May 23, 2007

Among people aged 65 and older weekly workouts built on resistance exercise training that uses regular gym equipment can reverse ageing signs in skeletal muscles, according to the results of  a study conducted by Canadian scientists and published in PLos One.

A physiological indicator of ageing is the weakening of skeletal muscles and increasing dysfunction of mytochondria.

The DNA code in mytochondria is separate from the DNA in the cell’s nucleus, and they control a number of cellular processes such as energy supply. As muscles get older and weaker, the mitchondria inside their cells show increasing evidence of dysfunction.

A research team led by Dr Simon Melov from McMaster University Medical Centre in Hamilton, Ontario, took two groups of male and female volunteers. One group, comprised 26 "young adults" aged 20 to 35 years, and the other group comprised 25 "old adults" aged 65 and older.

As the study began, skeletal muscle biopsies were taken from both groups, from which researchers assessed their transcription profile. They also tested muscle strength among the volunteers.

Fourteen of the old adults then completed a 26-week whole body resistance exercise-training program based on stretching and weight-bearing exercise on gym equipment that involved 3 sets of 10 repetitions for each muscle group, including for instance leg press, chest press, leg extension, leg flexion, shoulder press, and lat pull-down. The twice-weekly sessions lasted one hour each.

Comparing the results before and after the exercise program, Melov and his team found the older adults improved their strength significantly compared to the younger adults. Before the program the older participants were 59% weaker than the younger subjects. After the program they were only 38% weaker.

Based on the full body of research the study concluded: "Healthy older adults show evidence of mitochondrial impairment and muscle weakness, but that this can be partially reversed at the phenotypic level, and substantially reversed at the transcriptome level, following 6 months of resistance exercise training."

They said that more research is needed to find out what the effects might be of long term or lifelong exercise in humans.

Melov and his team also suggest this research could open the door to using gene expression profiling to "screen for a variety of interventions that could reverse or return the aging signature towards that of younger adults".

"Candidate therapies or molecules that show promise could be entered into prospective trials to evaluate the efficacy in modulating the aging rate in skeletal muscle in otherwise physiologically normal adults," the researchers added.

Read the entire report: "Resistance Exercise Reverses Aging in Human Skeletal Muscle." Simon Melov, Mark A. Tarnopolsky, Kenneth Beckman, Krysta Felkey, and Alan Hubbard. PLoS ONE 2(5): e465. doi:10.1371/journal.pone.0000465