Taking a brisk 25-minute walk a day can add seven years to your life, scientists claim.

New research has found that regular exercise can reduce the risk of dying from a heart attack by half.

Even people who do not start exercising until they are in their 70s can still improve their health, the academics behind the study say.

Taking a brisk 25-minute walk a day can add seven years to your life, scientists claim (file picture)

Sanjay Sharma, professor of cardiac diseases at St George's University Hospitals NHS Foundation Trust in London, said gentle exercise can reduce the risk of dying from a heart attack in the average person's 50s and 60s by half.

'This study is very relevant. It suggests that when people exercise regularly they may be able to retard the process of ageing,' he said.

'We may never avoid becoming completely old, but we may delay the time we become old. We may look younger when we're 70 and may live into our 90s.

'Exercise buys you three to seven additional years of life. It is an anti-depressant, it improves cognitive function and there is now evidence that it may retard the onset of dementia.'

He said everyone should be doing at least between 20 and 25 minutes of walking a day, involving brisk walking or slow jogging.

'If you know that something is 20 minutes away, try and walk it if you've got time and not take the bus,' he added.

'People with a heart condition shouldn't run but walk to a point where they can still speak - but they shouldn't be able to sing. Following these simple directions is essential considering our sedentary lifestyles.'

He said exercise will bring benefits whatever age or condition.

New research has found that regular exercise, such as walking, can reduce the risk of dying from a heart attack by half

People who start exercising at the age of 70 are less likely to go on to develop atrialfibrillation, a heart rhythm condition that affects about 10 per cent of people over 80.

The research was carried out by a team at Saarland University in Germany, who introduced a group of non-exercising but otherwise healthy and non-smoking people to a programme of exercise.

It showed that aerobic exercise, high intensity interval training and strength training all have a positive impact on markers of ageing.

The authors found endurance exercise and high intensity exercise to be more efficient at achieving good health than just lifting weights, and is more likely to trigger the anti-ageing process.

Christi Deaton, professor at the Cambridge Institute of Public Health, said: 'The more active you are, and it doesn't matter when you start, the more benefit you are going to have.

'We recommend people who have cardiovascular disease or had myocardial infarction or heart failure to be physically active, because it's beneficial for them; so there's really no reason for healthy people not to exercise as well.

'The study brings a bit more understanding of why physical activity has that effect.