06 Dec 2019


Whether the Sun is our friend or foe? The debate on this can be perpetual, but we should understand that Sun is vitally vital for the existence of life on the Earth so it cannot be our enemy. Though there are some concerns regarding the risk of skin cancer and premature ageing on prolonged exposure to sunlight, it becomes less significant when we consider the numerous health benefits; we receive by exposure to sunlight. If we can follow the correct time and duration of sun exposure, we can eliminate this risk and get the optimum benefits of it.

Now let’s see these benefits one by one,


Sunlight is a must for the synthesis of Vitamin-D in our body. A majority of vitamin-D necessary for us synthesized from exposure of the skin to the sunlight. Upon exposure of skin to UVB light from the sun rays sets a chemical reaction which results in the synthesis of Vitamin D in its most natural form.


Adequate exposure to sunlight is necessary for the synthesis of vitamin D in the human body. Vitamin D plays a vital role in the production and secretion of hormone Insulin from pancreas and metabolism of glucose. Optimum levels of vitamin D in our body helps in improving the sensitivity of insulin, which is necessary for effective utilization of glucose from the blood into various cell and tissues. Normal insulin sensitivity helps in maintaining blood sugar levels within optimum limits and reducing risk of type-2 Diabetes Mellitus.


T-cell is a type of White Blood Cells (A type of immune cells). It plays a significant role in the fight against infection. When our skin gets exposed to sunlight for an adequate duration, the blue light spectrum of sunlight (with short-wavelength) helps these T-cells (Those which are present in skin) to circulate in the body more effectively. This makes them able to reach new infection quickly and stop it before it can cause any harm.


Though according to some studies, it is true that, too much exposure to Sunlight (Especially to Ultraviolet radiation) can put an individual at the risk of skin cancer. It also depends upon the duration of exposure, time of the day and skin type of an individual. On the contrary according to latest research, it has getting proved that vitamin D which is generated from exposure of the skin to the sunlight for an optimum duration and during the right time of day plays a protective role in reducing the risk of some types of cancers such as breast, colon, prostate and lung cancers.


Exposure of skin to the sunlight for an optimum duration helps in generation of Vitamin D in the human body. According to some studies, Optimum Vitamin D level in the body is associated with normal blood pressure levels. Thus, reducing the risk of Hypertension.

There is one more mechanism through which sunlight helps in Keeping our blood pressure levels within normal limits. On exposure to Sunlight Nitric oxide, a compound which is present in our skin gets transferred to the blood circulation. In the circulation, it relaxes the inner muscles of the blood vessels causing blood vessel lumen to widen. This increases blood flow and reduces blood pressure. In short, it reduces the risk of Hypertension.


Deficiency of vitamin D is associated with a disruption in the secretion of the hormone insulin. This results in the development of insulin resistance. Insulin resistance is one of the main culprits behind the accumulation of excess fat within our body and the development of obesity and metabolic syndrome. 80-90% of Vitamin D is formed through a chemical reaction when our skin is exposed to the sunlight. Thus, adequate exposure to the sunlight is necessary to have optimum levels of Vitamin D. Normal vitamin D levels protects against the development of insulin resistance within our body which in turn can help in preventing obesity.

The exposure of skin to Ultraviolet rays from sunlight releases Nitric oxide. Nitric oxide helps in the prevention of insulin resistance; thus, contributes to the prevention of obesity and metabolic syndrome.


Upon adequate and regular exposure to the sunlight, there is increased release of hormone serotonin from the brain. Serotonin is a hormone which is associated with improvement in mood, calmness and focus. This way, sunlight helps in boosting our mood and improving our focus.


Exposure to more light during the day and less light at night is critical for healthy sleep patterns. Exposure of Body to Sunlight during the day results in lesser production of melatonin (A sleep-inducing hormone) during daytime with increased release during the night thus, helps in calibrating the body’s biological clock. This correctly adjusts our circadian rhythm; we feel energetic during the day and feel sleepy during night. This helps in overcoming symptoms of insomnia and improves quality of sleep.


Alzheimer’s disease (AD), the primary cause of dementia worldwide, is characterized by progressive loss of memory and cognition.

Vitamin D, through various mechanisms, plays a vital role in the smooth functioning of blood vessels, nerve impulse transmission & calcium metabolism. It also offers protection against oxidative stress and inflammation to the nerve cells in the brain. Vitamin D deficiency hampers the functions mentioned above, which it performs, thus increasing the risk of Alzheimer’s disease. Regular and adequate exposure to sunlight helps in overcoming vitamin D deficiency; therefore, it can improve Alzheimer’s symptoms.


Sunlight helps in the healing of certain inflammatory skin conditions like Eczema and Psoriasis. Exposure of skin to the sunlight triggers the release of nitric oxide into the bloodstream. Once in the bloodstream nitric oxide activates specialized immune cells called as regulatory T-cells (Type of white blood cells). These cells once activated, dampen the ongoing inflammatory response in the skin. Thus, help in alleviating symptoms of eczema.

Exposure to the Ultra-Violet-B rays from sunlight can slow the rapid growth of skin cells that occurs with psoriasis. This may help to ease off the inflammation and reduce scaling in people with mild to moderate psoriasis


One of the significant functions of Vitamin D is the maintenance of Calcium levels in our blood within normal limits. It helps in the absorption of calcium present in the food we eat into the blood from intestines. Vitamin D deficiency is associated with reduced absorption of calcium. In chronic condition, calcium levels drop. To counter this, the calcium is removed from bones; thus, making them weak and brittle. Regular exposure to sunlight keeps our vitamin D levels within normal limits. This avoids calcium deficiency and indirectly protects our bones (Keeps them strong and healthy).


Serotonin is a hormone produced in our body which is associated with regulation of mood. Decreased Levels of serotonin manifest as low mood, tiredness, irritability and other depressive symptoms. Regular exposure to sunlight triggers the production of serotonin. When serotonin is produced in enough quantity, it improves the depressive symptoms and creates a feeling of happiness and well-being.


According to researchers, the bright outdoor sunlight helps in maintaining the correct distance between the lens and retina of a child’s developing eyes. Maintaining proper distance between lens and retina is necessary for kipping vision in focus. This can’t happen effectively with dim indoor light. As a result, when children spend too much time indoor, their eyes fail to grow correctly. This manifests as an increase in distance between retina and lens, causing far-away objects to look blur, I.e. Develops nearsightedness (Myopia). Thus, spending time outdoors in sunlight is necessary for better eye health.


Upon exposure of the skin to UV rays from sunlight, levels of specific chemical like urocanic acid are increased. This chemical cross the barrier between blood and brain cells and enters neurons (Nerve cells). In neurons, it gets metabolically converted to glutamate. Increase in glutamate levels results in increased transmission of impulses between them. This enhanced transmission through neurons results in improved learning and long-term memory and indirectly brain function.


As we have already seen that how getting regular exposure to sunlight is essential from the perspective of good health. Though sunlight is vitally crucial for our good health, we should understand that overexposure to sunlight can have some harmful effects such as Sunburns, Allergy and risk of skin cancers.

But don’t worry! If we take certain precautions while getting out in the sunlight, we can achieve all the health benefits associated with it and at the same time will be able to protect ourselves from these adverse effects. Let’s see what precaution we should take:

  • Limit the direct exposure of skin to sunlight for 10-15 minutes per day.

  • Fair skin individuals should expose their skin to the direct sunlight for a lesser time as compared to the darker skin individuals.

  • Morning Sunshine between 8 am to 11 am is ideal.

  • Avoid direct exposure of skin to sunlight between 12 noon to 4 pm.

  • Use appropriate sunscreen while venturing out during this period. (12 Noon- 4 pm)

  • To protect eyes, use sunglasses.

  • To get enough sunlight, exposure of only Hands and face is not enough, exposure of at least the portion of both Arms and Legs along with face is necessary to get the maximum benefit of sunlight



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  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356951/

  3. https://qz.com/868059/blue-light-from-sunlight-helps-improve-the-immune-system-by-circulating-t-cells/

  4. https://www.southampton.ac.uk/news/2014/01/20-the-sun-to-lower-your-blood-pressure.page#.Ut2klfZOmjk

  5. https://diabetes.diabetesjournals.org/content/63/11/3759

  6. https://www.medicalnewstoday.com/articles/320592.php#3

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  13. https://www.canr.msu.edu/news/the_benefit_of_daylight_for_our_eyesight

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