Exercise for good health: how intense, how much, how often…

“Physical activity must be considered as a treatment in its own right”, revealed the High Authority for Health (HAS), in an opinion issued on September 6. Diabetes, obesity, cancer, depression, asthma, Parkinson’s, schizophrenia… the list of diseases concerned is long and further enriched by six new pathologies. It remains to convince the doctors: like the coaches, they are on the front line and have been able to prescribe adapted sports sessions since 2016. With a good margin of progress, recalls Guillaume Py, teacher at the Faculty of Sport of Montpellier.

Would you say that we have long been aware of the interest of sport for health?

On the scientific level, it’s been a long time, and science has succeeded in a lot of proof on the benefits of exercise in recent years, I remember the first Anglo-Saxon publications titled “Exercise is medicine”. But before it becomes part of everyday life, there is always a significant delay… Exercise can and should be prescribed much more widely, and that would avoid a lot of things. In hypertensives, against metabolic diseases… we have even shown the link between “physical exercise and cancer”, in terms of prevention, on strokes… we have all that. Today, science is going beyond that and beginning to accumulate cellular and molecular evidence.

That’s to say ?

We know exactly what happens when we do physical exercise: what are the molecules released by the muscle, in terms of hormones, which allow the organs to dialogue, which contributes to health.

Everything goes through the brain?

Not mandatory. What goes through the brain is “it’s good for me, I’ll practice.”


So with a certain assiduity, we overcome the “laziness” that nails us to the sofa?

No… depending on how we feel, and even depending on certain skin types, certain exercises, on the secretion of endorphins which are powerful analgesics which make it completely addictive. But this is the case for very few people. What matters is to feel good in your body and in your head and that in your head there is enough motivation to say “it’s good for me”. Of course, you have to find fun. If there is no pleasure, it does not work. We often see it in institutions. I come from the department of Professor Mercier, who specializes in metabolic diseases. The first week of rehabilitation and retraining in the service always goes well and the constants return to balance. But when they come back home, there is a significant disengagement. Three, four, six months later, they stopped, when they know full well that everything is going better in terms of health. It’s the nature of man: we smoke and drink when we know it’s not good…

“The speech of the doctors is not at all adapted”

And we are not all equal in the perception of the interest of sport…

So, isn’t it all cultural? But if we stick to physiology, for the same exercise, the same load, there are some who will respond more than others. But the answer still exists. And doing too much sport is not good either.

What is the correct gauge? The 10,000 steps, the “three times a week”…?

There are plenty of recommendations. I retain the “three times half an hour per week of moderate exercise”, it has been proven that it was enough to have improvements on the systemic level, on the tissues… In the long term, while having fun.

This is also where people should be challenged: what is moderate, intense exercise? The quantification is quite easy: we wear the Polar (Editor’s note: training watch) and we base ourselves on our heart rate. This is the easiest choice. We calculate the theoretical maximum frequency of beats per minute with the formula “220 minus age” and from this we define intensity zones.

Otherwise, if we don’t succeed, there is no health benefit?

No, not at all… that’s the maximum, which makes it possible to calculate the intensity of effort. And meet the objectives of a 20-minute exercise at 65% of this maximum, for example. It’s very easy today with a watch, or your phone, to be watched.

There, you are talking about someone who is guided, who has a coach.. how do you do when you are alone to do your little program?

We can do exactly the same thing with modern tools, but be careful, when there is no proven heart problem. We then say that when you can focus on intensity, you have to raise your heart to get closer to the maximum, because there is a “dose/response” effect, there are things that are even better when we are at high intensity. But if you stay there for two hours every day, it’s deleterious. For me for example, at the age of 50 in a few days, my maximum is 170.

Do you feel that healthy sport is prescribed enough?

No. The discourse of doctors is not at all adapted, withdrawn and often out of step with that of the physiotherapist. The medical profession has not been trained at all in sports practice. Apart from a few, they still underestimate the leverage of physical exercise. But there is good work being done in the “health sports” houses.

Do we still have a lot to learn about the benefits of sport?

On the biological aspects, we still have things to learn: why sport is interesting against cancer for example. But where it will develop a lot is mental health in the broad sense, we are still in its infancy: physical exercise to fight against depression, epileptic seizures…

Is there a sport more interesting than others for health?

What counts in the benefits of physical exercise is energy expenditure. One of the activities that has one of the best ratios in terms of energy expenditure in relation to time spent is running. At a speed that will depend on your heart rate. But there are people, including me, with my ruined back, who can’t run anymore. So, doing the exercise bike, swimming pool, rowing machine… There are two types of complementary activities: “cardio” and things less “cardio” but more related to strength.

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