I intended to write this article on the first day of summer. But as I sat on my sun-kissed desk in California, a place known for its warm, dry summers, opal sky and scantily-clad liberals, I figured I better check the weather in London before continuing. With a few weeks of drizzle and clouds, it seems that summer in London is finally on the horizon.
The following are some of the health benefits that exposure to sunlight can bring, including tips to stay safe.
Whereas exposure to excessive levels of sunlight is detrimental to our health, moderate exposure can boost our physical and mental state. The aim is to enjoy the sun sensibly, to make enough vitamin D, while not increasing the risk of skin cancer.
1) Improves the quality of sleep
Waking up in sync with the sun’s natural light switches off melatonin, a hormone made in your pineal gland, associated with sleep onset. This is the reason why you feel alert during your waking hours and tired at bedtime – and discombobulated when you cross time zones after a long-haul flight. It is, therefore, a good idea to open the curtains in the morning and avoid artificial light once the sun goes down.
People with irregular sleeping schedules often have trouble sleeping or feel tired during waking hours. Several studies have shown that chronic disruption of circadian rhythms can lead to weight gain, slower thinking, and other physiological and behavioural changes – analogous to the changes observed in people who experience shift work or jet lag.
2) Reduces risk of some cancers
Prolonged sun exposure increases the risk of skin cancer, but vitamin D is also known to be protective against several cancers, including of the colon, kidney and breast. In a study conducted by the US National Cancer Institute, it was found that high levels of sunlight were significantly associated with reduced mortality from breast and colon cancer. Similar effects were seen in the bladder, womb, oesophagus and stomach cancer.
3) Improves mood
Sunlight triggers the release of serotonin, a neurotransmitter that helps to regulate mood. It’s no surprise that spending time outdoors improves mood and relieves stress. Lack of sunlight exposure in some people can even trigger a type of depression known as a seasonal affective disorder, which is treated with light therapy.
4) Lowers blood pressure
Rates of hypertension tend to be higher in the winter and in countries farther from the equator. A possible explanation is that exposure to sunlight causes nitric oxide in the skin to be absorbed into the bloodstream, which can help widen blood vessels and lower the pressure inside them.
5) Can help with some skin disorders
Sunlight can improve several skin complaints, such as psoriasis, eczema and acne. Indeed, eczema and psoriasis are sometimes treated with UV light (phototherapy). However, sunlight can aggravate other skin conditions, particularly rosacea.
6) Improves the musculoskeletal system
It is common knowledge that vitamin D is important for healthy bones by helping the body absorb calcium. In a 2013 large Danish study, researchers found that having a history of skin cancer was linked to a lower risk of hip fractures. This may be because those who developed skin cancer also had prolonged sun exposure.
Vitamin D is also important to muscle health, and people with low levels are more likely to experience muscle cramps and joint pain.
TIPS TO STAY SAFE
There are of course risks associated with sunlight. Prolonged exposure causes damage to the epidermis and to other parts of the skin such as the supporting elastic tissue in the dermis. This damage is known as actinic (solar) elastosis, and gives the skin a baggy, wrinkled appearance. A significant risk factor for malignant melanoma is sunburn, especially during childhood.
One of the major benefits of basking in the sun is to make vitamin D, which is useful because there is very little found in typical dietary sources. To prevent deficiency of vitamin D, it is recommended to have 2-3 sun exposures per week. Each exposure should last 20-30 minutes and be to bare skin.
2) Stay hydrated
Aim to drink more than the standard eight glasses a day. And get creative: put some frozen berries in your water or even some mint leaves and lime slices. Opt for snacks with high-water content such as watermelon, cantaloupe, tomatoes and cucumbers.
3) Wear sunscreen
Look for at least an SPF 30 and wear it when you know you’ll be out and about during the day. Wear sunscreens with both UVA and UVB protection. Blocking UVB may prevent burning (which is what the SPF number indicates), but UVA still delivers skin-damaging radiation (and isn’t rated).
To summarise, try to have 2-3 sun exposures per week, but avoid the sun when it is strong; and when you think you’re exceeding the recommended limit, cover up, or use high-factor sunscreen.