One in 10 early deaths could be prevented if everyone engaged in a small amount of daily exercise such as a brisk 11-minute walk, a large study said on Wednesday.

Physical activity is known to reduce the risk of heart disease, cancer and other leading causes of death, but exactly how much is needed to have an impact has been unclear.

So an international team of researchers pooled together the results of 196 previous studies which included more than 30 million people to create one of the largest reviews conducted on the subject.

They calculated that around one in six early deaths would have been prevented if everyone in the studies had at least 150 minutes a week of moderate-intensity physical activity, which is the level recommended by Britain's National Health Service.

But even half that amount — 75 minutes a week, or less than 11 minutes a day — could prevent one in 10 of those deaths, according to the meta-analysis published in the British Journal of Sports Medicine.

That included a 17% reduction of heart disease and a 7% fall in cancer.

For a person who engages in little to no physical activity, 11 minutes a day led to a 23% lower risk of early death.

Soren Brage, an expert on the epidemiology of physical activity at Britain's Cambridge University and a co-author of the study, told AFP that it was "exceptionally good news".

"All you need to do is find a little bit more than 10 minutes every day," he said.

"And you don't have to go to the gym to do these types of activities, it's part of daily life," he added.

He suggested people try getting off at an earlier bus stop on the way to work — or cycling home.

"It's very flexible," he said.

Because it takes years to assess how exercise affects the risk of such diseases, many of the studies were carried out more than a decade ago, Brage said.

This means that the activity reported by the study participants was likely less accurate than what can be achieved by newer technologies such as fitness trackers, Brage said, acknowledging this was a limitation of the study.

Cardiovascular diseases such as heart attack and stroke killed 17.9 million people globally in 2019, while cancer accounted for nearly 10 million deaths the following year, according to the World Health Organization.