Thirty-year Harvard health study finds that variety is the spice of life when it comes to exercise

People can help their chances of living longer by having a variety of exercise routines, a Harvard study says. Photo / NZ Herald

Scientists have revealed the secret to living longer.

Harvard experts believe the optimal way to extend life is adding more variety to exercise routines.

They tracked more than 111,000 people over more than 30 years, finding that those with the broadest mix of physical activity had an almost 20% lower risk of early death from all causes.

Walking was the single activity associated with the lowest risk of death – 17% lower for those who did the most walking compared with those who did the least.

Individually, tennis, squash and racquetball were found to cut risk by 15%, rowing by 14%, running or weight training by 13%, jogging by 11% and cycling by 4%. Climbing the stairs regularly was linked to a 10% lower risk.

Those whose lives involved a regular, varied mix of activity saw the best results, with a 19% lower risk of death in total.

Meanwhile, the risk of death from heart disease, cancer, respiratory disease and other causes was lowered by between 13% and 41%.

Range of physical activity types

Researchers said the findings supported the idea that “promoting engagement in a diverse range of physical activity types, alongside increasing total physical activity levels, may help reduce the risk of premature death”.

Their analysis included 111,373 people, including 70,725 women and 40,648 men.

During the monitoring period, 38,847 people died – 9901 from cardiovascular disease, 10,719 from cancer, and 3159 from respiratory disease.

Those taking part reported personal information, medical history and lifestyle choices every two years, as well as information on exercises such as walking, jogging, running, cycling, swimming, rowing, tennis and squash, from 1986 onwards.

People were also asked to track how many flights of stairs they climbed a day. Questions on lower intensity activities, such as yoga or mowing the grass, were added later.

Units called Metabolic Equivalent Tasks were used to measure exercise intensity, and the study found that the ideal weekly exercise regimen totalled 20 METs from at least three different activities.

Researchers gave each person a score for each physical activity, which measured how much energy was burned during exercise rather than at rest.

However, the lowered death risk levelled off after these scores reached a certain point – the equivalent to two hours running or five hours brisk walking weekly.

“Beyond these thresholds, the associations were no longer significant,” researchers said.

This suggests the presence of a “potential threshold for the beneficial effects of physical activity”, they added.

Researchers said the study was observational, so could not prove cause and effect, but concluded: “Overall, these data support the notion that long term engagement in multiple types of physical activity may help extend the lifespan”.

Participants with higher total physical activity levels were less likely to have risk factors, including smoking, high blood pressure and high cholesterol.

They were also likely to weigh less, eat more healthily, engage in a broader range of activity, and drink some alcohol, the study found.

The study was published in BMJ Medicine.

Sign up to Herald Premium Editor’s Picks, delivered straight to your inbox every Friday. Editor-in-Chief Murray Kirkness picks the week’s best features, interviews and investigations. Sign up for Herald Premium here.