Sensible sun exposure
Raises 25-OH vitamin D. Because the marker is none_established, this is not a health recommendation beyond the lab value.
Order of magnitude
Short uncovered intervals, without sunburn.
The interesting finding is that the blood-pressure effect of ultraviolet light appears to be independent of vitamin D: several of the studies attribute it to nitric oxide released from stores in the skin.
Effects in detail
Each row is a directed edge from our database, with range, latency, evidence grade and the condition under which it applies at all.
| Marker | Effect | Latency | Mode of action | Outcome | Evidence | Condition | Sources |
|---|---|---|---|---|---|---|---|
| Diastolic blood pressure | helps. Lowers Direction known, size not established A systematic review of 14 studies found that most reported a blood-pressure reduction with ultraviolet exposure, particularly UVA, with several attributing it to nitric oxide released from stores in the skin rather than to vitamin D. The mechanistic point is the interesting one: if the effect is nitric-oxide mediated then it cannot be obtained from a vitamin D capsule, which fits the null vitamin D outcome trials. | not specified | chronic | unclear | Evidence grade C | applies regardless of the starting value | |
| Systolic blood pressure | helps. Lowers Direction known, size not established A systematic review of 14 studies found that most reported a blood-pressure reduction with ultraviolet exposure, particularly UVA, with several attributing it to nitric oxide released from stores in the skin rather than to vitamin D. The mechanistic point is the interesting one: if the effect is nitric-oxide mediated then it cannot be obtained from a vitamin D capsule, which fits the null vitamin D outcome trials. | not specified | chronic | unclear | Evidence grade C | applies regardless of the starting value |
What this measure costs
Counteracting effects of the same measure.
No counteracting effect is on file for this measure. That does not mean there is none, only that we found no defensible edge.
Moves without implying progress
Informational or no established effect: the marker moves or was checked, and that is not progress.
| Marker | Effect | Latency | Mode of action | Outcome | Evidence | Condition | Sources |
|---|---|---|---|---|---|---|---|
| 25-OH vitamin D | moves, and does not count. Raises Direction known, size not established With 90 % of the skin exposed to UVB three times a week for four weeks, 80 % of the variation in 25-OH-D response was explained by the UVB dose and the person's skin tone. No absolute magnitude is available, so this row is direction and dose-dependence only. | 4–4 weeks | chronic | unclear | Evidence grade B | applies regardless of the starting value |
Sources
Full details of every study the rows above rely on.
Ultraviolet-B radiation increases serum 25-hydroxyvitamin D levels: the effect of UVB dose and skin color
Armas et al. · Journal of the American Academy of Dermatology · 2007 · Randomised trial
Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline
Demay et al. · Journal of Clinical Endocrinology and Metabolism · 2024 · Guideline
Effects of ultraviolet light exposure on blood pressure: a systematic review
Ghadjar et al. · Photochemical and Photobiological Sciences · 2026 · Review
Vitamin D Supplementation and Sunlight Exposure on Serum Vitamin D Concentrations in 2 Parallel, Double-Blind, Randomized, Placebo-Controlled Trials
Mendes et al. · The Journal of Nutrition · 2021 · Randomised trial