Participants in the Louisiana Marathon and the Louisiana Half Marathon run past the LSU Lakes on Dalrymple Drive in Baton Rouge, La., on Sunday, Jan. 19, 2020.

Why do some people benefit so much from exercise while others enjoy few health gains or even suffer harm? Does age matter when it comes to exercise’s health benefits? Are there “molecular signatures” — sets of genes, proteins and other variables — that reveal the answers?

Researchers at Pennington Biomedical Research Center plan to answer these and related questions with a new $2.5 million award from the National Institutes of Health’s National Institute on Aging.

“Exercising usually leads to many health benefits. For example, exercise can help offset the declines in cardiorespiratory fitness, physical functioning and cardiometabolic health that come with aging,” said Owen Carmichael, professor and director of biomedical imaging at Pennington. “This is at least partly because physical activity improves the performance of mitochondria, the power plants of the cell, in skeletal muscle. But the change in mitochondria can be extremely different from person to person, and the reasons for the variation remain unclear.”

The study will involve about 375 participants, and Pennington plans to begin recruiting volunteers in the spring. For updates, visit

The four-year study will compare mitochondria responses between younger and older adults who undergo exercise training. Carmichael said the goal is to identify molecular factors that promote or discourage a positive mitochondrial change.

The study, according to a news release, is expected shed light on several theories, including:

  • Exercise will not improve mitochondrial function for a certain portion of the population.
  • Age will not limit the mitochondrial response to exercise.
  • Aerobic training will provide more mitochondrial capacity improvements than resistance training, regardless of age.

John Kirwan, executive director of Pennington, said a better understanding of the biology behind the benefits of exercise will advance personalized medicine.

“In the long term, we believe the study’s findings will help physicians use each individual's unique biological characteristics to precisely tailor exercise training for that person," Kirwan said. "In effect, physicians will be able to prescribe an exercise regimen that maximizes the health benefits for each individual patient."