Regular exercise 'changes your genes', study finds
Exercising regularly can change not just your waistline but the way your genes work.
A study focused on pairs of identical twins – who have the same genetic makeup – but with different exercise regimes.
Researchers said their findings could help to explain exercise's long-lasting effects on health.
The healthier twins had differences in their epigenomes, which influence gene expression, with epigenetic marks linked to lowered metabolic syndrome, a condition that can lead to heart disease, stroke and type 2 diabetes.
The study suggests that markers of metabolic disease are strongly influenced by how a person lives, as opposed to just their inherited genetics.
Read more: How to start getting fit as a beginner
Michael Skinner, Washington State University biologist and the study's corresponding author, wrote: "The findings provide a molecular mechanism for the link between physical activity and metabolic disease.
"Physical exercise is known to reduce the susceptibility to obesity, but now it looks like exercise through epigenetics is affecting a lot of cell types, many of them involved in metabolic disease."
The researchers collected cheek swabs of 70 pairs of identical twins who also participated in an exercise study through the Washington State Twin Registry.
They used fitness trackers to measure physical activity and the participants' waistlines and body mass indexes.
Many of the twin pairs were found to be discordant, meaning they differed from each other, on measures of physical activity, neighbourhood walkability and body mass index.
Read more: A 1988 warning about climate change was mostly right
Twins with a high level of physical activity, defined as more than 150 minutes a week of exercise, had epigenetic alterations in areas called DNA methylation regions that correlated with reduced body mass index and waist circumference.
Those regions are also associated with over 50 genes that have already been identified as specific to vigorous physical activity and metabolic risk factors.
Scientists have previously noted that the majority of identical twins develop different diseases as they get older even though they have the same genes.
Epigenetics may help explain the reason why, Skinner said.
"If genetics and DNA sequence were the only driver for biology, then essentially twins should have the same diseases. But they don't.
"So that means there has to be an environmental impact on the twins that is driving the development of disease."
Watch: Meet the 81-year-old bodybuilder who still competes