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Sunlight and Cardiovascular Disease

Sunlight and Cardiovascular Disease

The hazards of staying out too long in the sun are well known – sunburn, increasing risk of skin cancer, skin ageing, to name a few. However, in vitro laboratory research from UKHSA (and independently researched by others), shows that some sunlight activates nitric oxide, a molecule in the skin known to reduce blood pressure (Liu 2014). High blood pressure affects around 25% of UK adults and is a leading risk factor for cardiovascular disease; therefore, strategies to alleviate this burden of disease are a key priority (PHE Guidance 2017).

Nitric oxide is a small molecule that is released in the skin after exposure to ultraviolet light (present in sunlight) and acts to expand the blood vessels in the body. This lowers blood pressure, thus reducing the risk of developing cardiovascular disease. The exact size of effect sunlight could have on cardiovascular health by this mechanism is unknown, however early clinical trials, epidemiological and laboratory data are supportive of this protective mechanism (Liu 2014, Pelegrino 2020, Weller 2020, Weller 2022).

Author: Paul O'Mahoney UKHSA Research Profile

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Sunlight and the Impact on Blood Pressure

Recently published work by researchers at UKHSA has shown that low exposures to natural sunlight (around 10 minutes on a clear summer day) can expand blood vessels in vitro. Importantly, these doses of sunlight produced no detrimental effects to the cells. It may be possible to be protected against the harmful effects of sunlight while taking advantage of the benefits to our health that sunlight has to offer, though further work is needed to study these effects in humans. Research on this area continues under the NIHR Health Protection Research Unit in Chemical and Radiation Threats and Hazards and in collaboration with partner universities.

Further Reading:

Low-dose daylight exposure induces nitric oxide release and maintains cell viability in vitro Authors- Hazell, Khazova and O'Mahoney (2023).

Post-exposure persistence of nitric oxide up regulation in skin cells irradiated by UV-A, Authors- Hazell, Khazova Cohen, Felton and Raj (2022).

Ultraviolet radiation - induced production of nitric oxide: a multi-cell and multi-donor analysis, Authors - Holliman, Lowe, Cohen, Felton and Raj (2017).

Sunlight and the Impact on Blood Pressure

Blood pressure monitoring (Image source:

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