researchers adjusted for participants’ health at the start of the study, symptoms of depression and health behaviors like exercise, smoking and drinking, however, only lower odds of reduced walking speed remained associated with an above-average sense of purpose in life.

They also found that among people with the strongest sense of purpose, grip strength was likely to increase, as was walking speed, but the walking-speed improvements were too small to rule out the possibility they were due to chance.

The study wasn’t a controlled experiment designed to prove whether or how a greater sense of purpose in life might make older adults stronger or fitter.

Even so, the results add to evidence suggesting that improving psychological wellbeing might also benefit physical health, Carol Ryff of the University of Wisconsin, Madison, writes in an accompanying editorial.

“Volunteering, learning new things, and cultivating relationships, hobbies and interests can be important avenues for increasing one’s sense of purpose in life,” said Patricia Boyle, a behavioral health researcher at Rush Alzheimer’s Disease Center in Chicago who wasn’t involved in the study.

“Purpose in life is robustly protective against many negative health and psychological outcomes,” Boyle said by email. “People of all ages can benefit from improving their sense of purpose.”