I get up early. Not because I enjoy 5am — I don't. I do it because the first thing I do after waking sets the tone for everything: testosterone timing, cortisol curve, melatonin onset that night, and the metabolic state that determines how I perform in the evening session. The tool is free, it takes twenty minutes, and it is the most evidence-backed thing I do every single day. It's morning sunlight.
Modern health culture has made the sun the enemy. Dermatologists recommend year-round SPF 50. Social media is full of warnings about UV exposure. Meanwhile, Vitamin D deficiency affects an estimated 42% of the US population, rates of depression, autoimmune disease, and metabolic dysfunction are accelerating, and the epidemiology of melanoma does not match the narrative we've been sold.
The sun did not become dangerous. We became disconnected from it. This post is the full breakdown of morning sunlight: the circadian science, the Vitamin D mechanism, the sunscreen truth, and what natural protection actually looks like.
Morning Light and the Circadian Clock
Light entering the retina in the morning directly stimulates the suprachiasmatic nucleus (SCN) — the master circadian clock in the hypothalamus. This signal sets the timing of every hormonal release, metabolic process, and sleep-wake transition that follows for the next 24 hours.
- 10–20 minutes of outdoor sunlight within 30 minutes of waking
- No sunglasses — the photoreceptors involved in circadian signalling are in the peripheral retina and require unfiltered light
- Face toward the sun — not looking directly at it, but facing the direction of solar radiation
- Even on overcast days — cloud cover reduces light intensity but does not eliminate the circadian signal
Morning light exposure determines when melatonin production begins that night — typically 14–16 hours after the morning light signal. Consistent morning sun at the same time each day produces consistent, predictable melatonin onset. This is why athletes who get morning sun sleep better than those who don't — even if their total light exposure is equivalent.
The cortisol awakening response (CAR) is a natural spike in cortisol within 30–45 minutes of waking that primes the body for alertness, focus, and physical readiness. Morning sunlight amplifies and sharpens the CAR — producing a cleaner energy curve throughout the day without the crash associated with caffeine-driven cortisol stimulation.
Testosterone is highest in the morning and follows circadian patterning. Consistent circadian anchoring through morning light exposure produces more consistent testosterone peaks — optimising the hormonal environment for morning training sessions.
Vitamin D: Steroid Hormone, Not Just a Vitamin
Vitamin D3 — synthesised from cholesterol in skin exposed to UVB radiation — is technically a steroid hormone, not a vitamin. It activates receptors in virtually every cell in the human body and regulates over 2,000 genes. Optimal levels are associated with testosterone production, immune competency, bone density, mood regulation, and reduced all-cause mortality.
Optimal Vitamin D levels for performance and health sit between 60–80 ng/mL. The majority of office workers, sunscreen users, and those living at northern latitudes are well below 30 ng/mL. This is a public health crisis disguised as a sunscreen success story.
Pilz S et al. (2011) — Effect of Vitamin D Supplementation on Testosterone Levels in Men. Hormone and Metabolic Research.
The Sunscreen Problem and Natural Alternatives
The most commonly used chemical sunscreen ingredients — oxybenzone, octinoxate, and avobenzone — are classified as endocrine disruptors. They are absorbed transdermally within 30 minutes of application and have been detected in blood, breast milk, and urine at concentrations that exceed FDA safety thresholds.
Oxybenzone mimics oestrogen in the body and has been shown to reduce testosterone in male subjects. For a midlife athlete already managing hormonal decline, applying a hormone-disrupting chemical to large skin surface areas daily is counterproductive to every hormonal optimisation effort.
Zinc oxide (non-nano) and titanium dioxide are the only two sunscreen ingredients the FDA currently considers safe and effective. For extended unavoidable sun exposure: zinc oxide-based formulas, red raspberry seed oil (natural SPF 28–50), carrot seed oil (SPF 35–40), and shea butter provide protection without hormonal disruption.
My position is simple: seek appropriate sun exposure for your skin tone, build melanin gradually, avoid burning, and use shade before chemicals. The melanoma narrative is more complex than 'sun = cancer' — and the data on Vitamin D deficiency, which sunscreen directly causes, is damning.
We evolved under direct sunlight for 200,000 years. The melanoma spike aligns with sunscreen adoption — not increased sun exposure. Avoidance is the disease.
— Josh Button · @thatjiujiteiroThe Bottom Line
This didn't come from a textbook or a coach handing me a protocol. It came from years of training hard, getting injured, burning out, and rebuilding — smarter every time. Everything in this post is something I do, have done, or have researched deeply enough to stake my performance on.
Start with one thing. Implement it fully. Then add the next. The compounding effect of doing the basics with precision beats any biohack or supplement stack.
Hard to Kill isn't a slogan. It's the standard.
Stay Dangerous. Stay on the Mats. Hard to Kill in Midlife.
