London, Aug 23 : A study in more than 15,000 people has found that physical fitness is linked with a lower likelihood of developing atrial fibrillation and stroke. Atrial fibrillation is the most common heart rhythm disorder, affecting more than 40 million people worldwide. Patients with the condition have a five-fold higher risk of stroke than their peers. 'This was a large study with an objective measurement of fitness and more than 11 years of follow up. The findings indicate that keeping fit may help prevent atrial fibrillation and stroke,' said study author Dr Shih-Hsien Sung of the National Yang Ming Chiao Tung University, Taipei, Taiwan. The new study, presented at ESC Congress 2023, examined whether fitness was related to the likelihood of developing atrial fibrillation. The study included 15,450 individuals without atrial fibrillation who were referred for a treadmill test between 2003 and 2012. The average age was 55 years and 59 per cent were men. Fitness was calculated according to the rate of energy expenditure the participants achieved, which was expressed in metabolic equivalents (METs). The researchers analysed the associations between fitness and atrial fibrillation, stroke and major adverse cardiovascular events (MACE). Participants were followed for new-onset atrial fibrillation, stroke, myocardial infarction and death. During a median of 137 months, 515 participants (3.3 per cent) developed atrial fibrillation. Each one MET increase on the treadmill test was associated with an 8 per cent lower risk of atrial fibrillation, 12 per cent lower risk of stroke and 14 per cent lower risk of MACE, the findings showed. /IANS