health reporter
Weight training can make old muscles new again – down to the genetic level – a study of seniors out of Hamilton's McMaster University suggests.
The study, published today, says resistance exercise for people 65 and older can actually reverse important aging effects on skeletal muscles, to the point where they work genetically like those found in people four decades younger.
"We see big improvements ... after weight training," said Dr. Mark Tarnopolsky, an associate professor at the McMaster University Medical Centre.
"Many people were reporting they could pick up their grandkids, they could carry more groceries, it was easier to go up the stairs," said Tarnopolsky, an expert on muscle diseases and one of the paper's two lead authors.
The findings come as no surprise to life-long weightlifter David Smith.
"I'm 70 now – 70 – but it's only an age," said the Bolton resident. "I probably feel as if I was in my 30s to be honest. The only time I freak out is when I have to put my age down on a piece of paper for an application."
Smith has been lifting weights since he was 16, and continued during a 35-year teaching career that saw him retire in 1994 as a principal in west Toronto.
A skin cancer scare proved the benefits of keeping in top physical condition, Smith said.
"The doctors figured the fact I was lifting weights for so long kept the immune system strong and helped the body to fight a recurrence and preventing it from spreading."
The study, which was supported by the U.S. National Institutes of Health, was published online in the Public Library of Science's journal PloS One.
The study looked at DNA expression in the muscle cells of 25 healthy seniors, who had undergone twice-weekly resistance training for six months.
It concentrated in particular on the cellular mitochondria, the "powerhouses" that fuel activity in cells. They are typically depleted in older people, with many of the genes that affect them turned on or off by age. This depletion resulted in a loss of muscle mass and many of the mobility restrictions often found in seniors.
But Tarnopolsky said the genetic "fingerprints" of the exercising seniors actually shifted from their age-altered state to one more closely resembling those found in young men and women in their mid 20s to 30s.
"We improved or reversed to a large extent the ... gene signature of aging," he said.
The reversal was accompanied by a 50 per cent improvement in strength among the seniors.
Starting out about 60 per cent weaker than their younger study counterparts – determined via knee extension capacity – the training seniors ended up 38 per cent weaker after a half year of training.
Tarnopolsky said weight lifting might remove some of the mitochondria damaged by age-related stresses, replacing them with genetically intact ones. As well, it may turn on genes, switched off by age, that offer muscle cells protection from damage.
The study seniors, who had an average age of 70, had no diseases that affected their mitochondrial function and had never participated in weight training before. (The younger comparison group had an average age of 26).
The seniors, who had similar diets and were not on medications, worked out on standard equipment and spent one hour, twice a week, on arm, leg and chest exercises. The workouts involved 30 repetitions at various weights and resistances.
Barbara Ford, 72, took part in the study and said it made a "tremendous difference" in her health and stamina. "As the months went by, we were able to do a lot more. I impressed my grandchildren. They said I had Popeye muscles," she said.
Dr. Howard Dombrower, director of rehabilitation at Toronto's Baycrest Geriatric Health Care System, said it's been well established that exercise benefits both the physical and mental wellbeing of seniors.
But Dombrower said he has typically recommended aerobic exercise like walking or biking for most of his patients and that the study may cause him to consider resistance training as well.
Tarnopolsky said the study shows it's never too late to reap benefits from exercising and that you needn't have spent a lifetime pumping iron to find significant health improvements in later years.
With files from Paul Moloney
http://www.thestar.com/article/216706
posted by Bill at 5:38 AM
0 Comments:
Post a Comment
<< Home