How does physical activity affect our health?
Professor François Carré: “ We have almost the same genome as homo sapiens. It developed the ability to store fat because it could not find food every day, as well as very good endurance, to succeed in hunting. We are genetically programmed to move, we cannot do otherwise. We still have these genes in us, but we eat way too much in relation to our physical activity. Our genes are stimulated by our diet, which is why we store. But we no longer stimulate endurance genes because we spend our time sitting. When we are sedentary and/or inactive, fat cells release molecules that increase inflammation and oxidative stress and decrease immunity. However, all chronic diseases develop when inflammation and oxidative stress increase. During physical activity, it is the opposite. Our body releases proteins, myokines, which reduce inflammation and oxidative stress and increase immunity. Physical activity helps fight chronic low-grade inflammation that leads to chronic diseases. Today physical activity is recommended for virtually all chronic illnesses. With the highest level of recommendation. »
“Regenerate the brain”
What about cardiovascular diseases?
“Myokines act on the heart and blood vessels. They increase the capacity of vessels to dilate, facilitate blood circulation and thus reduce blood pressure. They reduce blood sugar levels and therefore the risk of diabetes as well as bad cholesterol. And moderate physical activity stabilizes atherosclerotic plaques. Physical activity has a direct effect on all cardiovascular risk factors. As for the treatment of chronic diseases, physical activity is recommended after a heart attack at the same level of evidence as beta-blockers! »
Physical activity also has a protective effect on mental health.
“During physical activity, the brain secretes dopamine, endorphin, serotonin and BDNF, a molecule that promotes neurogenesis and cerebral angiogenesis. We can therefore regenerate the brain through physical activity. This is why physical activity promotes learning and memory and is effective in Alzheimer's disease. »
What do you say to those who manage to do 3 hours of sport per week, but spread over only two weekly sessions?
“The lifespan of myokines is 36 to 48 hours. So you should not skip more than two days without exercise. Walking twice a week, even for 1.5 hours, is not enough. You need to walk every day to maintain the benefits of physical activity. I'm not talking about sports, I'm talking about physical activity: walking, climbing stairs, doing squats. »
“Break periods of sedentary lifestyle”
So, great athletes may not benefit from the benefits of physical activity?
” Quite. And above all, sedentary lifestyle – time spent sitting – is at work. These are the same risks as physical inactivity but they act independently of each other. Practicing sport does not cancel out the effects of a sedentary lifestyle. The worst, however, is to be inactive and sedentary because the effects then multiply. An athlete can be sedentary. This is why it is now recommended to reduce the time spent sitting and to break up periods of sedentary lifestyle. Every hour, you need to move the body for 1 to 2 minutes. A working person spends on average 12 hours sitting per day. For a person who does not work, it is 9 hours. It is enormous. »
Can practicing half an hour of physical activity reverse the consequences of a sedentary lifestyle?
” Unfortunately no. If you sit for 10 hours, you need to do around two hours to 2 hours 15 minutes of physical activity to counter the effects of a sedentary lifestyle. This is why reducing sitting time is essential. We get up, we move a little, we stretch… The simple fact of sitting 30 minutes less during the day and replacing this sitting time with 30 minutes of physical activity reduces the risk of getting sick and dying early by 15%. The chair kills and lies to us because it does not rest us. »
“As important as math or French”
You conducted a study which showed that children are in poor physical capacity.
“The children are in very poor health. In 2022 in France, an 11-year-old schoolboy is not capable of running as fast as an active 65-year-old man for one kilometer. In 1987, the French schoolboy ran at 11 km/hour. Today he runs at 9.5 km/hour, his physical capacity has dropped by around 20%. But we know that in 10 intense training sessions of 10 minutes, we make up 40% of the delay compared to 87. So we have the solutions. »
What do you expect from public authorities?
“Children should get one hour of physical activity a day. I expect the Ministry of National Education to get children moving again. Physical activity must be as important a subject as mathematics or French. We must make it truly compulsory to initiate physical or sporting activity during the first 30 minutes of school. Children would perform better in other subjects. I argue that the teachers would finish the program, the children would be better, learn faster and retain more easily. Children's brains are not ready to learn without physical activity. It's proven. »
Source : Interview with Pr. François Carré, cardiologist and sports doctor in Rennes
