When you spend time in the sun, the ultraviolet (UVR) rays hit your skin and trigger vitamin D synthesis. Not only does this fat-soluble vitamin help you store calcium and phosphorus which leads to strong bones, but it also helps reduce inflammation, fight infections, and boost mood.
So how much sunlight do you really need? Well, it depends on several factors. Generally, most experts recommend 5-30 minutes of sunlight at least twice a week.
However, getting sunlight does not come without risks. For instance, too much sun can cause skin cancer, premature aging, wrinkles, and other skin damage. Some research also suggests that too much sunlight can suppress your skin’s natural defenses and lower immune system functioning. For these reasons, you should spend time in the sun with caution and input from your healthcare provider.
Research on how much sunlight people need—particularly without sunscreen—is currently mixed. However, some researchers report that people usually need 5-30 minutes of sun exposure between 10 a.m. and 4 p.m. at least twice a week without sunscreen to promote vitamin D synthesis.
Avoiding the sun could have dire consequences. One study found that inadequate sun exposure could be linked to 340,000 deaths yearly in the United States. Meanwhile, researchers in another all-cause mortality study found that avoiding the sun increases a person’s risk of death on par with people who smoke.
However, the American Academy of Dermatology does not advise exposing your skin to the sun without sunscreen and stresses that there is no safe level of sun exposure. Likewise, the Centers for Disease Control and Prevention (CDC) says the sun’s UV rays can damage your skin in as little as 15 minutes and recommends staying in the shade, especially midday.
For this reason, the best way to determine how much sun you need each day—and whether or not that time in the sun should be with or without sunscreen—is to talk to a healthcare provider familiar with your health history and medical needs. Together, you can decide what is right for you.
Several factors can influence how much sun you need. These may include your overall vitamin D levels, medical history, age, and skin tone. Even your geographical location can play a role in your sunlight needs.
For instance, the more melanin (a substance your body makes to add pigment to your skin and hair) you have in your skin, the harder it is for your skin to produce vitamin D from sunlight. As a result, Black Americans usually have lower vitamin D levels than lighter-skinned Americans. That said, people with darker skin tones typically need more time in the sun to reap the effects of vitamin D.
Meanwhile, another study found that 90% of white people would need about 30 minutes of midday summer sun three times per week to achieve adequate vitamin D. But, the research notes that more exposure is necessary in other seasons, at different times of day, and for people with darker skin.
There also is the concern about how the sun’s UV rays affect the skin and its ability to cause a sunburn. Generally speaking, those with lighter skin have a higher risk of skin damage, so healthcare providers and researchers recommend spending less time in the sun. Specifically, researchers recommend maximum time limits to spend in the sun based on your skin tone:
| Skin Type | Maximum Time in the Sun |
|---|---|
| I: Very light skin | 10 minutes |
| II: Light skin | 20 minutes |
| III: Light or light brown skin | 30 minutes |
| IV: Olive or light brown skin | 50 minutes |
| V: Dark brown skin | More than 60 minutes |
| VI: Dark brown or black skin | More than 60 minutes |
While the above time limits are a helpful guide, it’s best to ask your healthcare provider how much sun is too much—specifically for your own needs and underlying health conditions.
In addition to its vitamin D-boosting capabilities, the sun may help regulate sleep and boost mood, among other factors.
Boosts Mood
Getting adequate sunlight can boost your mood. Not only is light used to treat different types of depression, like seasonal affective disorder (SAD), but getting sunlight can also reduce the likelihood of developing depression.
Researchers studied 400,000 people who spent 2.5 hours outside and found that for each hour spent outside in natural light, there was a decrease in the risk of developing long-term depression. Researchers also found that people in the study used fewer antidepressants and reported improvements in mood and general feelings of happiness.
Regulates Sleep
Getting enough sunlight can also regulate your body’s hormones that affect your circadian rhythm—your body’s internal clock. Your circadian rhythm is most sensitive to sunlight about one hour after waking up in the morning and about two hours before bed.
Additionally, exposure to light in the morning will likely make it easier for you to fall asleep at night and help you remain alert throughout the day. Another study also found that the more natural light people in an office received, the better sleep they experienced, and the more productive they were at work.
May Lower Blood Pressure
High blood pressure is a leading cause of premature death and disease. Consequently, finding ways to reduce blood pressure readings is at the top of mind for many researchers. One team found that getting sunlight may help lower blood pressure. Not getting enough sunlight may also be a risk factor for hypertension.
Another study found that when sunlight touches your skin, a compound called nitric oxide is released into the blood vessels. This process can help bring blood pressure readings down and may ultimately lower the risks of heart attack and stroke.
Can Aid Weight Loss
Although research is limited, there may be a connection between getting more sunlight and weight loss. According to one study, the fat cells beneath your top layer of skin are sensitive to the sun’s rays and shrink when exposed to the sun.
Researchers speculate that this could be the reason why people tend to gain weight during the winter months or in northern areas where there is little sunlight. That said, more research is needed before getting more sunlight is recommended as a weight management technique.
When it comes to getting regular sunlight, talk to your healthcare provider about what is right for you. Your family and personal medical history, age, and skin tone all play a role in how much sun time your provider may recommend. If you are spending more time in the sun, here are some things you can do to protect your skin and stay safe:
- Wear protective clothing and sunglasses to reduce the risk of sunburn
- Apply sunscreen and reapply the product every two hours
- Check the UV index to help avoid overexposure to sunlight
The chart below can help you understand the UV index and how much exposure from the sun you may be getting for each number on the index.
| UV Index | Exposure Level |
|---|---|
| 0 to 2 | Minimal |
| 3 to 4 | Low |
| 5 to 6 | Moderate |
| 7 to 9 | High |
| 10 | Very High |
| 11 & up | Extreme |
Any time you consider spending time in the sun, you need to balance the benefits of sun exposure with the risks for skin damage—such as premature aging or wrinkles, sunspots, and skin cancer.
Spending a lot of time in the sun on a hot day also increases the risk of a heat-related illness like heat stroke, heat exhaustion, sunburn, and dehydration.
Take precautions to protect your skin and hydrate well if you plan to be in the sun.
Getting sunlight consistently may be the key to improved wellness and adequate vitamin D levels. On the other hand, too much sun exposure can also be harmful. If you want to reap the benefits of sunlight, talk to a healthcare provider about how much sun is right for you given your skin tone, age, and medical history.
While sunlight can do a lot of good, it also can cause skin cancer, so it’s important to strive for a balance between the risks and the rewards.