A new study has shown that severely obese people can reduce the risk of atrial fibrillation with exercise.

Atrial fibrillation is an irregular and often rapid heart rate that can increase the risk of stroke, heart failure and other heart-related complications.

A study by the Norwegian University of Science and Technology (NUST) examined data from 43,602 men and women – of which around 1,500 had developed atrial fibrillation.

Obesity is a well-known risk factor for atrial fibrillation and the study showed that people with a BMI greater than 30 have a significantly higher risk than those under that number.

The new finding in the study was that the activity level of obese participants plays an important role.

"The risk of atrial fibrillation was lower the more physically active a person was and this turned out to be especially true for people with obesity," said Lars Elnan Garnvik from NUST's Cardiac Exercise Research Group, who led the research.

"People who reported that they didn't exercise at all had about double the risk of developing fibrillations when compared to those who were physically active whose body weight was normal.

"However, people who were obese but who exercised a lot limited the increase in risk to no more than approximately 50 per cent. This suggests that physical activity is good for limiting the increased risk of atrial fibrillation in obese people."

The study has just been published in the European Journal of Preventive Cardiology.