Pain for all ages Uwe Krejci/Getty

HIIT it! We’re often told that exercise is the best medicine, and it now seems that regular high intensity interval training (HIIT), in particular, is great for reversing the declining ability of our cells to generate energy.

HIIT involves short bursts of very intense activity, interspersed with recovery periods of lower-intensity exercise. Sreekumaran Nair at the Mayo Clinic in Rochester, Minnesota, and his colleagues assigned groups of people aged between 18 and 30 and between 65 and 80 to three months of interval training, weight training or a combination of the two. Muscle biopsies were taken before and afterwards to measure the impact of these regimes on their cells.

Interval training boosted the ability of the mitochondria within cells to generate energy by 69 per cent in older volunteers, and by 49 per cent in the younger group.


Mitochondrial activity declines with age, which may aggravate fatigue and reduce the size and ability of muscles to burn excess blood sugar – a risk factor for diabetes. But this decline was halted and even reversed in the older interval-training group. “After three months of interval training, everything converged towards what we saw in young people,” says Nair.

Interval trainers also saw surges in lung, heart and circulation health. The amount of oxygen they could inhale and consume at full tilt rose by 28 per cent in the younger group and by 17 per cent in the older group. There was no corresponding change among weight trainers, although combination training boosted oxygen consumption by 21 per cent among older exercisers.

Nair says the greatest benefit from weight training was the addition of new muscle mass, but it triggered none of the mitochondrial and respiratory benefits. The combination regime generally produced intermediate results.

Journal reference: Cell Metabolism, DOI: 10.1016/j.cmet.2017.02.009

This article will appear in print under the headline “Interval training rejuvenates ageing cells”

Read more: Exercise may be the best anti-ageing pill