Age of Strength

Age of Strength
August 2, 2016

There are certain realities that come with aging. Bones and muscles weaken, the metabolism slows down and the heart’s capacity to pump blood decreases. 

Much of aging manifests in physical declines, but new research from Duke University and the North Carolina Research Campus in Kannapolis shows that these physical declines may begin at an earlier age than when medical professionals generally look for them.

The research, published in the Journals of Gerontology: Medical Sciences, shows that these declines begin to manifest in a person’s 50s, when many doctors begin looking for functional declines in a person’s 70s or 80s. 

WalkingThis finding comes out of Duke’s long-term study, Measurement to Understand the Reclassification of Disease of Cabarrus/Kannapolis (MURDOCK) Study, which tracks the health of 12,000 North Carolinians between 30 and 110 years old.

For this study, Duke Medicine professor Miriam Morey and her colleagues examined 775 MURDOCK participants as they completed physical function tests including repeatedly standing up and sitting down, standing on one leg and walking for six minutes.

As you might expect, participants in their 60s and 70s had less endurance for aerobic activity and slower walking speed. Both men and women in their 50s, however, were less able to stand on one leg or even stand up from a chair.

But these results are not inevitable, or they can at least be slowed, Morey says. Regular physical activity can help keep the heart, bones and muscles strong even as they naturally begin to weaken due to old age.

The American College of Sports Medicine recommends endurance training for 30-60 minutes daily for seniors (those who do not have any medical conditions that would make exercising unsafe) as well as strength training and flexibility exercises two days per week.

Staying idle and sedentary, on the other hand, speeds the decline of the body’s physical performance. In an extreme example, in 1966, five young, healthy volunteers agreed to three weeks of bed rest for a study, and predictably, their health suffered for it.

Thirty years later, those volunteers went back in for a check-in and the researchers in that study found that the three weeks they spent on the couch did more to deteriorate their bodies than the 30 years between the two studies. Granted, those thirty years covered the time between the volunteers’ early 20s and early 50s, but when muscles don’t get their normal workload, they do weaken. NASA astronauts have to spend hours every day working out while working in space to counteract the fact that those muscles no longer have to fight gravity every day and they use bed rest studies to mimic that effect on Earth.

This data could also be useful in a clinical setting, as tests such as standing from a sitting position or standing on one foot can easily be done in a doctor’s office at every wellness check.

Morey says that future research will focus on whether there are molecular markers in the blood that could show these changes happening, so scientists could learn more about the biochemistry of aging and doctors can track it with a blood test.

—Daniel Lane

Daniel Lane covers science, medicine, engineering and the environment in North Carolina.