Exercising for just 13 minutes a day could extend life expectancy by three years, researchers have found.
The findings suggest people do not need to spend hours in the gym to see benefits to health.
Experts have long warned that people are put off physical activity by fear of lifting weights or investing hours in competitive sport.
But the new study - which gathered data from thousands of people around the world - shows just a quarter of an hour of activity a day could reap rewards.
Health insurance firm Vitality - which bases its business model on giving discounts to people who are healthier - examined exercise tracking data from 140,000 of its customers.
The company found that inactive people - those who previously did less than 30 minutes of activity a week - saw their life expectancy grow by three years if they exercised for 90 minutes a week over a 12-month period.
That is less than 13 minutes each day, the equivalent of a short jog or bike ride, or just pushing a lawn mower around a lawn.
Inactive people who increased their exercise levels to three hours a week - or 25 minutes a day - saw their life expectancy increase by four years.
And the company also found that those who already keep fit - by doing the 2.5 hours a week recommended by the NHS - boosted their life expectancy further by doing more exercise.
If these people added just half an hour of exercise a week or an extra four minutes a day, taking their weekly total to three hours, they would see their life expectancy increase by 1.7 years.
Lord Sebastian Coe, president of the International Association of Athletics Federations, responding to the findings last night, said: ‘Many people don’t realise just how much of an impact exercise can have on their overall health and wellbeing - not just to improve longevity, but also on our mental wellbeing and even productivity.
‘Adding 30 minutes exercise to your week can be easily broken down into a few minutes every day.’
The researchers came to the figures by assessing their members’ life expectancy with an overall health check, tracking their exercise for a year, and their calculating their life expectancy again.
A major study published in the British Medical Journal in March this year estimated inactivity is killing 70,000 people in the UK every year.
Experts warn Britain runs on a ‘sitting-based economy’ in which the vast majority of working adults spend their days bound to a desk.
Some 30 per cent of us spend at least six hours a day seated during the week.
But tellingly, at the weekend this figure goes up to 37 per cent, suggesting we are even lazier in our leisure time.
The NHS recommends people get at least 150 minutes of moderate activity - including gardening, swimming or cycling - or 75 minutes of vigorous activity such as running or playing sports every week.
But officials admit 39 per cent of English adults of all ages do not follow this advice.
Nick Read, programme managing director at Vitality - which is launching a new exercise campaign alongside Park Run today [must keep] said: ‘Fitting activity into our lives can be incredibly difficult, yet adding only an extra 20 per cent a week can have a massive impact on our health.
‘As the research shows, you don’t have to run a marathon to notice the benefits - simply going for a 30 minute walk can make a big difference to your life expectancy.’