Get out in the sun during the day; don't go all day without light

High value
Evidence B
Buys life
Disputed
Free
Takes minutes
No willpower

In plain words

Women who deliberately avoid the sun have a life expectancy 0.6 to 2.1 years shorter than those who get the most sun. Non-smokers who avoid the sun live about as long as smokers who get the most sun.

Cost: Free. A dozen or so minutes a day, on your commute and at lunch, is enough.
What you get: A Swedish study followed 29,500 (2.95万) women for 20 years. Compared with the group who got the most sun, those who deliberately avoided it had a life expectancy 0.6 to 2.1 years shorter. The authors wrote that “non-smokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group”
Notes: The dispute is that Sweden is at a high latitude with little sunshine, so the conclusion cannot be carried straight over to China. And people who avoid the sun may be frail or dislike going out to begin with. Also, don't get sunburned; still shade yourself from strong midday sun, because sun exposure raises the risk of skin cancer
Evidence grade: B : Supported by research but without a precise number, or based on small or single studies.
Sources: Lindqvist PG, Epstein E, Nielsen K, et al. (2016). Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort. Journal of Internal Medicine, 280(4), 375-387. https://doi.org/10.1111/joim.12496

Translated from the Chinese original. Original book, section 2, tip 31. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer