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katiebarnes@leisuremedia.com research round-up
In a new study, Swedish scientists have discovered that just 20 minutes of exercise can help ‘turn on’ your DNA
cell-ing point C
hanging the genetic code you are born with might sound impossible, but a new study suggests otherwise.
Published in the March issue of Cell Metabolism*
, scientists from
the Karolinska Institute – a medical university in Sweden – have proven that exercise can alter a person’s DNA almost immediately. The alterations are not to the main
genetic code itself, but rather to the DNA molecules within the muscle cells.
cell study For the study, the researchers examined 14 healthy but sedentary men and women aged 24 to 26 years old. At the start of the programme, a slither
of muscle was taken from participants’ quadriceps for testing. Participants then undertook a 20-minute exercise session on a stationary bike at either 40 per cent (low intensity) or 80 per cent (high intensity) of their maximum aerobic capacity. Muscle biopsies were taken again immediately after the session, as well as three hours after that.
methyl groups
their presence causes chemical switches to turn our DNA ‘on’ or ‘off’, thereby activating, silencing or cranking up our genes and their actions. When people exercise, the DNA
M 52
molecules within the muscle cells gain or lose marks of methyl groups on certain DNA sequences. These changes occur in stretches of DNA that serve as landing sites for enzymes known as
ethyl groups attach themselves to our DNA, affecting the way in which our genes work –
‘transcription factors’, which in turn are involved in ‘turning on’ genes that are known to be important in muscles’ adaptation to exercise. The Karolinska Institute researchers
therefore liken transcription factors to keys that unlock our genes. With methyl groups fi rmly in place, transcription factor ‘keys’ are prevented from entering DNA ‘locks’. But when the methyl groups are removed, it allows the keys to turn the locks and boosts the muscles’ capacity to work.
Researchers found that exercise altered DNA molecules within muscle cells
results explained In the study, the DNA within skeletal muscle that was taken from people after a burst of exercise bore fewer methyl groups (see information box below) than
it did pre-exercise. The more rigorous the workout, the more these chemical marks changed. These changes – which take place
in stretches of DNA that are involved in ‘turning on’ genes important for muscles’ adaptation to exercise – appear to be early events in the genetic reprogramming of muscle for strength and, ultimately, in the structural and metabolic benefi ts of exercise. “Exercise is known to induce
changes in muscle, including increased metabolism of sugar and fat,” says lead researcher Juleen Zierath. “Our discovery is that the methylation change comes fi rst.” When the researchers made muscles
contract in lab dishes, they saw a similar loss of DNA methyl groups. Exposure of isolated muscle to caffeine had the same effect – but it would take 50–100 strong coffees to mimic the effect of exercise.
*Zierath, JR et al. Acute Exercise Remodels Promoter Methylation in Human Skeletal Muscle. Cell Metabolism 15, pp405-411, March 2012 Read Health Club Management online at
healthclubmanagement.co.uk/digital april 2012 © cybertrek 2012
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