Direct outdoor sunlight exposure — especially during sunrise and sunset—is central to optimal health, healing, and prevention of chronic disease.

Your physiology, hormones and metabolism depend on sunlight to function optimally.

For example, when sunlight hits your retina (located in your eye) when viewing early morning sunlight, this triggers a cascade of reactions in your body that regulate hormone and neurotransmitter signaling:

• It triggers a spike in early-day cortisol release, which is optimal for wakefulness, immune function, metabolism, and focus. This timing is crucial: cortisol should spike early for health, not later in the day.
• It sets in motion a dopamine-related cascade in neuromodulators, dopamine, and hormones that lead to states of wellbeing, elevated mood, alertness, etc. throughout the day.
• It reinforces our circadian rhythm, which indirectly supports everything from hormone production to immune response, hunger regulation, body temperature control, and even mental health.
• It helps your body produce melatonin later in the evening, optimizing sleep quality.
• It regulates appetite and hunger hormones, reducing the feeling of constant hunger and potentially leading to weight loss and improved body composition.

Sunlight at Different Times of the Day

In addition to early morning sunlight, sunlight exposure at different times throughout the day provides unique health benefits due to the different frequencies of light present at different times of the day. For example:

• Sunrise – UV light is absent. Sunlight spectrum is mostly infrared with modest amounts of blue light. It triggers the release of cortisol and optimizes energy production in the cells. It helps regulate neurotransmitters like dopamine and serotonin, and has positive effects on alertness, mood, and cognition. It also helps prevent sunburn later in the day by preconditioning the skin.
• Late morning – UV-A is the predominant light. UV-A light activates and replenishes stores of dopamine, serotonin and melatonin. It also triggers cellular repair and preprograms the skin to absorb UV-B later in the day, reducing your risk of sunburn [8].
• Midday – UV-B index is highest. Be careful not to burn – UV-B light stimulates vitamin D production, lowers blood pressure, speeds up metabolism, improves thyroid function, rebuilds and restores hormone levels, improves carbohydrate metabolism, diversifies the gut microbiome, and boosts dopamine, serotonin, and beta-endorphins.
• Sunset – Predominant light is red light. Stimulates healing mechanisms in the mitochondria, recycles hormones, and reinforces circadian rhythm.

Overall Benefits

Sun exposure uniquely benefits our body by:

• Supporting immune cells and inflammation, independent of Vitamin D production, by increasing the movement of T cells, helping them reach infection sites more efficiently.
• Regulating hormones such as melatonin and cortisol, which are crucial for sleep, mood, and stress management.
• Proper signaling to the brain to release and regulate neurotransmitters like dopamine and serotonin.
• Increasing energy at the cellular level, supporting better overall energy and vitality.
• Increasing the number of beneficial bacteria in our gut, producing better digestion and gut function and improving overall health outcomes.
• Stimulating the production of vitamin D in the skin, which is essential for immunity, bone strength, and disease prevention.
• Synchronizing the body’s circadian rhythm (our internal clock), supporting sleep quality and metabolic health.
• Ultraviolet (UV) light exposure has been shown in animal studies to decrease leptin levels in subcutaneous fat while increasing energy expenditure by promoting “browning” of fat, which helps prevent weight gain even with increased appetite.
• Sunlight, particularly morning light exposure, appears to have a significant influence on leptin, the hormone responsible for regulating appetite and energy balance. Research shows that exposure to natural light or specific wavelengths of light in the morning can increase leptin levels, which helps reduce hunger.

Sunlight as Therapy

Sunlight is so good at improving our body’s ability to heal, in fact, that:

• Sunbathing and sunlight therapy was used in the past as an effective treatment for many infectious and chronic diseases. Solariums (sun hospitals) existed in various parts of the world where the sick and diseased could come to be healed.
• For example, sunlight therapy – also known as heliotherapy – was used in the early 20th century and during World War I to treat a variety of conditions including infectious disease, wound healing, anemia, high blood pressure, rickets, bone disease, autoimmunity, digestive issues, asthma, migraines, cancer, hormonal imbalances, and infertility.
• Sunlight therapy was also used to treat conditions like depression, neurasthenia (chronic fatigue), and general debility, especially in the 19th and early 20th centuries.
• This likely happened because sunlight exposure boosts serotonin levels, improving mood, and supports circadian rhythm regulation, enhancing sleep and energy. It was also believed to invigorate the body holistically.
• Sanatoriums and health resorts promoted heliotherapy for “nervous disorders” and to restore vitality in urban populations with limited sun exposure.
• Sunlight expert and author of The Sunlight Rx, Heathar Shepard, uses a sunlight exposure protocol to assist in eliminating chronic health issues in her clients with great success. She discovered this protocol after using sunlight therapy to heal debilitating symptoms from a TBI that persisted for a decade while no other treatment or lifestyle intervention worked.

The Problem

Most people don’t get enough sunlight.

In fact:

• Americans now spend 90% of their time indoors [1]. This is having a huge negative impact on our immune system, our brain chemistry, and our hormones.
• This is the main reason that around 22-40% of Americans are deficient in vitamin D [2].
• In addition, most people nowadays have dysregulated circadian rhythms due to being exposed to light frequencies throughout the day that are inconsistent with the sunlight outside.
• Said another way, most people aren’t taking the time to expose themselves to sunlight at different times throughout the day in order for the body to get the proper signaling it needs to know what time of day it is.
• In addition to that, we are being exposed to indoor artificial LED lighting that is continuously signaling to our body that it is 12pm (noon) all day long, due to the high blue light content of LED lighting.
• This is especially problematic if we are exposing ourselves to artificial lights after sunset, when are body needs to be getting the signal that it’s almost time for bed.
• We know that disruption in our circadian rhythm is linked to a host of health issues including reduced dopamine signaling, mental health issues, sleep disorders, insulin resistance, metabolic syndrome, weakened immunity, disrupted hormones, premature aging, and even certain cancers as indicated by the WHO [3].

For most of human history we spent the majority of our time outdoors hunting, gathering, farming, working, etc.

Modern living has brought us indoors under artificial lighting for most of our day, causing us to miss out on constant mood-boosting, immune-regulating, energy-generating input from the sun.

In order to improve our health, we have to make an effort to get more exposure to sunlight at different times throughout the day as well as eliminate or reduce our exposure to artificial light after sunset.

Isn’t Sunlight Harmful?

Sunlight has been vilified as this scary thing that causes skin cancer that we should avoid at all costs.

Although I agree that getting sunburnt is unhealthy, the notion that we should lather our bodies in toxic chemicals to block the sun every time we go outside is complete non-sense in my opinion.

Humans have been exposed to sunlight for all of human history. Our bodies need sun exposure to function optimally, and way more of it than what we’ve been led to believe.

Here are some issues I have with all the anti-sunlight rhetoric pushed by the government and medical establishments:

• Most studies investigating the link between UV light and skin cancer are conducted inside using artificial UV-B light bulbs, not actual sunlight. These studies also fail to precondition the skin with redlight.
• Real sunlight contains the entire light spectrum, which is much different than artificial UV light used in isolation.
• The high amount of infrared light present at sunrise and sunset is thought to precondition the skin for UV light later in the day [4].
• Scientific studies don’t take these things into account.
• Since the introduction of sunscreen in the early 1970’s, rates of skin cancer have risen 4% per year and continue to do so [5][6].
• Even though sunscreen usage has increased, rates of cancers like melanoma and nonmelanoma have also increased, not decreased [5][6].
• Sunscreen doesn’t protect against melanoma [7].
• The more technologically advanced the world becomes, the less people go outside and the more time people spend inside exposing themselves to artificial lighting through screens and overhead LEDs. Yet, skin cancer rates are rising, not decreasing.
• The skin cancer diagnostics market is projected to be $5.4 billion annually by 2028 [10].
• The skin cancer treatment market is projected to be $14.55 billion by 2027 [9].
• This massive profit off skin cancer makes me extremely skeptical of receiving advice from medical and government officials who are being incentivized to diagnose and treat, rather than research the root cause and recommend steps for prevention.
• Finally, I happen to believe in the philosophical argument that man’s intervention, not nature, causes disease.

Our personal recommendation

Spending more time in the sun at specific times throughout the day – at sunrise, at early morning, midday, and at sunset – is the single most effective practice to help boost hormone, metabolic, immune and gut health as it helps your body naturally restore and produce the chemicals, hormones and signaling your body needs to heal and be healthy.

Of course we live in the real world and understand not everyone can spend time outside whenever they feel like it. My wife and I work office jobs ourselves.

For those with office jobs or demanding schedules, we recommend aiming for three 15-minute walks per day, once in the morning, once at midday, and once in the afternoon/sunset in order to keep your circadian rhythm in sync.

For optimal health we recommend the following:

1. View the sunrise – The sun needs to be just coming over the horizon. View it directly for several seconds before adjusting your gaze about 30-45 degrees downward, ensuring some light is entering your peripherals. You never want to look directly at the sun, with the exception of the first minute or so of sunrise.
2. Expose your skin to morning sunlight – From about 6am – 8am, get as naked as possible (while keeping it legal) and let the sun shine on as much of your exposed body as possible for 15 minutes – 2 hours. While this amount of time may not be practical for everyone, even a few minutes is beneficial.
3. Expose your skin to late morning sunlight – From about 8am – 10am, try to get at least 15 minutes – 2 hours of sunlight exposure on as much of your body as possible.
4. Sunbathe at noon – 11am – 2pm. Your skin type and melanin levels will dictate the amount of time you should stay out in the sun at this time of day when UV-B light is present and the risk of sunburn is high. Try to aim for at least 15 minutes to one hour depending on several factors like skin type, your geographic location, and the current season. Preconditioning your skin with UV-A from morning light will help protect your skin, but always be cognizant of if your skin is starting to burn. Use clothes or non-toxic sunscreen to protect your skin once you’ve gotten your dose.
5. Avoid Sunburn – Although I’m skeptical that sunburn alone causes skin cancer, I still think it’s a bad idea to get burned by the sun. UV-B damage on your skin causes pre-mature skin aging in addition to being very painful. Please try to use non-toxic sunscreen or put on more clothes to avoid overexposure to UV-B light during the middle of the day.
6. Watch the sunset – This will relax your nervous system, producing feelings of tranquility and preparing your body for sleep. The redlight present during sunset will synchronize your circadian rhythm and help heal damage to the skin from UV-B during the day.
7. Avoid artificial lights after sunset – Exposure to artificial lights after sunset is undoing all the work you did throughout the day trying to reinforce your circadian rhythm with intermittent sun exposure. Artificial lights after sunset are a bad idea as they are signaling to your body that it’s midday, suppressing melatonin production and impacting your health over the long term. There is scientific evidence showing that artificial light exposure at night leads to lower dopamine levels and negative mood outcomes the next day, independent of circadian rhythm disruption [11][12]. Instead, if you need light, use dimmable lights with warmer colors. Red light is best. We use Himalayan salt lamps along with these lights.
8. Wear circadian rhythm harmonizing glasses – We recommend wearing some form of blue light blocking or circadian rhythm harmonizing glasses whenever you are being exposed to artificial lighting, particularly after sunset. This is a good way to protect your circadian rhythm. We personally use this brand.

How to Determine How Much Midday Sun Exposure You Need

Not everyone will need the same amount of sun exposure at midday to receive benefits. It all depends on a few factors like:

• Your Fitzpatrick skin type – Those with lighter skin tones will need less sun than those with darker skin tones.
• Your geographic location – As you move closer to the equator, the UV index tends to increase.
• The current season – There is more UV-B light during the summer than any other season.

For example, someone with a light skin tone in south Florida at noon during the summer will need way less time in the sun than someone with a darker skin tone on a cloudy winter day in Iceland.

Use your best judgement. If you feel your skin getting hot and starting to burn, first take note of how many minutes it took for that to start, then proceed to apply some non-toxic sunscreen or put on more clothes to avoid sun damage.