Karolinska: Genes influence aerobic training success

Research lead

Researchers at the Karolinska Institute in Sweden working with an international team of scientists have found an explanation for why some people seem to be more responsive than others to regular endurance exercise, identifying 11 gene variants that are particularly important in the maximisation of the body’s aerobic capacity.

The results could have a bearing on the recommendations given by medical specialists for reducing the risk of cardiovascular disease, Type II diabetes and obesity.

The research was inspired by the link between health and the ability to take up and use oxygen, or aerobic fitness. The more blood the heart pumps around the body, the more oxygen can enter the muscles, and the lower the risk of disease and premature death. This is one of the reasons why health experts recommend brisk walks, jogging, swimming, cycling and other physical activities.

However, not all people have the same capacity to benefit from exercise.

To examine this phenomenon, the researchers compared results from two exercise studies from Europe with one from America. The 514 participants underwent a series of monitored cycling-based endurance programmes for 6 to 20 weeks to improve their fitness. In spite of the fact that the average improvement in all groups was around 15 per cent, one in five participants increased their maximal aerobic capacity by only five per cent or less, demonstrating an indisposition to respond to this kind of endurance exercise.

The scientists took muscle samples before and after the training period and were able to show the presence of a strong correlation between the activity of some 30 genes and a individual’s response to aerobic training. They also found that 11 gene variants (SNPs) coincide with the ability to benefit performance-wise from endurance training.

“It might one day be possible to customise prescriptions of physical exercise for optimal health effects,” says associate professor Carl Johan Sundberg at Karolinska Institutet, who led one of the three studies. “For some people weight training might be better, while others might benefit more from endurance exercise.” He adds that it is possible that those who not respond with a performance increase may have seen an improvement in blood pressure, blood lipids and glucose metabolism, but these parameters were not measured in this study.

“We can now take a biological sample and say whether a person is likely to increase his or her maximal aerobic capacity through aerobic training,” said James Timmons of the Royal Veterinary College in London, who led the study with Professor Claude Bouchard of the Pennington Biomedical Research Center in Louisiana. “This could help doctors prevent and treat, say, cardiovascular disease, by giving a patient tailored advice based on the knowledge they have of his or her personal genetic makeup.”

Around a dozen universities and research institutes from the US, Britain, Denmark, Canada and Sweden participated in the study.