When we exercise, especially strength training, it does increase the content of testosterone, especially testosterone in hair follicles, which will react with an enzyme and become a hormone, which will increase the secretion of sebum. The more this hormone, the more sebum, which is more likely to cause pore blockage. Sweat itself does not cause acne, but because clothes absorb sweat and are wet after sweating, the skin remains moist all the time. As we all know, dry and ventilated places are not easy to get moldy, and dark and humid places are more likely to get moldy. Similarly, some molds in the body also like humidity. Some substances in moisture and sweat will make these molds multiply in the pores, causing skin infections, and then the pores will swell and produce acne. This phenomenon is very common in gyms. Solution: Keep your skin dry during exercise, wipe off the sweat on your face and body in time, pay attention to using your own clean towel, infiltrate the air-dried clothes, take a shower immediately after exercise and put on clean clothes. This can largely avoid problems.