Getting fit in middle age boosts your chances of a longer life

A new study published in the BMJ suggests that becoming more active during middle and older age is associated with a lower risk of death, regardless of past activity levels or existing health conditions.

It shows that meeting and maintaining at least the minimum public health recommendations (150 minutes per week of moderate physical activity, according to the NHS) could prevent up to almost half of deaths associated with inactivity.

Researchers from the University of Cambridge analysed how long-term changes in physical activity are associated with dying of heart disease and certain cancers.

They used data from over 14,000 men and women aged 40-79, who were recruited between 1993-1997. Participants were assessed at the start of the study and then a further three times over an average of 7.6 years up to 2004. Mortality was then assessed up to 2016.

Physical activity markers included activity at work (eg, sedentary office work, standing work, physical and heavy manual work) and leisure-time activity, such as cycling, sports, and recreational activities.

The benefits were greatest for those with existing high levels of physical activity who became even more active over time, with a 42% lower risk of early death.

Speaking to ABC News, co-author of the study Dr Soren Brage said that boosting your exercise levels is like "putting money in a bank".

Brage has maintained however that if you're in your early 20s you shouldn't wait until you're older to start exercising. It's something you should be doing now.

"Once you get to 70 you're going to be going downhill, whatever you do. But if you start higher up the hill it'll take you a lot longer to reach the bottom."

This study was published in the BMJ.