Most of us know the dangers of too much sun — sunburns, dark spots and even skin cancer. But not enough people talk about the other side of the equation: What happens when you don’t get enough sunlight? 

The same UV rays that can damage your skin also help your body make vitamin D, a nutrient that supports strong bones, a healthy immune system and steady energy. Without it, you could start to feel the effects in surprising, not-so-pleasant ways. 

So, how much sun is enough, and what really happens when you don’t get it? Let’s dive in. 

What Happens When You Don’t Get Enough Sunlight? 

Not getting enough sunlight is surprisingly common. There are several reasons individuals might fall short on natural light.Whether they live in areas with long winters and short days or have a medical condition that makes going outside difficult, sunlight deficiency affects more people than you might think. 

Here’s what can happen if your body doesn’t get enough natural light: 

Can a Lack of Sunlight Weaken Your Immune System? 

Vitamin D helps your immune system produce proteins that fight pathogens. Without enough sunlight, you may experience a weakened immune system and become more susceptible to getting the flu, cold or other infections. 

Why Does Low Sunlight Cause Fatigue? 

Sunlight can boost serotonin levels in the brain, creating a sense of calm and boosting your mood. Without sunlight, your energy levels may dip, triggering drowsiness even when you’ve received an adequate amount of sleep.  

Can Reduced Sunlight Trigger Seasonal Affective Disorder (SAD)? 

Yes, the sun (or lack thereof) may be partially to blame for those seasonal mood changes. The decrease in sunlight during winter months can impact your internal clock — also known as circadian rhythm — which may disrupt your sleep schedule and lead to feelings of depression.  

How Does Low Sunlight Affect Bone Health? 

Vitamin D is key for calcium absorption. Without it, you’re prone to weaker bones. 

Studies have shown that low vitamin D levels can lead to lower bone density, which may be a leading factor in causing potential fractures or osteoporosis. 

Can Not Getting Enough Sun Affect Your Weight? 

Yes, insufficient sunlight can contribute to weight gain over time. We’ve already mentioned that a lack of sunlight can affect your circadian rhythm. When that biological clock is altered, sometimes it feels more challenging to sleep at night. If that happens repeatedly, you could feel tired more frequently, lending less energy for a regular exercise routine. 

In addition, the sun may also play a part in keeping your metabolism on track. One study found that UV rays cause nitric oxide production, which helps your metabolism function properly. Without sunlight, your metabolism could slow down, making it easier to gain weight. 

How Much Sun Is Enough? 

The amount of sun you need depends on several factors, but you don’t need to spend hours baking in the sun to get enough vitamin D. Just a few minutes of exposure a few times a week can make a big difference.  

Does Skin Color Affect How Much Sun You Need? 

Yes. Fair-skinned individuals usually have less melanin (the pigment that determines your skin color) than people with dark skin. Melanin acts as a natural sunscreen to protect your skin from UV rays.   

This means that people with darker skin often need to spend longer periods in the sun to receive the same amount of vitamin D as someone with lighter skin.  

What Is the Best Time of Day for Sun Exposure? 

UV rays are at their peak during midday. By choosing to take a stroll in the early afternoon, you won’t need to stay outside as long to get an ample amount of sunlight and vitamin D.  

How Do Your Clothes Impact the Amount of Sun You Get? 

When it’s cold, layers of clothing keep you warm but also block sunlight from reaching your skin. The more skin you cover, the longer you’ll need to spend outdoors to absorb enough vitamin D. 

Overall, the amount of sun you need depends on the factors listed above. But if you’re able to expose one-third of your skin by wearing shorts and a T-shirt, then spending 10 to 30 minutes in the sun three times a week is plenty of time to ensure you’re getting enough sunlight. 

Gain Practical Knowledge for Careers in Medicine at the University of Florida 

If you’re interested in giving your resume a sizeable boost, look no further than the University of Florida’s online Medical Physiology Graduate Certificate program. In as little as one semester, you can complete the 9 to 14 credit hours needed to earn your certificate. Our rigorous and up-to-date program content is ideal for a variety of professionals in the medical community, including: 

• Nurses 
• Physician assistants 
• Medical school applicants 
• Individuals preparing for the MCAT 
• High school or community college professors teaching biology or physiology courses 

Get more details about our online Medical Physiology Graduate Certificate program or take the next step and apply today. 

Sources:
https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166406/
https://pubmed.ncbi.nlm.nih.gov/26538987/