What is the Right Amount of Sun Exposure?

When the sun comes out after many cloudy days, we feel happier and more energetic. There’s actually a biological explanation for that. On the other hand, excessive exposure to the sun’s ultraviolet (UV) rays can lead to sunburn and increase your risk for skin cancer. The fact is, the sun can affect nearly every aspect of your health. So, what is the right amount of sun exposure? Let’s find out.

Months Without Sunlight

If you live in Iceland or Scandinavia, you can spend several months with little or no direct sunlight. In these areas, depression rates run higher than average, and people consume more antidepressants, stimulants, sleeping pills and painkillers. What is it about the sun that makes us happy? It doesn’t just make you happy — it makes you healthy as well.

Circadian Rhythm

Human beings, just like many animals, are preprogrammed to respond to light. This means we sleep at night and are active during the day. This goes beyond just practical significance as hormones in your body also change with the timing of daylight. For instance, when you awaken, your body releases a cortisol surge to get you ready to face daily activity. Even specific genes get involved in this complex process of synchronizing your body and mind with the movement of the sun.

Melatonin is a substance that is produced by a tiny gland in your brain called the pineal gland. Normally, melatonin levels start to increase in the mid-late evening. Melatonin levels stay high during the night and, in the early morning, they begin to decline.

Not Enough Sunlight

You don’t have to live in Norway, however, to be affected by less daylight. During the winter months, for instance, your body’s melatonin production gets thrown off. In some cases, this can contribute to a condition called seasonal affective disorder (SAD). Less sunlight also leads to a decrease in serotonin levels, which is believed to be the main factor in the development of SAD.

SAD occurs in the late fall or winter. Symptoms of this disorder may include:

  • Feeling sad or depressed most of the day, almost every day
  • Low interest in activities, even ones you typically enjoy
  • Tiredness and fatigue
  • Sleep disturbance
  • Changes in your appetite or weight
  • Feeling sluggish, anxious, or sensitive
  • Trouble concentrating
  • Feeling hopeless, worthless or guilty
  • Thoughts of death or suicide

Winter Weight Gain

Another characteristic of serotonin is that its levels rise when you consume carbohydrates. This leads to a winter double whammy. It explains why some people gain weight during the winter months: you’re less active and you crave carbs to boost low serotonin levels. A similar explanation has been attributed to people who gain weight when they quit smoking. Since they feel bad without nicotine, they try to boost the feel-good hormone serotonin by eating more carbs.

Treatment for SAD

Now even though SAD is a subtype of depression, the first line of treatment doesn’t include pills. Instead, if you suffer from SAD, you should be treated with what you are missing: light. For this reason, commercially available light boxes are available to treat the disorder.

Also called phototherapy, the artificial light is used during the early morning hours to help reset your biological clock. In cases that don’t respond to light therapy alone, medications or psychotherapy may be needed. Some even consider moving to a place where there is more sunshine to avoid SAD symptoms. Still, even just a few days of light therapy may begin to bring things back to normal.

How Important Is Sunlight to Health?

If your internal biological clock isn’t aligned correctly, this can lead to depression, gastrointestinal problems, metabolic and cardiovascular disorders, weak immune systems and even shorter lifespans. There is some evidence that sleep disorders, which may be associated with insufficient sunlight, can increase your risk for diabetes, heart disease, and even some cancers.

Sun, Bones, Body and Brain Health

Sunlight is critical for normal bone metabolism. When UV rays hit your skin, this results in the production of vitamin D. This important vitamin helps regulate more than 1,000 human genes. Without vitamin D, you can’t absorb calcium and phosphorus from your intestines. This leads to weak bones and teeth. In children, vitamin D deficiency causes a condition called rickets and, in adults, it can lead to osteoporosis and bone fractures.

Some studies have even revealed a link between low vitamin D levels and an increased risk of Alzheimer’s disease. As we mentioned earlier, the sun may also be heart protective. The Journal of Investigative Dermatology states that sunlight may cause small amounts of nitric oxide to be released from the skin into your blood. Nitric oxide dilates blood vessels and lowers blood pressure to potentially protect you from a heart attack and stroke. This chemical may also help curb weight gain, according to animal studies.

The Dangerous Sun

Despite all the benefits of sunlight, too much of a good thing can be harmful. We all know that radiation can cause cancer. Sunlight carries UV radiation. If you get too much sun, you can get sunburn and your skin may age prematurely. Also, exposure to excessive sunlight is a major risk factor for the most dangerous form of skin cancer: melanoma. Severe sunburn before the age of 18 appears to increase the risk of melanoma. The other types of skin cancer (basal cell and squamous cell cancers) are also related to excessive sun exposure. These nonmelanoma cancers are not as dangerous.

The best prevention is to stay out of the sun, especially between 10 a.m. and 3 p.m. when the sun’s rays are most intense. If you can’t stay out of the sun, try these protective measures:

  • Wear a wide-brimmed hat that gives shade to your face, neck, and ears
  • Cover your skin as much as possible with clothing
  • Use sunscreen with a high sun protection factor (SPF) and that contains metal ingredients like zinc oxide and/or titanium dioxide
  • Seek shade as much as possible

What Kind of Skin Lesions are Dangerous?

Not all skin abnormalities or moles become cancerous. Some warning signs to watch out for are:

  • Asymmetry: Each half of a skin spot or mole doesn’t match the other
  • Border: Edges are irregular or blurred
  • Color: Uneven brown, black, tan, red, white or blue coloring
  • Diameter: Anything bigger than the size of a pencil eraser is suspicious, and any skin lesion that is growing should be evaluated
  • Evolving: Any new skin abnormality or mole that changes color, shape or size

Who’s at Risk for Skin Cancer?

People with an increased risk for skin cancer are those with:

  • Fair complexion or freckles
  • Light/blond or red hair and blue eyes
  • Skin that burns easily
  • A family history of skin cancer
  • Outdoor jobs or living in a sunny climate
  • History of severe sunburns

How Much Sunlight Should You Get?

There’s no exact formula about sunlight amount and health. In order to avoid vitamin D deficiency, it’s recommended to get about 10 to 15 minutes of exposure twice a week. You should not use sunscreen when getting this sunlight dosage. For most people, we get this amount of sun easily. Still, some are at risk for not getting enough sunlight, such as those who:

  • Work long hours indoors
  • Live in areas of little sun or frequent overcast days
  • Must stay indoors due to health issues

In these cases, vitamin D rich foods are helpful, such as:

  • Fatty fish: Salmon, tuna, and mackerel.
  • Beef liver, cheese, and egg yolks
  • Fortified milk (however, raw milk may be more nutritious overall)


Like many things in nature, the key to good health is a balance. Excessive sun exposure is certainly a major risk for skin cancers. You don’t need much sun exposure to prevent vitamin D deficiency, either. The best strategy is probably to get out early or in the late afternoon before or after the sun is at its most intense. If you combine this with exercise, the even better. Otherwise, stay indoors and take measures to protect your skin.