Every week our coaches at Peak Fitness in Orem read the actual studies behind a popular training or nutrition claim and boil them down to what holds up and what to do with it. Here's No. 03.
The real benefits
- Mood: an hour in 57°F water raised dopamine 250% and noradrenaline 530% (one small study, much longer than a normal plunge).
- Stress dropped 12 hours after cold immersion in a 2025 review of 11 trials.
- 30–90 second cold showers for 30 days led to 29% fewer sick days in 3,018 adults.
- Less muscle soreness for up to 4 days after hard training.
The one bad time: right after lifting
- Across 8 studies, plunging right after lifting blunted muscle growth. The effect is small, but it keeps showing up.
Hype check
- Brown fat is real, but no study shows plunging melts fat.
- No human study links cold plunging to a longer life.
- Palm cooling between sets (the Stanford research) looked big in the original studies, but independent tests mostly have not reproduced it.
The protocol
- →Rest days, cardio days and race week: 10–15 minutes in 41–59°F water.
- →Building muscle? Keep it off your lift days.
- →Doing cardio in the heat? Cooling down before you start improved endurance across 15 trials.
Not medical advice. Heart condition or high blood pressure? Talk to your doctor before you cold plunge.
Sources
- Cain et al. Effects of cold-water immersion on health and wellbeing: a systematic review and meta-analysis. PLOS ONE, 2025
- Šrámek et al. Human physiological responses to immersion into water of different temperatures. Eur J Appl Physiol, 2000
- Piñero et al. Throwing cold water on muscle growth: post-exercise cold water immersion and resistance training-induced hypertrophy. Eur J Sport Sci, 2024
- Roberts et al. Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. J Physiol, 2015
- Berjisian et al. Strategic application of post-exercise cold-water immersion: an umbrella review. Sports Med Open, 2026
- Yu et al. Effects of precooling on endurance exercise performance in the heat. Nutrients, 2024
- Søberg et al. Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in winter-swimming men. Cell Rep Med, 2021
- Grahn et al. Work volume and strength training responses to resistive exercise improve with periodic heat extraction from the palm. J Strength Cond Res, 2012