Improper Sunbathing Not Only Burns the Skin but Also Causes Cancer
Today a gastric cancer patient from Guangdong Province consulted me because, after sunbathing, his skin was sunburned and the pain had radiated to his axillary lymph nodes. He asked whether he had developed axillary lymph node metastasis or bone metastasis.
On close inquiry, it turned out that this patient had read some popular science online by certain "experts," who claimed that the human body needs sufficient yang qi to fight cancer and therefore should sunbathe more and exercise often in the sun. As a result, during this period he had followed that "expert's" advice and used natural sunbathing to supplement his yang qi. Whether his yang qi rose is unknown, but his skin was sunburned first, triggering an inflammatory response in the body and lymph node pain, and the patient panicked.
His situation is very common. Sunbathing as a fashion once swept Europe and America; on lawns and beaches in some Western countries, naked sunbathers were everywhere, and this trend has now spread worldwide. As a result, in recent years the number of malignant melanoma patients has skyrocketed and is becoming younger. The reason is none other than that the UVA and UVB bands in ultraviolet sunlight are very harmful to human skin and are the chief culprits of malignant melanoma.
Only African blacks around the world carry genes that resist UVA and UVB; Europeans, Americans, and we Asians all have poor immunity to UVA and UVB, so we are more prone to malignant melanoma than blacks. Malignant melanoma is a cancer with a very high and very rapid fatality rate. The incidence of malignant melanoma in China has shown an explosive surge in recent years, which is not unrelated to the prevalence of sunbathing.
Therefore improper sunbathing is not only useless but harmful. As long as many years ago abroad, a group of volunteers made up of malignant melanoma patients and medical staff went to public lawns and beaches to publicize the dangers of sunbathing, reminding people sunbathing there to apply sunscreen and minimize the time and intensity of sunlight exposure. Proper sunbathing is indeed beneficial to the human body, but excessive sunbathing is very harmful. Sunburn is the lowest-level of the harms of sunbathing; causing cancer is the most deadly harm of sunbathing.
So what kind of people need sunbathing, and what kind of sunbathing counts as moderate?
People living in cold regions, or whose houses are located in the northwest corner where the sun rarely reaches, can sunbathe moderately, especially in winter; the elderly, the weak, the sick, the disabled, and pregnant women need it even more. Moderate sun exposure can supplement the vitamin D the body needs, boost immunity, and reduce colds. Generally speaking, during the cold-prone seasons of early spring and autumn-winter, 15–30 minutes of sun per day is enough. In the hot summer, sun exposure should be avoided as much as possible; summer is also not a high-incidence season for influenza, so there is no need to worry about flu.
Residents of tropical regions should not sunbathe specially. The sunlight most people receive during normal outdoor activities in daily life is already enough to produce the vitamin D the body needs; there is no need to sunbathe specially. Frail elderly people should sunbathe moderately, because they do not spend enough time outdoors.
If we travel or work for long periods in the sun, it is best to apply sunscreen, or wear long-sleeved clothes and long trousers and put on a hat to avoid excessive sun exposure. Farmers have known this truth since ancient times, so when working the fields in summer, they all know to protect themselves from excessive sun exposure.
Some "experts'" remarks are too extreme. When patient friends listen to their baseless, offhand "popular science," they must be careful not to be led astray. By the way, TCM yin-yang theory is not used this way either; TCM cannot take the blame for this.