Lilian White, MD
Posted on May 26, 2025
Concerns about excessive sun exposure are well documented, but in recent years insufficient sun exposure (ultraviolet radiation) has emerged as a public health issue. Inadequate sun exposure has been associated with an increased incidence of some types of cancers, metabolic syndrome, hypertension, cardiovascular disease, asthma, autism spectrum disorder, autoimmune diseases (eg, multiple sclerosis, type 1 diabetes), and Alzheimer disease. Although these associations may not be causative, they highlight the potential benefits of moderate sunlight exposure (5-30 minutes per day).
Ultraviolet radiation comprises both ultraviolet A and B (UVA, UVB, respectively) radiation. UVB radiation drives vitamin D synthesis; however, it is also associated with sunburns and the development of some types of skin cancer. UVA radiation is also associated with the development of skin cancer and photoaging. Ultraviolet radiation is present all year long, but peaks during summer months. Shade can provide partial protection, but ultraviolet radiation penetrates cloud cover, underscoring the necessity of protection.
Benefits of moderate sunshine exposure include promoting the production of vitamin D, boosting immune health, reducing blood pressure, improving mood, and supporting a healthy circadian rhythm. However, excessive sunshine exposure Increases the risk of some skin cancers, photosensitive rashes, sunburn, eye damage, and skin aging. The USPSTF recommends counseling people 6 months to 24 years of age with fair skin types to minimize their ultraviolet radiation exposure to reduce their risk of skin cancer. For adults older than 24 years with fair skin types, the USPSTF recommends selective counseling due to a smaller net benefit. There is insufficient evidence to recommend screening for skin cancer.
Approximately 5-30 minutes per day of sunlight exposure is typically recommended, with more or less depending on a patient’s skin type and latitude. It is estimated that 10-15 minutes of sun exposure daily to the face, arms, and hands in the spring and summer is similar to a dose of 1000 IU of vitamin D.
It is recommended to avoid sunburns as much as possible to reduce the risk of ultraviolet radiation while gaining some of the benefits. Options for protection from ultraviolet radiation includes clothing, sunscreen, and sunglasses. Clothing, such as wide-brimmed hats, rash guards, pants, and long sleeves, are options to protect the skin from excessive ultraviolet radiation. Sunglasses can protect the eyes from ultraviolet radiation. Clothing is the primary recommended way to protect infants younger than 6 months from ultraviolet radiation; sunscreen is NOT recommended in large amounts because of the infant’s thinner and more permeable skin, increasing the risk of exposure to chemicals in sunscreens. A small amount of sunscreen applied to an infant’s exposed areas, such as face or hands, is usually acceptable.
Sunscreen is helpful to protect against excessive sun exposure; however, people often apply it inadequately or incorrectly. Sunscreen with sun protection factor (SPF) of 15 or higher is recommended, although SPF of 50 or higher may provide better protection against inadequate application. People may apply 1 fluid ounce (or approximately one shot glass full) of sunscreen to adequately cover the body of an average adult. The double-application method has also been shown to improve UV protection, particularly before intense sun exposure (e.g., a day at the beach). Sunscreen is applied 15 minutes before sun exposure and then reapplied 15-30 minutes later (either before or during exposure). An editorial in American Family Physician, Should Your Patients Avoid Sunscreen?, is available with additional information.
Patients may express some concerns regarding harmful chemicals in sunscreens. The Environmental Working Group’s sunscreen guide can help them make informed choices, such as mineral-based sunscreens. Additionally, the American Family Physician patient handout, Safe-Sun Guidelines, is a useful reference for sun-protection strategies for patients.
