'Fast exercise' even more powerful than thought, expert says

Can exercising for just 60 seconds a week transform your health? The BBC's Dr Michael Mosley says 'fast exercise' is even more powerful than experts thought

THE men in my family are not long-lived. My grandfather died in his early 60s (though the fact that he was a Japanese prisoner in Burma during World War II can't have helped), while my father passed away at the relatively early age of 74.

When he died, he was on a dozen medicines and suffering from a range of diseases, including type 2 diabetes, heart failure, prostrate cancer and what I suspect was early dementia.

At his funeral, a number of his friends commented on how similar I am to him. This was both flattering and disturbing, because I fear, along with his prominent nose, that I've inherited many of his more unhealthy tendencies.

But I also believe that although genes play a significant role in how well we age, lifestyle is just as important.

Down the centuries there have been lots of anti-ageing therapies, from injecting monkey glands to mega-doses of vitamins. But only a few things have consistently been shown to influence how well we age.

These include not smoking, moderate drinking, eating a diet rich in fruit and vegetables, doing exercise and keeping your weight down.

I've never been a smoker or a heavy drinker and I like fruit and vegetables, so that's not a challenge. But when it comes to doing more exercise and staying slim, well, that has been far trickier.

I found the standard advice – eat less and be more active – largely ineffectual. I kept trying and failing.

Then, a couple of years ago, I began looking into a radically different approach to exercise called High Intensity Training (HIT). The idea is that instead of trying to shed weight and get healthier by jogging for hours, you can get many of the more important benefits of exercise from as little as three minutes of HIT a week.

Everyone agrees that getting more active will add years to your life (around 2.2 years, to be exact).

But, more importantly, it will significantly reduce your risk of developing a range of chronic diseases, from cancer to heart failure, dementia to diabetes.

Exercise will also help you sleep better, improve your mood and even perk up your sex life, according to the well-regarded Mayo clinic in the U.S.

But how much should you do? In 2008, a committee of U.S. scientists recommended 150 minutes of moderate exercise a week, while cautioning the necessary amounts 'cannot yet be identified with a high degree of precision'.

'In trials, most people say they prefer HIT to conventional exercise, not least because it is over so quickly.' These 150 minutes a week remains the recommended level despite the fact that less than 20 per cent of us do anything like that. The most common excuse is a lack of time. That has certainly been mine – which is why the idea of HIT appeals to me.

Roger Bannister was a 'fast' exerciser

The principles behind HIT are not new. In Fifties Britain, a young medical student called Roger Bannister was determined to become the first person in the world to run a sub-four-minute mile.

He didn't have lots of spare time for training so he would go down to the track and do interval sprints.

These consisted of running flat out for one minute, then jogging for two or three minutes before doing another one-minute sprint.

He would repeat this cycle ten times, and then head back to work. The whole thing normally took less than 35 minutes.

In May 1954 he became the first person in the world to break the four-minute mile. Since then almost every middle-distance runner has done interval sprints as part of their training.

Jamie Timmons, Professor of Systems Biology at Loughborough University, has spent many years researching the benefits of what has come to be known as HIT in normal people.

He assured me that three minutes of HIT a week have been shown to improve the body's ability to cope with sugar surges (i.e., your metabolic fitness), and how good the heart and lungs are at getting oxygen into the body (your aerobic fitness).

Just three sessions of HIT a week for four weeks (12 minutes of intense exercise in total made a difference).

You'll want to eat fewer calories

Intrigued, I had blood tests taken and went through some baseline tests to assess my starting point fitness-wise. Then I began to do HIT.

I got on an exercise bike, warmed up by doing gentle cycling for a couple of minutes, then started to pick up the pace.

At the same time, I increased the resistance on the bike by setting it to the hardest level and then went flat out for 20 seconds.

I cycled gently for a couple more minutes to catch my breath, then did another 20 seconds at full throttle.

Another couple of minutes' gentle cycling, then a final 20 seconds going hell for leather and that was it. In no more than seven minutes my exercise for the day was complete.

I did three sessions of HIT a week for four weeks (12 minutes of intense exercise in total) and then went back to the lab to be retested.

The first surprise was the effect it had on my insulin sensitivity. This is a measure of the amount of insulin your body has to produce in response to a sugar surge to get that blood sugar back down to normal.

The less your body has to produce, the better. After 12 minutes of intense exercise, my insulin sensitivity had improved by a remarkable 24 per cent, something you would be unlikely to see after many hours of conventional exercise.

But although I was able to cycle longer and harder, I didn't see the 10  per cent improvement in aerobic fitness that typically happens when people do this regime.

Why not? Well, it turns out that when it comes to aerobic fitness, I can blame my parents.

I've had a genetic test, which reveals that, like 20 per cent of the population, I am a so-called  'non-responder' when it comes to aerobic fitness. This means that however much exercise I do, in whatever form, I will never become incredibly fit.