Proper exercise can maintain the level of androgen in the body. It is wrong to say that fitness can increase androgen, not increase it, but maintain or restore it.
For example, a person's normal androgen is 800ng/DL. At this level, he is full of energy and has a good sexual desire. However, due to improper diet and lifestyle, such as overeating, stress, inactivity, drinking, etc., he is obese, with a big belly and poor constitution, so his androgen may drop to 400ng/DL, his energy is not as good as before, and his sexual desire also drops.
If he can start proper exercise, slowly recover to his previous physique and relieve stress, then his androgen may return to 800ng/DL. This is the so-called fitness can increase androgen.
However, many studies have shown that long-term heavy exercise training will reduce androgen in the body.
Therefore, fitness should be moderate. For example, arrange 2-3 times a week for about 30 minutes each time, and the weight should not be too heavy.