The health guidance for metabolic syndrome checkup also says that we should try to do light exercise such as walking, walking in water or bicycling on a regular basis. It is said that exercise is a good way to maintain good health, but what is the mechanism behind this?

When we exercise, we use our muscles. In fact, when we do so, the muscle cells release substances that cause oxidative stress.

When you exercise, your heart rate speeds up and your breathing increases, your body consumes more oxygen than when you are not exercising.

The increased consumption of oxygen means that reactive oxygen species (ROS) are also generated. Since active oxygen is a causative agent of oxidative stress, exercise increases oxidative stress in the body.

However, on the other hand, the body’s ability to counteract oxidative stress also increases.

In other words, regular moderate exercise regularly raises oxidative stress and at the same time increases the body’s ability to counteract oxidative stress.

So, is moderate exercise meaningless?

In fact, when comparing the life expectancy of people who exercise regularly and those who do not exercise at all, the life expectancy of those who exercise is longer. Sports medicine doctors say that oxidative stress has a lot to do with this result. In other words, moderate exercise has a positive effect on oxidative stress.

That being said, more muscle mass is not always better.

Some people think that exercise is the way to keep their body in shape, but what kind of body shape do you think is healthy and long-lived?　

You may think that a muscular, so-called macho body is strong and healthy, but in fact, there is not much relationship between longevity and muscle mass.

Of course, it is better to have a certain amount of muscle mass, but it is enough to be able to live your daily life with ease.

So, what is a healthy body type that is suitable for a long life?

You may have heard the term “BMI” before.

BMI is calculated by dividing weight [kg] by (height [m] x height [m]).

According to the guidelines of the Ministry of Health, Labor and Welfare, a BMI between 18.5 and 25.0 is considered to be “normal weight”. Is it true that people with a body type that fits this normal weight category live longer?

Actually, it is not so easy to say. You may want to be a little thinner than normal weight. However, the body type that is said to live the longest is the opposite; it is a slightly flabby body type that is between 24.0 and 26.0 on the BMI scale, which is the upper limit of normal weight.

You may be thinking, “If muscle mass is not important for longevity, and a slightly flabby body shape is better, then I shouldn’t be exercising, which raises oxidative stress”. 

As mentioned above, if you don’t exercise, your oxidative stress will certainly not increase. However, the ability to counteract oxidative stress is also not improved, and as a result, it is not good for the body.

On the other hand, too much exercise also increases oxidative stress in the body, exceeding the body’s natural ability to counteract oxidative stress.

Exercise that is too strenuous is also bad for the body because it exposes the body to too much oxidative stress.

The best way to live longer is to maintain a good amount of muscle mass and increase your ability to counteract oxidative stress by exercising regularly with a moderate exercise load.