How sunlight affects blood pressure: What the science says

Many people associate sunshine with better mood and well-being. But the sun may have another, surprising benefit for our health: it can lower blood pressure. A landmark study showed that the sun's UVA rays can have a direct effect on our blood pressure.

What is UVA radiation?

Sunlight is made up of different types of radiation, including ultraviolet (UV) radiation. This is divided into UVA, UVB and UVC. UVA rays, which make up about 95% of the UV radiation that reaches the Earth's surface, penetrate deeply into the skin. For that reason they are considered to pose a higher risk of causing skin cancer. While UVB rays are mainly known for producing vitamin D, the positive effects of UVA rays on blood pressure have been less well studied.

Study overview

A research team led by Dr. Martin Opländer investigated in a 2009 study how UVA radiation affects blood pressure in healthy people. They found that whole-body exposure to UVA light significantly lowers blood pressure. But how exactly does that work?

How it lowers blood pressure

The skin contains certain molecules that store nitric oxide (NO). NO is an important messenger in the body that relaxes and dilates blood vessels, which lowers blood pressure. Normally NO is released through various biological processes, but the study shows that UVA rays can trigger this release as well. Under the influence of UVA light, the NO molecules in the skin are released and enter the bloodstream, where they exert their vasodilating effect.

The results in detail

The study found that after 20 minutes of UVA exposure, participants' systolic and diastolic blood pressure dropped noticeably. This effect lasted up to 60 minutes after exposure. Researchers also observed improved blood flow in participants' arms without a significant rise in heart rate. This suggests that UVA radiation has a direct relaxing effect on blood vessels.

What do these results mean for us?

The finding that UVA radiation can lower blood pressure opens up new possibilities for managing high blood pressure (hypertension), one of the most common chronic conditions worldwide. Especially at a time when many people avoid the sun because of the health risks of sunlight, moderate sun exposure under medical supervision could be beneficial. Of course, this does not replace medical treatment for high blood pressure, but it could be used as a complementary measure.

Conclusion

The sun not only benefits the mind, but may also help our cardiovascular system. The study by Dr. Opländer and his team shows that sunlight, especially UVA radiation, can be a natural way to lower blood pressure. However, as with everything in life, the dose makes the poison. A mindful and moderate approach to sun exposure is crucial to benefit from its positive effects without putting your skin health at risk. If you have high blood pressure, talk to your doctor about whether and how sun exposure could be included in your treatment plan.

Source:

https://pubmed.ncbi.nlm.nih.gov/19797169/

This article is from Tensana – the leading app since 2011, helping hundreds of thousands of people monitor their blood pressure every day. Our content is based on carefully researched, evidence-based data and is continuously updated (as of 01/2026).

Author Horst Klier has been closely involved with high blood pressure since 2002 – initially because he was personally affected and, since 2009, as the developer of Tensana – and is now regarded as a recognized blood pressure expert thanks to his app and specialist platform, used millions of times, as well as his numerous publications. As the author of several health guides and specialist articles, he communicates complex knowledge in a clear and practical way.