It is not just plants that absorb and metabolize sunlight. Human beings do it too. However, the relationship between sun exposure and health in humans isn’t as straightforward as we might want it to be. Genes are a factor of how humans metabolize sunlight; as is skin type. For instance, people with pale skin that burns easily in the sun are likely to get skin cancer if exposed to too much sun. The timing and duration of exposure is also a crucial factor when it comes to how our bodies metabolize sunlight.

That being said, a number of scientists suggest that the health benefits of moderate sun exposure may in fact outweigh the risks. Researchers from the University of Edinburgh in the UK, for example, specifically point out that the heart-health benefits of sun exposure far outweigh the risk of developing skin cancer. Here are ten huge health benefits of moderate sun exposure you absolutely should know about.

1. Sun exposure lowers blood pressure.

In a landmark study, a group of researchers at the University of Edinburgh found that a compound called nitric oxide that helps lower blood pressure is released into the blood vessels as soon as sunlight touches the skin. This finding was important because until then it was thought that sunlight’s only health benefits to humans was to stimulate production of vitamin D. Richard Weller, Senior Lecturer in Dermatology, and colleagues, however, found that sun exposure can not only improve health, but also prolong life. That's because the benefits of lower blood pressure include cutting risk of heart attacks and strokes. These benefits, says, Weller “far outweigh the risk of getting skin cancer.”

2. Sun exposure improves bone health.

It is a well known fact that vitamin D stimulates the absorption of bone-strengthening calcium and phosphorus in the body. However, emerging research also indicates there is a direct correlation between bone density and vitamin D3. Vitamin D3 is a fat-soluble vitamin formed during the process of Vitamin D manufacture when sunlight hits the skin. It regulates calcium absorption. When you have higher levels of vitamin D3 in your blood, you are at a lower risk of suffering fractures of virtually all types. On the other hand, lower levels of vitamin D3 in the blood are associated with higher rate of all types of fractures. This is why sun exposure is especially important for bone health in older adults.

3. Sun exposure improves brain function.

Aside from promoting bone health and regulating vital calcium levels, scientists have now linked vitamin D with a number of functions throughout the body, including the functioning of the brain. One study led by neuroscientist David Llewellyn of the University of Cambridge, assessed vitamin D levels in more than 1,700 men and women from England, aged 65 or older and found that cognitive function reduced the lower the subjects’ vitamin D levels were. However, more studies have found sunlight could help spur nerve cell growth in the hippocampus, which is the part of the brain responsible for forming, organizing and storing of memories.

4. Sun exposure eases mild depression.

Sunlight deprivation can cause a condition called seasonal affective disorder (SAD). SAD is a form of depression common in the winter months. It is also common in people who work long hours in office buildings and hardly get out for some sun. Moderate sun exposure, however, increases levels of natural antidepressants in the brain that can actually help relieve this and other forms of mild depression. That’s because on sunny days the brain produces more serotonin, a mood-lifting chemical, than on darker days.

5. Sun exposure improves sleep quality.

When sunlight hits our eyes, a message is sent to the pineal gland in the brain and production of melatonin (a hormone that makes us drowsy and helps us sleep) is shut down until the sun goes down again. Your body gets a clear signal that it's no longer night and this helps to maintain a normal circadian rhythm. When it gets dark outside, your body gets the signal again and you feel tired and drowsy at bedtime. Low levels of melatonin production at night due to overproduction during the day has been linked to poor sleep quality, especially in older adults. Ditch the sunglasses early in the morning when you wake up if possible so your body gets the message that it is day and triggers the pineal gland to stop releasing melatonin.

6. Sun exposure lessens Alzheimer's symptoms.

Clinical research has shown Alzheimer's patients who are exposed to the sun throughout the day from 9 a.m. to 6 p.m. followed by darkness at night score better on mental exams and improve some aspects of the disease. For example, one study published in the Journal of the American Medical Association found that Alzheimer's patients exposed to bright light had fewer symptoms of depression, nighttime wakefulness, agitation and lost less function than those exposed to dim daytime lighting. The researchers attributed these improvements to more regular circadian rhythms.

7. Sun exposure heals some skin disorders.

Sunlight promotes healing of skin disorders, such as acne, psoriasis, eczema, jaundice and other fungal skin infections. In one study, for example, a four-week outdoor sunbathing therapy was successfully used to significantly clear symptoms of psoriasis in 84% of subjects. While sun exposure has a therapeutic effect on the skin and sunlight has been successfully used to treat skin disorders, this alternative treatment method should be done under medical supervision to prevent negative side-effects of UV radiation and to ensure the benefits outweigh the risks.

8. Sun exposure boosts growth in children.

This benefit is especially true for infants. Studies reveal the amount of sun exposure in the first few months of a baby’s life has an effect on how tall the child grows. Many cultures around the world recognize this fact and expose children to mild sun to boost growth and height.

9. Sun exposure enhances the immune system.

Sun exposure can help suppress an overactive immune system, which could explain why sunlight is used to treat autoimmune diseases like psoriasis. And since white blood cells increase with sun exposure and they play a key role in fighting diseases and defending the body against infection, moderate sun exposure is very helpful for your immune system.

10. Sun exposure reduces risk of certain cancers.

Vitamin D deficiency increases your risk of many cancers, especially breast and colon cancer. However, eating whole foods and getting some sun can send breast cancer into remission. This connection was first made by Drs. Frank and Cedric Garland from the University of California who observed that the incidence of colon cancer was nearly three times higher in New York than in New Mexico. Subsequent studies have since shown vitamin D supplementation produce a dramatic 60% drop in risk of developing any form of cancer. This confirms the benefits of vitamin D and sun exposure in reducing risk of cancer.

Bottom line:

Sunshine does have its benefits, but it's still the number one cause of skin cancer. Experts recommend no more than 15 to 20 minutes of direct sunlight daily for a healthy adult. After that, apply sunscreen with a minimum Sun Protection Factor (SPF) of 30. Remember skin color, where you live and how much skin you expose to the sun affect how much vitamin D you can produce.