Craving the Sun: Our Natural Addiction to Sunlight
Living in Miami gives me a head start on sun exposure, and I’ve elevated sun to the top of my health routine. I would prioritize sun over exercise, except that my 5 am workouts eliminate any conflicts. I strive for at least 90 minutes of sun per day: morning sun as close to sunrise as my family schedule permits; lunchtime outside; and whatever breaks I can find between work meetings or other downtime.
Sun trailblazer Dr. Jack Kruse has illuminated a remarkable chemical reaction that occurs when sunlight hits our eyes and skin:
- POMC: UV light boosts our bodies’ production of a protein in the pituitary gland, skin, and immune system called POMC.
- POMC cleavage: UV exposure increases the rate at which enzymes cut POMC into smaller, specialized molecules.
- Beta-endorphin: One molecule created from the cleavage of POMC is beta-endorphin, a neurotransmitter known for relieving pain and enhancing mood. Beta-endorphin is the most studied and most potent of the endorphin hormones.
In summary, getting sun on your skin really does feel good, and your biology is trying to make you hooked on sunlight.
In fact — as nature intended — I’ve developed an addiction to the sun. When I’m travelling for work or stuck at my computer, I have genuine withdrawal symptoms:
- Fatigue
- Anxiety
- Irritability
- Difficulty concentrating
- A strong urge to use the substance again
My addiction hasn’t yet caused me to discard my personal or professional obligations. In fact, I urge my family to join me at the pool on the weekends (my 7-year-old is usually game), and I’d be thrilled if we ate our meals together on the balcony. Furthermore, instead of hiding my behavior from those closest to me, I tell them to their face: sitting in the house staring at your blue-lit screens is terrible for your health.
Interestingly, the cleavage of POMC by UV light also creates a molecule called alpha-MSH stimulating hormone. Alpha-MSH boosts production of melanin (skin pigmentation), which acts as a defense against UV damage. The more you’re exposed to UV light, the greater your skin protection.
Recently I’ve been experimenting with shade. It’s an opportunity to multitask outside, as well as extend the amount of time I spend in natural light. Due to UV scattering, these rays reach me even when I’m not exposed directly to sunlight. In addition, outdoor brightness is orders of magnitude greater than inside; studies show that bright days reduce the circadian disruption from artificial light at night.
For our ancestors, direct sun exposure would have been incidental to their daily activities. No caveman was lounging at the pool. Bright days, however, would have been a way of life.