A new study into the exercise behaviours of identical twins shows that physical activity changes the way our genes behave — for the better.
Seventy pairs of identical twins were studied over seven years, and their physical attributes as well as their epigenomes (gene markers) were analysed.
The Washington State University study found that the more physically active siblings in each pair of twins had lower signs of metabolic disease, measured by waist size and body mass index.
The more active twins had epigenetic marks linked to lowered metabolic syndrome, a condition that can lead to heart disease, stroke and type 2 diabetes.
Since the identical twins have the same genetics, the study suggests that markers of metabolic disease are strongly influenced by how a person interacts with their environment.
“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,” said Michael Skinner, WSU biologist and the study’s corresponding author.
The twins also answered questions about their lifestyle and neighborhoods. Many pairs were found to be discordant on measures of physical activity and live in neighbourhoods with different levels of walkability.
The twin with the higher level of physical activity, defined as more than 150 minutes a week of exercise, had epigenetic alterations that correlated with reduced body mass index and waist circumference.
“If genetics and DNA sequence were the only driver for biology, then essentially twins should have the same diseases. But they don’t,” said Skinner. “So that means there has to be an environmental impact on the twins that is driving the development of disease."
The study was published in the journal Scientific Reports.