'Earth-shattering' study reveals the best exercise for anti-ageing
The secret to keeping your body youthful may be found in the way you move.
A new study has found that high-intensity interval training (HIIT) can essentially stop cellular ageing in its tracks and, in some cases, rejuvenate the cells that repair damage in the body.
For the study, researchers from the Mayo Clinic took 36 men and 36 women split into younger (aged between 18 and 30) and older (aged between 65 and 80) age groups.
The participants were then assigned a three-month programme of HIIT, strength training or a combination of the two.
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So, to understand the way exercise affects us at a molecular level, the researchers then took biopsies from the participants' thigh muscles and compared them with samples from sedentary volunteers.
The strength-training group predictably saw the greatest improvements in muscle mass, but the findings that have been described as "earth shattering" were at a cellular level in the HIIT group.
Mitochondria are the "powerhouses" of our cells, responsible for creating more than 90 per cent of the energy needed by the body to sustain life and support organ function. Their function typically declines with age.
However, in the HIIT group, the mitochondrial functioning improved by 69 per cent among the older participants, and by 49 per cent among the younger group.
As well as improving their insulin levels, heart and lung health, some in the high-intensity biking group also saw a reversal of the age-related decline in mitochondrial function and proteins needed for building muscle.
The research provided an explanation for the many health benefits of exercise said the lead senior author, Sreekumaran Nair.
"Based on everything we know, there's no substitute for these exercise programmes when it comes to delaying the ageing process," says Nair, of the study published in the journal Cell. "These things we are seeing cannot be done by any medicine."
He adds: "If people have to pick one exercise, I would recommend high-intensity interval training, but I think it would be more beneficial if they could do three to four days of interval training and then a couple days of strength training."
Emmanuel Stamatakis of the Charles Perkins Centre at the University of Sydney says it is a "fascinating piece of research".
"This not only sheds light on how high-intensity interval exercise works at the cellular level, but [also] on the potential of vigorous exertion in general," says Stamatakis, who was not involved with the research.
It also shows what is happening beneath the sweat that makes HIIT more beneficial to our bodies than other forms of exercise. Which aspect of HIIT is responsible for such dramatic changes, however, is still an unknown.
"Assuming that the key attribute of HIIT is the vigorous intensity that challenges the human physiology to make rapid adaptations, this research supports well what we saw recently in a large epidemiologic study where even one to two sessions per week of predominantly sport/ exercise of vigorous intensity were associated with substantial all-cause, CVD and cancer mortality benefits," Stamatakis explains.
"These benefits were comparable with meeting the physical activity recommendations by doing regular physical activity of mostly moderate intensity."
Now the question is whether HIIT is right for everyone. Given how few of us manage to meet the recommendations, Stamatakis remains unsure.
"There is a big debate as to whether HIIT is the way to go for better population health, but it is certain that it has a time and a place," he says. "Although not every physically inactive person would be willing or able to join a HITT program, this new piece of research highlights that in addition to public health messages like 'move as often as possible, a little is better than nothing', we need to also add 'aim to huff and puff sometimes'."
This might be as simple as taking the stairs whenever you can – both a form of incidental and HIIT exercise.
"For many people, stair climbing will involve bouts of high-intensity activity lasting one or more minutes, and if this is repeated regularly enough in everyday life it could potentially improve fitness and other aspects of cardiovascular and metabolic health quite rapidly," Stamatakis says.
And of course, it will keep us young.
"There are substantial basic science data to support the idea that exercise is critically important to prevent or delay ageing," says Nair, who plans to look at the effect of exercise on other tissues in the body. "There's no substitute for that."