Heart attack patients should be prescribed exercise to reduce their risk of death, researchers have said.

Patients who become more physically active in the year after a heart attack can significantly reduce their risk of death, a new study has found.

Experts examined data on heart attack patients in Sweden and found that those who increased their levels of physical activity halved their risk of dying over four years.

Much research has focused on exercise as a preventative measure for heart attacks but there have been few studies examining exercise levels after a patient has suffered a heart attack, according to the abstract of the study which was presented to a European Society of Cardiology congress, EuroPrevent 2018, in Slovenia.

Swedish researchers examined data on more than 22,000 patients aged between 18 and 74 who had a myocardial infarction - a heart attack - between 2005 and 2013.

Data was collected on the level of physical activity in patients in the weeks after their heart attack and then again a year later.

Patients were asked how many times they had exercised for 30 minutes or longer during the previous seven days and were subsequently classed as "constantly inactive", "reduced activity", "increased activity", or "constantly active".

After adjusting for various factors, they found that compared to patients who were constantly inactive, the risk of death was 37%, 51%, and 59% lower in patients in the categories of reduced activity, increased activity, or constantly active, respectively.

"It is well known that physically active people are less likely to have a heart attack and more likely to live longer," said lead author Orjan Ekblom, associate professor, Swedish School of Sport and Health Sciences, GIH, Stockholm, Sweden.

"However, we did not know the impact of exercise on people after a heart attack. Our study shows that patients can reduce their risk of death by becoming physically active after a heart attack.

"Exercising twice or more a week should be automatically advocated for heart attack patients in the same way that they receive advice to stop smoking, improve diet and reduce stress.

"Our study shows that this advice applies to all heart attack patients. Exercise reduced the risk of death in patients with large and small myocardial infarctions, and for smokers and non-smokers, for example."