The study: Twenty-five healthy men and women with an average age of 70 engaged in twice-weekly, one-hour resistance training for six months using standard gym equipment. In addition, 25 students from McMaster University with an average age of 26 participated. Before-and-after tissue samples were taken from the thigh muscle of each participant.
First, here's a lesson from Biology 101: Mitochondria act as the "powerhouse" of cells. Using the tissue samples, the researchers conducted gene expression profiles involving age-specific mitochondrial function. Multiple studies have suggested that mitochondrial dysfunction is involved in the loss of muscle mass and functional impairment commonly seen in older people. The study was the first to examine the gene expression profile, or the molecular "fingerprint," of aging in healthy disease-free humans.
The results: In the older adults, there was a decline in mitochondrial function with age; however, exercise resulted in a remarkable reversal of the genetic fingerprint back to levels similar to those seen in the younger adults. The study also measured muscle strength. Before exercise training, the older adults were 59 percent weaker than the younger adults, but after the training the strength of the older adults improved by about 50 percent, such that they were only 38 percent weaker than the young adults.
"We were very surprised by the results of the study," said study co-author and genetic scientist Simon Melov of the Buck Institute. "We expected to see gene expressions that stayed fairly steady in the older adults. The fact that their 'genetic fingerprints' so dramatically reversed course gives credence to the value of exercise, not only as a means of improving health, but of reversing the aging process itself, which is an additional incentive to exercise as you get older."
Dr. Mark Tarnopolsky of the McMaster University Medical Center, added, "This shows that it's never too late to start exercising and that you don't have to spend your life pumping iron in a gym to reap benefits."
The study findings were published in the online open access journal PLoS One.
--From the Editors at Netscape
