The first time I committed to regular cold immersion I lasted about forty-five seconds. It was 10°C and I thought I was going to die. Six months later I was doing ten minutes at 34–50°F without flinching, studies show testosterone increases with consistent cold exposure, my recovery between sessions was measurably faster, and I was calmer under pressure both on and off the mats than I'd been in years. The cold changed more than my body temperature.
Cold water immersion has one of the strongest evidence bases of any recovery modality. The research spans testosterone, growth hormone, inflammation markers, fat metabolism, cardiovascular adaptation, and — perhaps most interesting to combat athletes — the neuroscience of voluntary discomfort.
This is the full breakdown of why I ice bath, what the science actually says, and exactly how I structure it around BJJ training five to seven times per week.
Cold Immersion and Testosterone
Cold exposure activates the hypothalamic-pituitary-gonadal (HPG) axis — the hormonal cascade responsible for testosterone production. Simultaneously, it is one of the most effective interventions for reducing cortisol, which is the primary suppressor of testosterone at the tissue level.
Cold stress triggers norepinephrine release, which stimulates GnRH from the hypothalamus, cascading through LH release from the pituitary to testosterone production in the testes. Consistent cold exposure studies show 10–30% increases in circulating testosterone in men over a 12-week protocol.
Cortisol and testosterone operate in opposition. Cortisol chronically suppresses Leydig cell function — reducing testosterone synthesis directly. Cold immersion acutely lowers cortisol, creating a hormonal environment more conducive to testosterone expression and anabolic recovery.
Sex hormone binding globulin binds testosterone, rendering it inactive. Cold exposure reduces SHBG levels, increasing the proportion of free — biologically active — testosterone available to muscle tissue and the brain.
Mooventhan A & Nivethitha L (2014) — Scientific Evidence-Based Effects of Hydrotherapy on Various Systems of the Body. North American Journal of Medical Sciences.
Pre-Cooling for Performance
Pre-workout cold immersion reduces core body temperature and delays the onset of heat fatigue during high-intensity work. For a grappler drilling and sparring in a humid gym, this is a meaningful performance advantage. The duration and temperature of your pre-cool depends on your plunge setup. At 34–40°F (the range most serious practitioners run), 3–4 minutes approximately one hour before training is the target — this is enough to meaningfully lower core temperature without inducing the fatigue or vasoconstriction that comes from longer exposure at that temperature. The 10–15 minute recommendations you will see elsewhere are calibrated for warmer settings around 50°F. If your plunge is colder, your time in comes down accordingly.
- Pre-cooling: 3–4 min at 34–40°F approximately 1 hour before training (at warmer settings ~50°F, 10–15 min is appropriate — match duration to temperature)
- Recovery immersion: 2–10 min post-training — wait 4+ hours after strength work to preserve hypertrophy stimulus
- Frequency: 3–4x per week minimum for systemic hormonal benefits
- Temperature: 34–50°F — below this range risks peripheral vasoconstriction sufficient to impair recovery rather than enhance it
Multiple peer-reviewed studies have demonstrated up to a 19% improvement in high-intensity exercise output in pre-cooled athletes versus controls. The mechanism is straightforward: a lower core temperature at the start of exercise means the body takes longer to reach the thermal threshold at which performance degrades. More rounds. Better quality in the later rounds.
Brown Fat, Inflammation, and Resilience
Regular cold exposure activates and grows brown adipose tissue deposits — metabolically active fat that burns white fat for thermogenesis. More brown fat means a higher resting metabolic rate, better glucose regulation, and improved thermoregulation capacity.
BAT contains mitochondria rich in uncoupling protein 1 (UCP1), which dissipates energy as heat rather than ATP. Cold activates BAT, and consistent cold exposure grows BAT deposits — improving metabolic efficiency and insulin sensitivity in parallel.
Cold immersion consistently reduces IL-6, TNF-alpha, and CRP — three primary markers of systemic inflammation. For midlife grapplers training 4–5x per week, managing these markers is the difference between sustainable adaptation and chronic tissue breakdown.
Voluntary cold immersion — choosing to enter discomfort and stay calm — actively trains the prefrontal cortex to override primal discomfort signals. This neural adaptation transfers directly to the mats: you get better at staying calm under pressure, in bad positions, in the final minute of a hard round.
van Marken Lichtenbelt WD et al. (2009) — Cold-Activated Brown Adipose Tissue in Healthy Men. New England Journal of Medicine.
Bleakley C et al. (2012) — Cold-Water Immersion and Recovery from Strenuous Exercise. British Journal of Sports Medicine.
The discipline of cold carries directly onto the mats. You don't just recover faster — you learn to stay calm under pressure.
— 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.
