Sauna? Ice bath? Both? What the science tells us about these recovery and health enhancing strategies.

Heat, cold, and contrast therapies can meaningfully improve short-term recovery, reduce muscle soreness, and in some cases enhance endurance and cardiovascular function.

In all walks of elite athletes, hot and cold therapy is a core recovery tool for sustaining performance under pressure. But how much of that science translates into benefits for those in other high-performance environments? The application of sports science to those individuals in these critical roles is a foundation of our approach at WellFounded. Recovery strategies that help you train hard, travel the next day, and perform at your best are valuable, but knowing how to time them to avoid blunting the gains from hours of resistance work is just as critical. Below is a brief primer on some of the core, more robust findings from recent studies looking into these strategies.

The bottom-line-up-front is that hot, cold, and contrast therapies can meaningfully improve short-term recovery, reduce muscle soreness, and in some cases enhance endurance and cardiovascular function. The benefits are, however, highly context-dependent: cold water can preserve next-day power in competition or overload weeks, but frequent post-resistance use may blunt strength and hypertrophy gains. Sauna can support vascular function, endurance, and improve cardiovascular health, with emerging evidence for mental health benefits. Contrast therapy may speed readiness when full cold is not tolerated, though evidence is limited. Timing these interventions within the training cycle, matching them to specific recovery or adaptation goals, and respecting individual cardiovascular and health risks are key to implementing these effectively.

Cold water

Cold water therapy applies a controlled thermal stress to the nervous and metabolic systems which can be leveraged to bring potential benefits (a process known as hormesis). But, for those who dread the cold water, it will be reassuring to hear that it may not be for everybody! These methods may be one tool out of many that achieve the desired outcome, be that improved recovery or mental health.

Equally also, contrary to popular depiction across social media, the temperatures used in research are not the ice-breaking viral reels, but normally a more temperate 10-15oC.

It is essential to approach cold water therapy with caution, especially for individuals with pre-existing medical conditions or those new to the practice. Women, on average, do exhibit a higher cardiovascular strain (heart rate and arterial pressure) compared to men [PMID: 36101432].

Gradual exposure to cold water, starting with short, cool showers and progressively decreasing the temperature, is recommended to allow the body to adapt safely and efficiently. Please do discuss incorporating cold water practice into your routine with a healthcare professional in advance of starting.

Muscle soreness

After a single session, cold water immersion has been shown to reduce delayed onset muscle soreness (DOMS) for up to 48 hours after intense physical activity. This may increase the time available for recovery and adaptation to occur prior to subsequent same- or next-day training sessions. Recovery enhancement is thought to be via the hydrostatic pressure and temperature effects [PMID: 33898988]. A meta-analysis in 2022 [PMID: 35157264] demonstrated that athletes who participated in cold water immersion had a significant reduction in muscle soreness after a single bout of exercise compared to those who did not. 

Resistance training

Some have been concerned that post-exercise cold water immersion may blunt the anabolic (muscle building) effects of training, especially resistance training [PMID: 31513450; PMID: 26174323]. However, while blunting of hypertrophy has been seen, some studies found there was minimal detrimental effect on strength gains [PMID: 33898988]. A recent randomised controlled trial suggested that cold water immersion following resistance training in rugby players does not blunt training adaptations [PMID: 36284024]. While a recent meta-analysis found that cold water therapy was superior to active recovery, contrast water therapy (alternating hot/cold water immersion), and warm water immersion for reduced DOMS, the effect on the recovery of strength performance was no different to active recovery [PMID: 36527593].

Cold water immersion should be considered as part of a recovery process during competitive phases, however, it should be recognised that cold water immersion may blunt training adaptations during preparation phases, particularly for resistance-based training programmes due to attenuated changes in the muscle.

Enhancing Mental Health

Single session cold water therapy has been found to have a positive impact on mental health, reducing symptoms of anxiety and depression. In one study, outdoor swimming in the UK has been noted to improve esteem, tension, anger, depression, confusion and total mood disturbance [Massey et al., 2020]. A further study found a single 20 minute immersion in cold water (13.6°C) was enough to reduce negative affect and improve vigour and esteem [Kelly & Bird, 2022]. Similar results were seen following a 5 minute immersion at 19°C [PMID: 36829490]. There is a gap in any evidence for routine cold water immersion for mental health so this approach re-emphasise that this should be on an individual experimental approach. 

Single session cold water therapy has been found to have a positive impact on mental health, reducing symptoms of anxiety and depression.

When to time in a training cycle

• Back-to-back hard days or stage racing to preserve next-day power and reduce soreness. 

• After high-intensity endurance sessions when quick 24-hour recovery matters. Shorter and colder appears more effective for reducing biomarker of muscle breakdown (creatine kinase; CK) and endurance outcomes. 

• Note: a 2025 randomised controlled trial in women found neither cold nor hot water immersion accelerated recovery from muscle-damaging exercise versus the control. Avoid assuming male-derived recovery benefits generalise to women. (PMID: 40333546)

Protocol

• 10 to 12°C, 8 to 12 min, immediately post-session (within 30-60 min, earlier is better), as needed in heavy weeks or when next-day readiness matters..

• Rationale: meta-analysis shows benefits for power, soreness, muscle damage (CK) at 24 h; dose trends favour lower temperatures and shorter durations post high-intensity work.

When to avoid

• Avoid directly after strength work if hypertrophy or strength adaptation is a goal. Chronic post-lift cooling impairs strength gains and fatigue-resistance over 8 to 12 weeks. 

• Routine daily use outside competition or overload microcycles should also be avoided, to limit potential blunting of training adaptations. In research, for endurance blocks up to ~4–6 weeks, chronic post-exercise cooling shows no clear adaptation benefit. 

(PMID: 35157264; PMID: 35254558; PMID: 35068365; Allan et al; PMID: 35873209; PMID: 32644914; PMID: 26581833)

Heat therapy

Sauna bathing is a heat-stress practice most often studied in Finnish-style dry saunas at 80 to 90°C and range from 5–20 min bouts, typically 1–3 bouts per session. Not all saunas are the same, however. Infrared units run cooler at 45 to 60°C for 15–30 min heating then rest 30 min under blankets. Most data come from Finnish-style protocols, so study findings should be treated cautiously for other formats.

As with first use of cold therapy, first use should be with caution for intensity and humidity. Typical Finnish practice uses one to three bouts of 5 to 20 minutes, with brief cooling between bouts. Longer, hotter sessions increase cardiovascular load. In healthy adults, single sessions improve vascular function and lower blood pressure acutely, but extremes of heat or rapid cold transitions add strain [PMID: 29269746]. 

Start conservatively and build up tolerance gradually. Start with shorter sessions at moderate heat, then progress if these are well tolerated. Again, please do discuss incorporating sauna practice into your routine with a healthcare professional in advance of starting, especially if you have cardiovascular disease, tendency to faint (syncope), low blood pressure, or are on medication.

Cardiovascular Health

Observational studies demonstrate that for those engaging in higher weekly sauna frequency and longer sessions there is a correlation with lower risk of cardiovascular and all-cause mortality. In Finnish men, 4 to 7 sessions per week were associated with a considerably reduced risk of sudden cardiac death, coronary disease, cardiovascular mortality, and all-cause mortality versus once-weekly use; longer session duration also tracked with lower risk [PMID: 25705824]. The same researchers reported lower incident dementia and Alzheimer’s disease with more frequent sauna use [PMID: 27932366]. Regular users also display lower risk of future high blood pressure [PMID: 28633297].

However, though the effects of sauna are in part as an exercise-mimetic, in more recent randomised controlled trials, the combination of sauna and exercise was additive to exercise alone in reducing blood pressure, cholesterol and even increasing cardiorespiratory fitness (VO2max) [PMID: 35785965].

Performance and training

Post-exercise sauna can aid endurance outcomes, as noted above, without the added mechanical load of a long training session. In competitive male runners, 30-minute sauna sessions after training, twice weekly for three weeks, increased time to exhaustion by about 32 percent; gains correlated with expanded blood volume [PMID: 16877041]. Muscle soreness and muscle recovery may also benefit from a post-session sauna [PMID: 37398966]. 

Sleep 

Anecdotal evidence suggests that 83.5% of people experience better sleep after sauna [PMID: 31126560]. Hot water bathing, however, has a greater evidence base, with a meta-analysis (summary of multiple studies) in 2019 suggesting that a hot bath at 40-42.5 °C when scheduled 1-2 h before bedtime for little as 10 min was associated with both improved self-rated sleep quality, sleep efficiency and time to fall asleep [PMID: 31102877].  

Mental health

Clinical heat protocols have antidepressant effects in small trials. Some early small randomised trials show that whole-body hyperthermia produces rapid and persistent reductions in moderate to major depression versus sham [PMID: 27172277; PMID: 28351399]. 

Observational studies demonstrate that for those engaging in higher weekly sauna frequency and longer sessions there is a correlation with lower risk of cardiovascular and all-cause mortality.

When to time in a training cycle

• Post-ride or rest-day heat exposures in base, build, or taper phase to expand plasma volume, potentiate mitochondrial adaptations and support endurance capacity without extra mechanical load. 

Protocol

• ~90°C, ~30 min, after training, 3–4 sessions/week for ~3 weeks.

• Rationale: ↑ time-to-exhaustion ~32 percent with associated ↑ plasma volume in trained runners; effect size in time-trial terms ~2%.

When to avoid

• Immediately after maximal-heat training days or if dehydrated or hypotensive.

• Replace CWI with sauna only when the goal is heat adaptation or non-inflammatory recovery support; do not combine with abrupt cold in anyone with a history of any cardiovascular concerns without medical advice due to the temperature swing caution.

(PMID: 16877041; PMID: 32644914)

Contrast therapy

Alternating cold water therapy with sauna therapy or hot water baths, also known as contrast therapy or hot-cold therapy, can also offer several benefits. This practice involves cycling between hot and cold environments, such as a sauna or a hot bath and a cold plunge pool or cold shower. 

The “best protocol” is currently elusive and anecdotal as the small available evidence uses different types of sauna and sauna protocols meaning the results can’t be extrapolated to all forms of contrast therapy. Most studies use hot-cold water baths rather than saunas; hot 38 to 40°C and cold 14 to 15°C, in 1 minute cycles for 6 to 14 minutes total, applied immediately after exercise. Sauna-with-plunge evidence is sparse and low-to-moderate quality, often without controls and focused on endocrine or haemodynamic endpoints rather than performance. The studies looking at saunas typically use a protocol of sauna bout(s) at 80–90°C then one cold-water immersion (typically 12°C for ~2 min), not minute-by-minute alternation.

The evidence to date is mainly only looking at acute effects and short-term performance benefits. The impact on long-term adaptations are not yet established.

Contrast therapy may also have a positive impact on mental health and stress reduction in the same way cold water immersion alone can. Furthermore, the relaxing effect of sauna therapy, combined with the invigorating effect of cold water therapy, can create a sense of mental and physical rejuvenation. A small study in 2022 demonstrated that in 30 men who underwent contrast sessions of 12 min at 90-91°C then 1 min in 10-11°C water, there was a significant decrease in cortisol, however there was no control group [PMID: 33845653]. 

It is essential to approach contrast therapy with caution, especially for individuals with pre-existing medical (especially cardiovascular) conditions or those new to the practice. It is advised to consult a healthcare professional before incorporating contrast therapy into your routine. Start with shorter exposure times and gradually increase the duration as your body adapts to the contrasting temperatures.

The relaxing effect of sauna therapy, combined with the invigorating effect of cold water therapy, can create a sense of mental and physical rejuvenation.

When to use

• Multi-day events or tournament-style periods where rapid same-day or next-day readiness is the priority and full cold water immersion is not tolerated. Systematic review shows better soreness and strength recovery vs passive rest, though not clearly superior to other active methods. 

Protocol

• Hot 38–40°C / Cold 14–15°C, 1-min hot : 1-min cold, total 12–14 min, start hot, immediately post-session.

• Rationale: improved subsequent cycling performance within hours in trained cyclists; dose-response work supports 6–18 min with 38.4°C/14.6°C, 1-min cycles.

When to avoid

• Immediately after strength sessions targeting hypertrophy or neural strength. Extrapolating from cooling literature, repeated post-lift cooling can blunt strength adaptations. No chronic CWT adaptation data exist. 

• As a year-round daily default; evidence supports acute recovery vs passive rest but not superiority over other modalities for recovery across the evidence base. 

(PMID: 20809231; PMID: 23626806; PMID: 35254558)

Heat, cold and contrast therapy considerations.

Further Reading

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Allan, R., Akin, B., Sinclair, J. et al. Athlete, coach and practitioner knowledge and perceptions of post-exercise cold-water immersion for recovery: a qualitative and quantitative exploration. Sport Sci Health 18, 699–713 (2022). https://doi.org/10.1007/s11332-021-00839-3

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Fyfe JJ, Broatch JR, Trewin AJ, Hanson ED, Argus CK, Garnham AP, Halson SL, Polman RC, Bishop DJ, Petersen AC. Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. J Appl Physiol (1985). 2019 Nov 1;127(5):1403-1418. doi: 10.1152/japplphysiol.00127.2019. Epub 2019 Sep 12. PMID: 31513450.

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