Cold water immersion — ice baths, cold plunges, contrast bathing — has moved from elite sports recovery rooms into mainstream fitness culture with remarkable speed. The research on what cold exposure actually does is more nuanced than the marketing around it suggests, and the answer differs meaningfully depending on what kind of training you do and what outcome you’re prioritizing.
What cold water immersion does acutely
The short-term effects of cold water immersion (CWI) are reasonably well-established. Immersion in cold water (typically 10 to 15°C) constricts blood vessels, reduces blood flow to the immersed tissue, decreases nerve conduction velocity, reduces tissue temperature, and attenuates the inflammatory and metabolic response to exercise. The subjective experience — reduced muscle soreness and a sense of physical recovery — is consistent across studies. Whether this reflects genuine tissue recovery or primarily a perceptual effect is one of the more contested questions in the literature.
A 2025 network meta-analysis covering 55 randomized controlled trials found that CWI reduces delayed onset muscle soreness (DOMS) and creatine kinase levels (a marker of muscle damage) after exercise. Medium-temperature CWI (11 to 15°C for 10 to 15 minutes) appeared to offer the best balance between cooling effect and practical comfort, outperforming lower temperatures on most recovery markers. The evidence for jump performance recovery was also positive, suggesting short-term functional recovery is a genuine outcome rather than purely perceptual.
The hypertrophy problem
Here is where the research complicates the picture significantly. The inflammatory response to resistance training — the same process CWI suppresses — is also part of the signaling cascade that drives muscle adaptation. By blunting post-exercise inflammation, cold immersion may be interfering with the very mechanism that makes strength training produce muscle growth.
A 2024 systematic review and meta-analysis in the European Journal of Sport Science found that post-exercise CWI likely attenuates resistance training-induced hypertrophy compared to resistance training alone, though the effect does not completely prevent gains. Multiple earlier studies by Roberts and colleagues and Fyfe and colleagues found that CWI reduced type II muscle fiber hypertrophy and attenuated anabolic signaling after resistance training. A 2025 study at Maastricht University confirmed that CWI significantly reduces blood flow to muscles post-exercise, hindering protein absorption critical for muscle repair.
The strength picture is somewhat different. Some studies show attenuated strength development with chronic post-exercise CWI; others do not. The meta-analysis found mixed evidence, with some suggestion that strength gains may be less affected than hypertrophy — though one landmark study by Roberts and colleagues found meaningful reductions in leg press and knee extension strength gains after 12 weeks of resistance training with CWI applied after each session.
Cold exposure and endurance training
The picture for endurance training is more favorable. Multiple reviews have found little or no negative effect of post-exercise CWI on endurance adaptations, and some evidence suggests it may support recovery between high-volume endurance sessions by reducing acute fatigue and allowing higher training quality in subsequent sessions. This makes intuitive sense: the signaling pathways for endurance adaptation (mitochondrial biogenesis, cardiovascular adaptation) are less dependent on the acute inflammatory response that CWI suppresses.
For athletes doing high-volume endurance sport — particularly in multi-day competition or heavy training blocks where managing cumulative fatigue matters more than maximizing any single adaptation — CWI has a more consistent evidence base for usefulness.
Cold exposure beyond exercise recovery
Cold water immersion has been studied for effects beyond exercise recovery, including mood, alertness, and stress regulation. A 2025 review of studies on CWI and health and wellbeing found some evidence for improvements in self-reported mood, alertness, and stress. The quality of these studies is variable, and most used healthy adults rather than clinical populations, limiting generalizability. The Wim Hof Method — a specific protocol combining cold exposure with breathing techniques — has some evidence for effects on inflammation markers, but a 2024 systematic review concluded the quality of existing studies is low, with small sample sizes and strong male bias, making definitive claims premature.
What the 2025 PLOS ONE trial on women found
A 2025 randomized controlled trial published in PLOS ONE found that neither cold nor hot water immersion accelerated recovery from exercise-induced muscle damage in women. This adds to a small but growing literature suggesting that sex differences in thermoregulation, hormonal environment, and muscle physiology may produce different responses to temperature-based recovery than those observed in predominantly male study populations. The research here is early and the evidence base for sex-specific protocols is thin, but it is a legitimate caveat on applying male-population findings universally.
When to use cold exposure and when to avoid it
The practical framework that emerges from this research is goal-dependent. If you are in a heavy endurance training block, or in competition preparation where managing fatigue across days matters more than maximizing long-term adaptation, post-exercise CWI has evidence behind it. If your primary goal is building muscle mass or maximizing strength development from a resistance training program, the evidence that post-exercise CWI attenuates the very adaptations you’re training for is strong enough to argue against using it routinely after lifting sessions.
The timing matters too. CWI applied several hours after a resistance training session — rather than immediately after — may reduce the interference with anabolic signaling, though the evidence on this is still developing. Cold exposure at times unrelated to training, or before rather than after sessions, is a different question from the post-exercise application that the bulk of the research has examined.
The wellness and mood benefits of cold exposure — reported subjective improvements in energy and alertness — may have value independent of exercise recovery. Whether they are robust enough to justify the practice for non-athletes is a question the current evidence cannot fully answer. What can be said is that the evidence for cold exposure as a blanket recovery enhancer is considerably weaker than its popularity suggests.