Seventy-five minutes of brisk walking a week is enough to extend life by almost two years.

London - Walking for just two and a half hours a week could add years to your life, researchers believe.

The study found even half of that is beneficial, with 75 minutes of brisk walking a week enough to extend life by almost two years.

The analysis of the lives of more than 600,000 men and women aged 40 and over also added weight to the idea that it is possible to be fat and fit.

The experts from the US government’s medical research agency and Harvard University crunched the results of six previous long-term studies into health and lifestyle.

Sapa-AFP reports that the analysis, published in PLOS Medicine, pooled self-reported data on physical activities and body mass indexes (BMIs) -a ratio of weight to height - from some 650,000 people aged 40 and older enrolled in one Swedish and five US studies.

The analysis focused on moderate exercise – defined as walking fast enough to break into a sweat but slow enough to hold a conversation.

The researchers used the studies to calculate the boost to life expectancy linked to specific levels of physical activity and found that brisk walking for up to 75 minutes per week was associated with a gain of 1.8 years in life expectancy.

“Being active - having a physical activity level at or above the World Health Organisation-recommended minimum of 150 minutes of brisk walking per week - was associated with an overall gain of life expectancy of 3.4 to 4.5 years,” the summary said.

Overall, the researchers concluded that less physical activity was linked with a shorter life expectancy no matter a person's body mass index.

The biggest gains were seen in people of a healthy weight, where two and a half hours of moderate exercise a week – as recommended by the Government – extended life by more than seven years, the journal PLoS Medicine reported.

However, people of a healthy weight who didn’t exercise could expect to die 3.1 years earlier than obese people who did stay active – a finding that underlines the importance of exercising whatever your weight.

Harvard professor Dr I-Min Lee, the study’s senior, said: “We must not underestimate how important physical activity is for health – even modest amounts can add years to your life.”

The benefits were clear, with two and a half hours of brisk walking a week adding 3.4 years to life on average. Doing twice this added 4.2 years, while walking for seven and a half hours weekly added 4.5 years to life. - Daily Mail