LONDON: Spending a little time in the sun can benefit physical and mental health, but experts say the amount people need varies widely depending on skin type, location, season and ultraviolet radiation levels.
Moderate sun exposure helps the body produce vitamin D, which supports bone health, muscle function and the immune system. Sunlight may also contribute to better sleep, improved mood and lower blood pressure.
However, excessive exposure to ultraviolet radiation remains a major cause of skin cancer, meaning health experts increasingly recommend a balance between getting enough daylight and protecting the skin.
Short and regular exposure
Rebecca Mason, professor of physiology at the University of Sydney, says vitamin D production is most efficient when exposure is brief and regular rather than prolonged.
For people with lighter skin, exposing the hands, arms or legs to sunshine for just a few minutes on most days may be enough during summer.
People with darker skin generally need longer exposure because higher levels of melanin reduce the skin’s ability to produce vitamin D quickly. One UK study suggested people with dark brown skin could need around 25 minutes of midday sunshine during spring and summer.
The exact amount, however, depends on the UV Index and local conditions.
Experts caution that people should never stay in the sun long enough to burn.
Benefits beyond vitamin D
Sunlight also influences the body’s internal clock.
Morning daylight helps suppress melatonin, the hormone associated with sleep, while supporting alertness during the day. Research has linked greater daytime light exposure with improved sleep, reaction times and cognitive performance.
Sunlight can also increase serotonin levels in the brain, which may help improve mood and concentration.
Studies have additionally suggested that exposure to sunlight can trigger the release of nitric oxide in the skin, helping blood vessels widen and potentially lowering blood pressure.
Too much sun carries risks
The benefits do not mean more exposure is always better.
Spending excessive periods in strong sunshine raises the risk of sunburn, premature skin ageing, pigmentation and skin cancer. UV exposure is considered the leading preventable cause of most skin cancers.
People with very pale skin, many moles, a personal or family history of melanoma, or those taking immunosuppressant medicines may need stronger precautions.
Experts recommend protective clothing, shade, sunscreen and sunglasses when UV levels are high.
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Children and teenagers require particular protection because substantial UV exposure early in life can increase the likelihood of developing skin cancer later.
What about winter?
In colder or less sunny regions, the body may struggle to produce enough vitamin D during winter.
People with darker skin, limited outdoor access or those who regularly cover most of their skin may be at greater risk of deficiency.
Vitamin D supplements and fortified foods can help where sunlight is insufficient, although experts warn against taking excessive doses.
The overall message is simple: small, regular amounts of sunshine can be beneficial, but prolonged unprotected exposure is unnecessary and potentially harmful.
For most people, the safest approach is to enjoy daylight regularly while adjusting protection according to skin type, season and the local UV Index.
