[img_inline align=”right” src=”http://padnws01.mcmaster.ca/images/Tarnopolsky-Feb.jpg” caption=”Dr. Mark Tarnopolsky, shown here taking a muscle biopsy with the help of PhD student Michaela Devries, is the co-author of a study that shows resistance training can reverse the aging process in muscle cells. Photo courtesy of FHS.”]A new study provides more evidence of how exercise can pump up your quality of life as you age, and even help reverse the aging process.

The study conducted under the auspices of the Buck Institute in California and McMaster University shows that resistance training can reverse aging in the muscle tissue of healthy senior citizens at the genetic expression level.

Tissue samples taken from study participants aged 70 and older before and after they underwent six months of twice-weekly resistance training were compared to similar tissue samples taken from healthy men and women aged 20 to 29.

Analysis of the gene expression profiles, or the molecular “fingerprint” of aging in healthy, disease-free humans, showed that exercise resulted in a reversal of the genetic fingerprint to levels similar to those seen in younger adults.

The study, led by Simon Melov of the Buck Institute and Dr. Mark Tarnopolsky, a professor of pediatrics and medicine at McMaster University, also found improvements in muscle strength among the senior participants.

The results of the study were published Tuesday in PLoS ONE, an international, peer-reviewed online journal of the Public Library of Science.

The 25 older participants had never participated in formal weight training. The younger participants had an average age of 22. All were recruited through McMaster.

“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,” said Tarnopolsky, who co-authored the published paper.

The study involved examining age-specific “mitochondrial function.” Mitochondria act as the powerhouse of cells, and multiple studies have suggested that mitochondrial dysfunction is involved in the loss of muscle mass and functional impairment commonly seen in older people. Results from this study confirmed there was a decline in mitochondrial function with age, but exercise resulted in a reversal of this decline in human skeletal muscle at the level of gene expression.

Muscle strength was also examined. Strength measurement samples taken before the resistance training began showed the older adults in the study were 59 per cent weaker than the younger study participants, but after the training, they were only 38 per cent weaker.

“We were very surprised by the results,” said Melov. “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.”

Tarnopolsky noted that four months after the completion of the study, a follow-up showed the older participants were maintaining the benefits they gained during the project, even though they were no longer doing exercise at a gym. Most continued to do resistance exercises at home, lifting soup cans or using elastic bands.

“They were still as strong; they still had the same muscle mass,” he said.