For decades, many older adults have been encouraged to avoid the sun as much as possible to reduce skin cancer risk. But a large Swedish study following nearly 30,000 women for about 20 years suggests that complete sun avoidance may also carry health risks—particularly for heart health and overall longevity.

Because cardiovascular health strongly influences brain health, mobility, and independence later in life, these findings offer a more nuanced view of how sunlight fits into healthy aging.

What the Swedish Study Found

The research comes from the Melanoma in Southern Sweden (MISS) cohort, which tracked 29,518 women aged 25–64 at baseline. Participants reported their sun habits, and researchers used modern competing‑risk analysis to examine major causes of death over two decades.

Compared with women who had the highest sun exposure, those who avoided sun exposure had:

• higher risk of cardiovascular death
• higher risk of death from non‑cancer, non‑cardiovascular causes
• shorter life expectancy — roughly 0.6 to 2.1 years shorter depending on age group

One surprising detail: women with more sun exposure had a higher proportion of cancer deaths, but this was because they lived longer overall, allowing cancer to become a more common cause of death later in life.

The authors concluded that avoiding sun exposure was a risk factor for death of a similar magnitude as smoking in this cohort.

Why Sunlight Might Influence Longevity

The study did not prove exactly why sunlight was linked with longer life, but several well‑studied mechanisms may help explain the pattern:

• Vitamin D production: Sunlight triggers vitamin D synthesis, which supports bone strength, immune function, and possibly cardiovascular and cognitive health.
• Blood vessel effects: Sunlight may help blood vessels relax, supporting healthier blood pressure in some individuals.
• Circadian rhythm: Daylight exposure helps regulate sleep–wake cycles, which are closely tied to cognitive function and mood.
• Outdoor activity: People who spend more time outside often move more, which benefits heart and brain health.

These factors accumulate over time, which may explain why long‑term sun avoidance was associated with shorter life expectancy in the MISS cohort.

What About Vitamin D Supplements?

Because sunlight and vitamin D are closely linked, researchers have also examined whether vitamin D supplements can influence longevity. A large meta‑analysis published in PLOS Medicine pooled data from randomized trials of vitamin D supplementation.

Overall, vitamin D supplements showed:

• no clear reduction in all‑cause mortality in the general trial populations
• a modest reduction in cancer mortality in some analyses

This suggests that while vitamin D supplements can be helpful for specific needs—especially bone health—they do not fully replicate the broader survival benefits associated with sensible sun exposure in the Swedish study.

Balancing Sun Safety With Healthy Exposure

None of this means that prolonged, unprotected sun exposure is safe. Skin cancer risk is real, especially for fair‑skinned individuals or those with a history of skin cancer.

Instead, the findings support a balanced approach:

• spending short periods outdoors most days, especially in the morning or late afternoon
• avoiding sunburn at all costs
• using hats, shade, or clothing for longer outings
• protecting areas with prior skin cancers while allowing limited exposure elsewhere, as advised by your clinician

The goal is not to eliminate sunlight entirely, but to enjoy it safely and consistently.

Key Takeaways for Older Adults

The MISS cohort suggests that complete sun avoidance may shorten life expectancy, largely by increasing cardiovascular and other non‑cancer deaths. Moderate, sensible sun exposure—combined with sun‑safe habits—may support healthier aging, better sleep, stronger bones, and potentially longer life.

As always, individual medical history matters. If you have been advised to avoid sun exposure for specific reasons, follow your clinician’s guidance.

Reference

The study is available here: Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort