EXERCISE REVERSES SIGNS OF AGEING
medicalnewstoday.com
May 23, 2007

Original Link

Scientists in Canada suggest that twice weekly sessions of resistance exercise training using standard gym equipment can reverse the signs of ageing in the skeletal muscles of the over 65s.

You can read the full text of their article in the new Public Library of Science's international, peer-reviewed, open-access, online publication PLoS One <http://tinyurl.com/2s3jom>.

One of the signs of ageing is weakening of skeletal muscles and increasing dysfunction of their mitochondria.

Mitochondria are tiny energy units within every cell of the body. They have their own DNA code that 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.

Mitochondrial dysfunction is measured by counting the number of mistakes they make when they transcribe their DNA code to make essential materials like proteins. A "transcription profile" or "gene expression profile" is a measure of how well a person's mitochondria are working.

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 from 20 to 35 years, and the other group comprised 25 "old adults" over 65.

At the start of the study, they took skeletal muscle biopsies from both groups, from which they were able to assess their transcription profile. They also tested their muscle strength.

14 of the old adults then completed a 26-week whole body resistance exercise-training programme 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 sessions lasted one hour and took place twice a week.

Comparing the results before and after the exercise programme, Melov and his team found that the old adults improved their strength significantly compared to the young adults. Before the programme the old adults were 59 per cent weaker than the young adults. After the programme they were only 38 per cent weaker.

But the more remarkable result was the dramatic change in the transcription profile of the old adults.

Before the exercise programme the old adults had mitochondrial transcription profiles consistent with ageing, but after the programme, they became more like the transcription profiles of the young adults.

Both groups were comparable in all aspects of health and lifestyle, apart from age. They were healthy, were not on medication, and had similar diets. They did the same amount of physical activity every day, in that the researchers deliberately chose more sedentary young people and more active old people (relative to their own age groups), to emphasize the point that the study was about ageing and not about inactivity versus activity.

The detailed way in which the transcription profiles were compared is described in the study. It involved examining 596 different genes that before exercise training showed a "dramatic enrichment of genes associated with mitochondrial function with age". But after the training the "transcriptional signature of aging was markedly reversed back to that of younger levels for most genes that were affected by both age and exercise".

Melov and colleagues said that their results strongly supported the notion that mitochondrial dysfunction is linked to ageing in humans. But the exciting discovery is finding out that resistance training reverses many aspects of this.

They concluded that:

"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 six months of resistance exercise training."

They said that more research is needed to find out what the effects might be of long term or life long 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," they added.

.............

NHNE Aging & Anti-Aging Resource Page