Spring has arrived and, before we know it, summer will be here with its long sunny days. Public health messages regarding sun exposure over the past century have focused on the hazards of too much exposure. Excessive sun exposure has been proven to increase the risk of skin cancer and prematurely age the skin. Recent research, however, has shown that some sun exposure has many health benefits and it should not be avoided. This blog will explore some of the benefits of sun exposure.
A commonly known benefit of sunlight is vitamin D, which is produced by the skin when it is exposed to sunlight. Vitamin D stabilises the calcium in bones, which helps to harden them. Not getting enough vitamin D can lead to several health issues, including decreased bone density, muscle aches, mood disorders and a weak immune system.
The circadian rhythm is a 24-hour rhythm during which almost every hormone, brain chemical and digestive enzyme (amongst other things) is pre-programmed to peak at a certain time of the day and then decline. This provides our organs with the necessary time they need to rest and repair, and ensures that they are functioning well. Sun exposure in the morning is vital in setting our circadian rhythm, or body clock, via specialised light sensors within the eyes.
Sun exposure is associated with serotonin production in the brain, with levels rising significantly with increased sun exposure. Serotonin is associated with mood boosting and helping a person feel calm and focused. The effect from lack of sunlight is well established with mood disorders like Seasonal Affective Disorder.
How much sunlight?
Unfortunately, there is not an exact measurement of the ideal level of sun exposure, as this depends on several factors, including skin type and how direct the sun’s rays are at a given point in time. According to the World Health Organisation (WHO), getting anywhere from 5 to 15 minutes of sunlight on your arms, hands and face 2 to 3 times per week is enough to receive sufficient vitamin D. For this to occur, however, the sunlight needs to penetrate the skin. It is essential to be sun-safe with sun exposure, applying sunscreen with a high protection factor (SPF) if you are going to be outside for a longer time period than this. Have a great summer!
Lambert et al. 2002 Effect of sunlight and season on serotonin turnover in the brain. Lancet. 2002 Dec 7;360(9348):1840-2.