Sunlight has been the most sought-after resource since the genesis of life. Not only is it important for plants to flourish, but it also affects animals as well. The human body is significantly influenced by sunlight exposure. There is a reason why the Sun is celebrated as a god in several religions, being the bringer of life and joy.
Although we’re used to hearing how exposure to sunlight is harmful to our skin, that’s just glancing at the surface. This article looks into how sunlight exposure has profound physical and mental health benefits.
Sunlight Stimulates Vitamin-D Synthesis
Vitamin D is one of the most unique chemicals our body produces. Although it is synthesized by the skin itself, it requires some external stimulus to trigger the synthesis. Vitamin D exists in 2 forms.
- Ergocalciferol or Vitamin D2 is found in sun-exposed mushrooms. It is obtained from the irradiation of the yeast sterol ergosterol. Ergosterol is a sterol residing in the cell membranes of fungi. It maintains the integrity of the cell membrane, similar to cholesterol in mammals.
- Cholecalciferol or Vitamin D3 is the one synthesized by humans. This is triggered by the irradiation of the skin with UVB light from the Sun.
D3 is the more potent of the two forms, as it raises vitamin D levels about twice as much as D2.
It is evident from these that sunlight is vital for the synthesis of vitamin D. Although you may supplement with dietary vitamin D, sun exposure is still important. Vitamin D produced in the skin can last twice as long in the blood compared to ingested vitamin D.
Although the amount of sunlight exposure depends on various factors, the Vitamin D Council states:
- 15 minutes for a person with light skin (pale skin synthesizes vitamin D more rapidly)
- A couple of hours for a person with darker skin
Optimal vitamin D levels have various health benefits, including –
- Better immune response due to an increase in anti-inflammatory and immunoregulatory responses
- Optimal calcium levels
- Improved bone health
- Prevention of diseases – type 1 diabetes, multiple sclerosis, and various forms of cancer.
Your Mood Is Directly Affected by Sunlight
Researchers at the National Institute for Mental Health (NIMH) found that light affects mood regulation. A photoreceptor in the eye – intrinsically photosensitive retinal ganglion cells (ipRGCs) contain melanopsin, a light-sensitive protein. It has been found that light reaches and affects the brain’s mood-regulating regions via the ipRGCs.
Besides this, sunlight is also believed to increase the release of serotonin in the brain. Serotonin is a hormone (neurotransmitter) responsible for the regulation of mood, cognition, learning, and memory among other physiological processes. Simply said, serotonin is associated with boosting mood and a feeling of happiness and focus.
These facts have been vital in the understanding of seasonal affective disorder (SAD). This is a form of depression affecting people in the winter when there’s less sunlight. Studies have also suggested that decreased exposure to sunlight increases the probability of cognitive impairment.
How It Affects Sleep
Our bodies don’t have to rely on alarms, they have an internal clock ticking at all times. The circadian rhythms are physical, mental, and behavioral changes that follow a 24-hour cycle. Exposure to sunlight has a powerful effect on this clock. It can even help you manipulate your body for the most optimal routine.
Exposure to light at specific times regulates sleep, even synchronizing the body with sunrise and sunset. Bright evening light a couple of hours before bed makes you sleep later, while bright morning light shifts the sleep time earlier.
Sunlight also keeps you more attentive. Melatonin is a hormone produced in the body which induces the feeling of drowsiness. Although it facilitates sleep, it can also cause daytime drowsiness. Sunlight exposure is shown to slow or halt the production of melatonin, increasing focus and energy levels.
Moderation is Key When It Comes to Sun Exposure
While there are many reasons to get out in the Sun, you must take some preventive measures as well. Sunlight emits 3 types of UV (ultraviolet) rays – UVA, UVB, and UVC. Of these, UVC does not reach the Earth because of the ozone layer. The UVB rays, however, can be extremely harmful.
Having slightly more energy than UVA rays, UVB causes sunburns, and can even damage the DNA in skin cells. These are the main cause of skin cancer.
People with fair skin tend to get affected more rapidly than those with darker skin. The general recommendation for sun exposure is 5-15 minutes for pale-skinned people. This bumps up anywhere from 30 minutes to an hour for people with darker skin.
It is important to note that sunscreen or clothing covering the skin does not allow for the production of vitamin D. For extended exposure to the sun, however, sunscreen application is a necessity. SPF 30 sunscreens block around 97% of UVB rays. Each skin type has a specific sunscreen suitable, so do your research before getting one.