Many jiu-jitsu practitioners just reach straight for ice following a gruelling training session. But what if that instinct is doing the opposite of what you really want?
Recent research suggests that the old ritual of the ice bath may be not only overrated but in cases of strength training counter-productive. The novel 2025 study titled “Post-exercise home-based hot-bathing with/without light exercise: effects on physiological adaptations to short-term high-intensity resistance training in healthy young men” (Takeda et al.) signals a serious rethink: heating might edge out cooling when the goal is strength adaptation.
In that study, healthy young men completed five sessions of isometric knee-extension training at 75 % of maximal voluntary contraction (MVC) over two weeks. They were split into four groups: shower only; hot-bathing at 40 °C; hot-bathing plus light exercise; and shower plus light exercise. The hot-bathing group delivered significantly greater MVC gains (effect size d = 0.92 vs d = 0.36 for shower).
Moreover, hot-bathing mitigated the drop in electrically evoked tetanus torque, indicating reduced peripheral fatigue. Voluntary activation (a proxy for central nervous system drive) remained unchanged across groups, and adding light exercise offered no extra benefit—indeed, light exercise without hot-bathing decreased voluntary activation (p = 0.021). In plain terms: post-exercise heating boosted strength adaptation; adding a light movement post-bath didn’t help; doing light movement without the bath may even harm neural drive.
Why does this matter? Because for anyone chasing real strength from resistance training, adaptation (not just soreness relief) is the endgame. And yet, ice baths dominate influencer culture. That needs scrutiny.
If you dig beyond that single study, the picture gets more interesting and a little messy. A 2017 paper in The Journal of Physiology found that skeletal muscle recovery from fatigue-inducing endurance work was impaired by cooling (muscle temperature ~16-26 °C) and improved by heating (~36 °C) — mechanisms: impaired glycogen resynthesis and slower force recovery when cold. A broad 2021 network meta-analysis of 59 trials (1,367 patients) concluded that hot-pack application within 24 h after exercise ranked top for pain relief; cold immersion did better only beyond 48 h. Meanwhile, a 2015 study in the Journal of Strength & Conditioning Research comparing cold and heat for leg-squat stress found both modalities reduced strength loss (from 24 % down to ~4 %) when applied immediately, but cold applied 24 h later fared better than heat at that delayed point. And a recent review (2023) exploring cooling vs heating for resistance, endurance and sprint exercise flags a key issue: chronic cooling (regular ice baths used every session) can impair strength gains and neuromuscular adaptation particularly in resistance-training contexts. Heating shows promise, but the data are limited.
In short: immediate cooling might help feel better or reduce soreness, but when you care about strength adaptation and neuromuscular function, cooling after training may be sub-optimal whereas heating may be under-utilised.
Think of training as the process of breaking down muscle fibres and stressing the central and peripheral systems; the recovery period is when adaptation happens. When you flood your muscles and the surrounding tissue with heat after training, blood flow increases, delivery of nutrients improves, metabolic reactions speed up, and muscle temperature stays elevated. The recent Takeda study suggests that this state after a high-intensity resistance session allows the nervous-muscular system to recover more fully or less impeded so that the next session hits harder in an adaptive way.
Contrast that with cold: it constricts blood vessels, slows metabolism, and may dampen the inflammatory and metabolic signals that drive adaptation. Another thread of evidence suggests cooling after resistance training lowers microvascular perfusion and blunts amino-acid incorporation into muscles.
In other words: when you cool immediately after a session you may be short-circuiting the very adaptations you’re chasing.
If you train for strength (not just “feel better”), then the standard ice bath ritual deserves questioning. After a hard, heavy session you might gain more by hopping into a 15–20 minute hot shower or bath at around 40 °C than plunging into ice or cold water. The specific study by Takeda et al. used a 40 °C bath in a home-based setting and still got the effect.
You don’t need to haul a cryo-chamber; you just need to avoid rushing into cold immersion after your work. That doesn’t mean cold is useless—if your goal is acute pain relief or cooling after endurance sessions in the heat, it still has a role. But when it comes to building strength and neuromuscular adaptation, heat might be the smarter recovery bet.
This isn’t a blanket recommendation to ditch cold therapy forever. A few cautions:
The Takeda study spanned two weeks with isometric knee-training in healthy young men. Extrapolating to all populations (women, older athletes, endurance athletes) demands care.
Immediate hot exposure after training may carry cardiovascular implications: your heart rate and blood vessels are already in a stressed, dilated state; going into a very hot bath or shower immediately may risk dizziness or hypotension—give yourself a 5-10 minute transition period.
If you have injuries, inflammation, or a specific clinical scenario, cold may still be preferred.
“Hot” doesn’t mean scalding: the optimal dose and timing for heating are still under-researched. Another meta-analysis suggests 41-44 °C for 40-45 minutes showed benefits, but practical home baths may vary.
The mantra “ice is nice” may be losing its shine. If your aim is to build strength, improve neuromuscular adaptation and make each training session count, a hot shower or bath after your workout might be the under-used tip you’ve ignored. The data tell us: heat helps strength gains, reduces peripheral fatigue; cold might feel good and reduce soreness, but it may blunt your gains if used too aggressively post-resistance training.
So next time you finish a heavy session, skip the ice tub, dial the water heater up, step into a warm stream of water and let your muscles recover for real.
References
Takeda, R., Sumura, K., Nishikawa, T., & Watanabe, K. (2025). Post-exercise home-based hot-bathing with/without light exercise: effects on physiological adaptations to short-term high-intensity resistance training in healthy young men. European Journal of Applied Physiology. Published 15 October 2025.
Petrofsky, J. S., Khowailed, I. A., Lee, H., Berk, L., Bains, G. S., Akerkar, S., Shah, J., Al-Dabbak, F., & Laymon, M. S. (2015). Cold vs. heat after exercise – is there a clear winner for muscle soreness? Journal of Strength & Conditioning Research, 29(11), 3245-3252.
Murphy, S. L., et al. (2017). Post-exercise recovery of contractile function and endurance in humans and mice is accelerated by heating and slowed by cooling skeletal muscle. The Journal of Physiology.
Heled, Y., et al. (2021). Effect of cold and heat therapies on pain relief in patients with delayed onset muscle soreness: A network meta-analysis. Sports Medicine.
