Sunbathing through glass does not replenish calcium. Sunbathing does not directly replenish calcium, but through the sun’s medium-wave ultraviolet rays to promote the synthesis of skin vitamin D₃, which in turn promotes the absorption of calcium and phosphorus by the intestinal mucosa, increasing the concentration of blood calcium and phosphorus, which is conducive to the development of bones and the prevention of osteoporosis. Medium-wave ultraviolet penetration ability is weak, the glass can block 80% of the medium-wave ultraviolet, separated from the glass is not conducive to the synthesis of vitamin D₃, and therefore, also can not promote calcium absorption. It is recommended to sunbathe directly outdoors and do some outdoor exercise appropriately. Do not expose yourself to UV rays for a long period of time, such as 12:00 noon to 4:00 p.m., in order to avoid causing damage to the skin. Those who are allergic to ultraviolet rays are not recommended to sunbathe in order to avoid triggering allergic symptoms. After sunbathing, you should drink more water, eat more fruits and vegetables to inhibit the production of melanin and prevent sun spots. If the examination finds calcium deficiency, you should consult a doctor in time.