The Body Needs Sunlight to Thrive

Body Needs Sunlight to Thrive

Without light, we wouldn’t exist. Just like plants and animals, humans require sunlight. The human body has photoreceptors (cells that respond to light) in the eyes and skin that detect light, signal various pathways in the body, and are able to even convert that light into energy.

If you’ve been following along, you know I moved from Oregon to Texas two weeks ago. The biggest change that I didn’t anticipate when making this move was the impact of light in my new environment. Of course I knew that I was moving to a sunny climate, but the impact it has made in a short time has been incredible.

Anecdotally I can share that in the last two weeks, my energy is improved, I bounce out of bed wanting to exercise, and my drive to sleep at night is stronger. My mood feels lighter, and overall I feel more vibrant.

Why We Need Sunlight to Thrive

Light is what sets our circadian rhythm. The circadian rhythm determines when we wake up, when we get tired, how easily we fall asleep, when we feel hunger, and more. It drives the metabolism, impacts body weight, impacts the microbiome, and affects hormone functions in the body.

Sunlight is key for vitamin D synthesis. While supplementation is a tool that can sometimes be helpful and necessary, it misses the benefit from natural vitamin D production in our skin. Supplementing vitamin D can displace vitamins K and A which can cause other issues in the body. This doesn’t mean stop supplementing—always talk to your doctor. The threshold to create vitamin D is much lower than the risk of sunburn, so ideally getting sun in the morning and late afternoon is best to get the benefits of sunlight without risk of burning.

Sunlight increases production of serotonin, our happy hormone, which is also a precursor to melatonin. Instead of supplementing with melatonin, I like to recommend my clients get 15 minutes of natural light in the first hour of waking up. This stimulates the brain to make melatonin later in the day and is helpful for sleep.

Getting sunlight also implies that we are in nature, which has health benefits of its own. You can see my past blog about NatureRx.

How can we be “light deficient” in the modern world?

Indoor light is drastically different than natural sunlight. Indoor light level is about 300-500 LUX. Going outdoors, even on a cloudy day, exposes the eyes to at least 1500 LUX. A sunny day will range from 10,000-25,000 LUX.

We are meant to be exposed to the full spectrum of light that follows the rhythm of sun. Instead, we are exposed to a constant state of bright blue light from lightbulbs and screens that causes disruption to the circadian rhythm, sleep issues, low energy, vitamin D deficiency, depression, and overall low vitality.

Insufficient Sunlight & Disease Risk

The body needs sunlight in order to create vitamin D, and to prevent various diseases. Low vitamin D is linked to diseases including autism, multiple sclerosis, breast and colon cancer, heart disease, diabetes, asthma, and hypertension. Supplementing with vitamin D has not consistently been shown to prevent these conditions, which suggests there may be additional functions that sunlight provides during the synthesis of vitamin D. Sun avoidance has also been shown to be comparable to smoking with disease risk.

What about skin cancer?

Valid concerns related to excessive sun exposure include sun burns and skin cancer. In order to synthesize vitamin D, skin needs to be exposed to the sun without sunscreen. Guidelines from the Centers for Disease Control and World Health Organization advise only wearing sunscreen, avoiding sun exposure, and covering visible skin from 10am to 4pm if in the sun.

Guidelines don’t currently exist for how to optimize sun exposure to obtain the benefits, while also minimizing the risk. Dermatology guidelines similarly don’t discuss how the body needs sunlight, and are focused on preventing skin cancer. This is a valid risk, but there are ways to both get sunlight and protect from sun burns and skin cancer.

How to Optimize Light Exposure

  • Aim to get natural sunlight, without sunscreen in the early morning and late afternoon to avoid sunburn. Ideally get 15 minutes of sunlight in the first hour of waking up, as this will set the circadian rhythm and neurotransmitters for the day.
  • Take breaks throughout the day to get natural light for about 10 minutes each time. Break up screen time with short walks and moments looking out onto the horizon.
  • Remember your body needs sunlight more than screen time, so create balance.
  • Cover the face with a hat during peak sun hours, and cover your skin with light clothing to avoid sunburns. Use natural sunscreen if you’ll be out longer than 20-30 minutes and protective clothing is unavailable.
  • Build up a tolerance to sunlight by being outside prior to 10am and after 4pm, and exposing your skin for a short duration of time, taking care to avoid burning.
  • If you live in a cloudy or dark climate, I recommend full spectrum light boxes to help maintain the circadian rhythm, improve sleep, and boost mood. I am a fan of the Aurora Mini light box from Alaska Northern Lights. It’s 10,000 LUX and was an essential part of my morning routine in the dark cold months in Portland. I affiliate with them, and code DRLAURA10 saves you 10% off your order.
  • Your body needs sunlight and total darkness, so let your home get dark in the evening.
    • Turn off over head lights
    • Consider using beeswax candles
    • Switch to reddish warm light bulbs instead of bright light
    • Blue blocking glasses can be helpful if changing the environment is not possible
    • Avoid screens including phone, laptop, and TV for 1-2 hours before bed


Alfredsson L, Armstrong BK, Butterfield DA, Chowdhury R, de Gruijl FR, Feelisch M, Garland CF, Hart PH, Hoel DG, Jacobsen R, Lindqvist PG, Llewellyn DJ, Tiemeier H, Weller RB, Young AR. Insufficient Sun Exposure Has Become a Real Public Health Problem. Int J Environ Res Public Health. 2020 Jul 13;17(14):5014. doi: 10.3390/ijerph17145014. PMID: 32668607; PMCID: PMC7400257.             

Lindqvist PG, Epstein E, Nielsen K, Landin-Olsson M, Ingvar C, Olsson H. Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort. J Intern Med. 2016 Oct;280(4):375-87. doi: 10.1111/joim.12496. Epub 2016 Mar 16. PMID: 26992108.

Mead, Nathaniel. Benefits of Sunlight: A Bright Spot for Human Health. Environmental Health Perspectives. 2008 April.

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