Could blue light reduce blood pressure?
12 November, 2018
Exposure to blue light may help combat hypertension, according to a recent study. If the findings are replicated in a larger sample, blue light could provide a cost-effective and side effect-free intervention.
The results of an investigation into the effects of blue light on high blood pressure were recently published in the European Journal of Preventative Cardiology.
High blood pressure, or hypertension, is widespread in the United States and many other Western countries.
According to the Centers for Disease Control and Prevention (CDC), high blood pressure is a primary or contributing cause of almost 1,000 deaths every day in the U.S.
Hypertension is also a risk factor for more serious conditions, such as heart attack, stroke, and kidney disease. For these reasons, managing blood pressure effectively is a high priority.
Currently, doctors usually prescribe medications such as angiotensin converting enzyme inhibitors and calcium channel blockers to help manage hypertension. Although these can be effective, side effects are common and include a persistent dry cough and dizziness.
Because high blood pressure is so prevalent, a great deal of research has investigated its causes. The importance of lifestyle, including diet and exercise, cannot be overstated, while other risk factors play smaller roles.
For instance, studies have demonstrated that exposure to sunlight influences hypertension. Blood pressure is, on average, lower during the summer months, and some research has linked high levels of long-term sunlight exposure to a reduced risk of dying from cardiovascular disease.
The bittersweet symphony of sunlight
Exposure to excessive levels of sunlight damages the skin, causing premature aging. Research has also established that ultraviolet (UV) light is a carcinogen — excessive exposure increases the risk of developing skin cancer.
On the other hand, as sunlight hits our skin, it drives a chemical reaction that produces vitamin D, which plays a range of essential roles in the body.
UV light also affects nitric oxide (NO) levels, and NO is an important signaling molecule in humans and virtually all other organisms.
The inner lining of blood vessels — called the endothelium — releases NO. This causes the smooth muscles around the blood vessels to relax, thereby lowering blood pressure.
When sunlight hits the skin, compounds such as nitrites break down to produce NO, which then diffuses into the deeper tissues and, finally, enters the blood vessels.
The interaction between sunlight, NO, and the smooth muscles of the blood vessels may explain why sunlight has a hypertension-minimizing effect.
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