New Research Suggests
We all know that exercise is good for us. It boosts circulation
and tones the cardiovascular system. It builds strength, burns calories
and reduces depression. It improves insulin sensitivity in people
with diabetes. It may even help delay the onset of Alzheimer's disease.
But here's what you didn't know: it can partially reverse aging
at the cellular level.
Exercise Helps Reverse Aging
A study appearing this week in the online journal PLoS One looks
at the effects of six months of strength training in 25 elderly
volunteers aged 65 and older (average age: 70). The researchers
took small biopsies of thigh-muscle cells from the seniors before
and after the six-month period, then compared them with muscle
cells from 26 young volunteers (average age: 22). "To be honest,
we were expecting some indication that the exercise program improved
strength," says biologist Simon Melov, director of genomics at
the Buck Institute in Novato, Calif., and coauthor of the study.
What the scientists didn't expect was what they actually foundthat
after six months of resistance training, there were dramatic changes
at the genetic level. As Melov puts it, "The genetic fingerprint
[of the elderly participants] was reversed to that of younger
peoplenot entirely, but enough to say that their genetic profile
was more like that of young people than old people."
What kind of workout routine does it take
to produce these changes? The seniors went through a rigorous
exercise programan hourlong session of strength training twice
a week for six months, using the same types of machines found
in most gyms. At each session, they performed three sets of 10
contractions for each muscle group, similar to a standard workout
(albeit using lighter weights than most young people would use).
Trainers and kinesiologists were on hand throughout to make sure
the participants used the machines properly and did not injure
themselves. It helped that all the participants were in good shape
to start withable to go shopping, walk the dog, play golf or
swim. That was deliberate, according to Dr. Mark Tarnopolsky of
McMaster University in Canada, who headed up the clinical portion
of the trial. The researchers wanted to zero in on genetic changes
related to aging itself, not changes that might be due to cancer
or heart disease.
And how did the
genes change? At the beginning of the six-month period, Melov
found significant differences between older and younger participants
in the expression of 600 genes, indicating that these genes become
either more or less active with age. By the end of the six months,
exercise had changed the expression of a third of them. Admittedly
that leaves two thirds of the genes unchanged. "The others appear
to be related to aging, but not exercise," says Melov. But he
was struck by a common feature of the ones that did change. Overwhelmingly,
they are involved in the functioning of mitochondria, the powerhouses
of cells, which process nutrients into energy.
You might expect
that, as a result, the participants had more energyand that's
exactly what they reported. "Anecdotally, some reported that before
the training, they had a hard time picking up their grandchildren,"
says Tarnopolsky. "Afterward, they could pick them up." Others
reported that it became easier to carry heavy grocery bags or
run up the stairs. And objective measurements showed that their
strength improved by 50 percent. For Barbara Ford, 72, of Hamilton,
Ontario, the real thrill came when her grandchildren came to visit
and admired her new biceps. "They thought it was a scream I was
getting 'Popeye muscles'," she says. "When they saw this, they
message is clear. "It's never too late to start exercising," says
Tarnopolsky. You're only as old as your genes.