The hazards of physical therapy devices are mainly manifested in two aspects: first, any physical therapy it may produce heat. Then the heat is too large, may constitute burns and burns on the surrounding muscles, soft tissue, skin. Second, physical therapy is radiation. Generally speaking, the amount of radiation is not very large, the impact on the surrounding tissues and organs will not be too great. But if each time you do physiotherapy for too long, each time you do physiotherapy intensity is too high, there is a course of treatment and the time between the course of treatment is too short, there is still harm to the body, especially to the glands, such as the thyroid gland, male testicles, female ovaries, these glands will have some harm. So for young, unmarried, infertile young people, there are strict limits on the time to do physical therapy, that is, not too much, not too often.