Doc of the Week: The Truth About Exercise Doc of the Week

Doc of the Week: The Truth About Exercise

Like most people Michael Mosley would like to be fitter and healthier, but he doesn’t want to spend hours in the gym. Well, the good news is that he may not have to as new research suggests that some people can get significant benefits from just three minutes of high intensity exercise a week. http://1, Mon, Sep 26th 20.30.

Mosley explodes a few of the more popular myths around exercise in this BBC-made documentary. He discovers the hidden power of simple activities such as walking and fidgeting and finds out why some of us don't respond to exercise at all. Hallelujah, I hear you say!

He explains how exercise can ensure that we live longer and healthier lives. That’s something we probably all knew – but here’s the big surprise - a few relatively short bursts of intense exercise can deliver similar health benefits to several hours of conventional exercise. It all depends on your genes as new research suggests that, for some people at least, just a few minutes a week is all they require to stay fit and healthy.


They call it high intensity training, or HIT for short, and there is a significant body of research espousing its benefits, according to Mosley. He decides to try it for himself under the guidance of Jamie Timmons, professor of ageing biology at Birmingham University, who assures him that just three minutes of HIT a week for four weeks would result in significant changes to certain important health indices, including insulin sensitivity and aerobic fitness. It’s not for everyone though, and those with any existing medical issues should consult a doctor before embarking on this type of programme, he warns.

Mosely was keen to find out more as his father had been diabetic and had died from complications related to the disease. Insulin removes sugar from the blood. If this process fails, the person in question is likely to become diabetic. However, studies had shown that three minutes of HIT a week could raise insulin sensitivity by as much as 24% and, naturally, Mosley was more than a little curious to see if it would work for him.

He was also interested to see if he would derive any benefits to his aerobic fitness. This is the measure of how good a person’s heart and lungs are at getting oxygen into the body. According to Timmons, aerobic fitness is a key indicator of future health.


However, not everyone will get the same benefits from HIT. People respond to exercise in different ways. Indeed, some people will get no benefit from it whatsoever. It’s all about genetics. Mosley quotes one particular study here where, of 1,000 people tested, 15% (super-responders) saw huge improvements to their health from four hours of exercise per week, whereas 20% (non-responders) showed no real benefits at all. He is tested but the results are kept from him until after he has completed his exercise programme.

When Mosley does start exercising, he is surprised at how simple it is. He gets on an exercise bike, warms up for a couple of minutes and then goes flat out for 20 seconds. After a couple of minutes to catch his breath, he goes flat out for another 20 seconds. He then continues to cycle gently for a few minutes, catching his breath once again, before going full pelt once again for a third and final 20 seconds.

It all sounds very simple. According to Timmons, what makes the difference is that this type of intense exercise actually uses far more of muscle tissue than classic aerobic exercise. It’s not just leg muscles, but shoulder and arm muscles too – up to 80% of the body’s muscles are engaged compared to between 20-40% for walking or moderate intensity jogging or cycling. HIT is better able to break down the body’s stores of glucose which are deposited in the muscles as glycogen. As this glycogen is broken down through exercise, it creates room for more to be sucked out of the blood and stored for later use.


Mosley completed his four weeks of HIT but, by his own admission, was somewhat sceptical as to what the results would be. He had completed just 12 minutes of intense exercise and 36 minutes of gentle pedalling over the four week period and wasn’t expecting much before he returned to the lab to be tested. The results were mixed – his insulin levels had dropped by a remarkable 24% as had been suggested in several studies, but there was no noticeable gain in his aerobic fitness at all. However, his disappointment was tempered when Timmons revealed that the genetic tests carried out before he started the regime indicated that he was a ‘non-responder’ and no amount of exercise would have benefitted him in this regard.

All in all, Mosley was pleased with the results of the experiment, particularly after finding out that the genetic signs suggested that he would gain very little from the experience. He intends continuing with HIT, but isn’t expecting to break the four-minute mile any time soon.

There are plenty of great documentaries to watch out for on the eir Sport pack every week. From football to golf, GAA, rugby, athletics and beyond, we’ve got something for everyone. Watch out next week for another fascinating behind-the-scenes glimpse into the sporting world or go to http://for more sports news and stories or http://to find out more about how we're setting sport free.

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