Of the eight studies in the most cited meta-analysis on cold water immersion and muscle recovery, just one included a single female participant. Across the broader research base, a 2026 network meta-analysis found that 85 per cent of all CWI protocol research has been conducted on men. If you are a woman who has ever searched for “ice bath women” and read about the benefits of cold plunging, you were almost certainly reading conclusions drawn from male bodies, presented as though they applied to everyone.
Far from a fringe complaint, that asymmetry is the defining feature of the evidence base. When the one dedicated study that finally tested whether cold water immersion aids women’s recovery found no benefit at all, the question it raised was not whether to panic but what to do with an uncomfortable truth.
The study that finally asked the question
In 2025, a team led by Wellauer published what remains the only randomised controlled trial designed to test whether CWI accelerates recovery from exercise-induced muscle damage in women. The study compared cold water immersion, hot water immersion, and passive rest over 72 hours, measuring strength recovery, muscle soreness, and creatine kinase levels.
Neither cold nor hot water immersion produced any measurable recovery benefit compared to doing nothing. The result was unambiguous.
That finding deserves honest attention — not because it proves ice baths don’t work for women, but because it is the only direct evidence we have. One study, one protocol, one population of young, recreationally active women. A small sample, a specific immersion temperature and duration — legitimate reasons not to over-interpret the result. But the inverse is equally true: no women-specific RCT has shown that CWI aids recovery. The positive claims circulating online and in product marketing are extrapolated from studies on men.
Dr Stacy Sims, an exercise physiologist and author of ROAR and Next Level whose work on female physiology has reshaped how many practitioners approach women’s training, puts it plainly: “Women are not small men — and just like everything else — our physiology deserves its own protocol.”
Wellauer’s finding is not the end of the conversation. It is, more accurately, the first sentence.
The scale of what’s missing
None of this is incidental. Piñero and colleagues’ 2024 meta-analysis, the most cited review examining CWI’s effects on hypertrophy, drew on eight studies; seven had exclusively male participants. A BMC 2026 network meta-analysis confirmed the pattern across a broader range of CWI protocol research. When the field’s leading reviews are built on data that is 85 per cent male, every downstream recommendation — temperatures around 10–12°C, durations of 10–15 minutes, applied post-exercise — carries an asterisk that almost nobody prints.
Why women’s cold response may not mirror men’s
Three variables provide plausible mechanisms for a different response. None of them guarantee it. Together, they make the untested assumption harder to defend.
Body composition and cooling depth. Women carry, on average, a higher percentage of subcutaneous fat than men. Subcutaneous fat is an insulator; during cold water immersion, it slows the rate at which cold penetrates to deeper muscle tissue, where the proposed recovery mechanisms (reduced inflammation, blunted secondary damage) are thought to operate. If the cold stimulus is attenuated at the tissue level, the same water temperature may not produce the same effect.
But the insulation story is not simple. Hutchins and colleagues found in 2022 that hyperthermic women actually cool faster than hyperthermic men during cold water immersion. Their paper stated directly that guidelines derived from male cooling data are being applied to women without validation.
And there is a further complication. White and Cabanac’s 2000 study found no significant gender difference in thermosensitivity when body fat percentage and surface area to mass ratio were statistically controlled. Some of what looks like a sex difference may be a body composition difference, which means blanket “protocols for women” could be the wrong frame; individual body composition might matter more than sex itself.
Hormonal cycling. The menstrual cycle introduces a variable that male-only research never encounters. Fuller-Jackson’s 2022 review laid out the mechanistic framework: oestrogen promotes heat dissipation and tends to lower core body temperature, while progesterone raises it. Across a typical cycle, a woman’s thermoregulatory baseline shifts. If CWI’s effectiveness depends partly on the thermal gradient between the body and the water, then the same protocol applied on day 8 and day 22 may produce a meaningfully different stimulus.
Cycle-syncing advice now circulating online rests on this physiological basis. The hormonal mechanism is documented. Its downstream effect on CWI recovery has not been tested.
Where the experts diverge
Three voices dominate the public conversation on women and cold exposure, and they do not fully agree. Their disagreements reveal the shape of the problem.
Sims has taken the most specific public position. She recommends that women use moderate water temperatures — 14 to 16°C for general health benefits, reserving colder protocols of 10 to 12°C for post-competition recovery only. Her reasoning draws on the thermoregulatory and body composition differences above: if women’s tissue cooling operates differently, the standard male-derived temperature may be unnecessarily aggressive or, paradoxically, less effective. Sims’ recommendation is the most specific practical guidance available. Its limitation is honest: it rests on physiological reasoning extrapolated from adjacent research, not on direct CWI trial data in women.
Professor Shona Halson, a recovery researcher at Australian Catholic University who has advised FIFA’s Female Health Project and worked with the US Women’s World Cup team, occupies a different position: practice cannot wait for perfect evidence. Elite women’s teams — FIFA-affiliated physiologists, Premier League women’s squads, Olympic programmes — routinely include CWI in their recovery protocols, sometimes with warmer temperatures, sometimes with shorter durations, frequently with attention to cycle phase. Adapted and already in active use, these protocols reflect a shared conviction: those closest to elite female athletes believe CWI has value, even as they acknowledge the evidence is borrowed. When a 2025 meta-analysis on CWI and wellbeing found sleep improvements in men only, with data on women too limited to draw any conclusion, it was a pointed reminder of what happens when a field doesn’t collect the data it needs.
Dr Susanna Søeberg, a metabolism researcher and founder of the Søeberg Institute, brings a different emphasis. Her argument is that the Wellauer null finding does not indict cold therapy for women; it indicts the assumption that one protocol fits all. Personalisation, she argues, is the necessary next step: individual calibration based on body composition, cold tolerance, training load, and hormonal phase. Her point is not about the tool. It is the protocol.
What women can do right now
Honesty about the evidence gap does not mean paralysis. It means adjusting the confidence level attached to the advice.
Consider warmer water. Sims’ recommendation of 14 to 16°C for general cold exposure is the most specific, physiologically grounded guidance available. If you have been using water at 10°C because that is what a protocol chart prescribes, experiment with slightly warmer temperatures and observe whether your subjective response — alertness, mood, recovery feel — changes. Aim for a stimulus your body registers as cold, not a temperature borrowed from a study that never included you.
Pay attention to your cycle, but do not over-engineer it. Your thermoregulatory set point shifts across your cycle, and the same water temperature may feel and function differently depending on the phase. Track how cold exposure feels at different points. Notice whether your tolerance, your post-immersion response, or your recovery quality varies. That self-collected data is, right now, more relevant to your experience than any published protocol. A cycle-synced framework can help guide your experiments, but resist the temptation to build a rigid phase-by-phase schedule. The evidence for specific cycle-synced CWI protocols does not exist. Awareness is useful. False precision is not.
Monitor your own response over time. In the absence of sex-specific dosing research, your observations carry unusual weight. How do you feel in the hours after cold immersion? Is your sleep affected? Does perceived recovery differ from sessions without CWI? Track this over weeks, not individual sessions. Patterns over weeks matter more than any single session.
Think about your environment. If you use a facility where the cold plunge is set to a single temperature, often calibrated to male-derived protocols, you may not be getting the stimulus that serves you best. Temperature-adjustable setups matter more for women than the current conversation acknowledges. Facilities designed for equal access regardless of gender, and private recovery environments like those at NXT Fit or Rekoop Flex, reflect a reality the research hasn’t caught up with: women are already using cold therapy at the same rates as men. The design should reflect that, including giving users control over their water temperature.
Do not let one null finding override your experience. A 2024 survey of 1,114 women cold-water swimmers reported reductions in anxiety, mood swings, irritability, and sleep difficulties. Survey data without a control group, it sits in a different evidentiary category from an RCT. But it reflects the lived experience of a large number of women who find genuine value in cold water practice. Subjective benefit is not nothing. Cold water and hot flushes, for instance, show promising anecdotal patterns that deserve formal investigation. These experiences deserve to be weighted honestly alongside the clinical picture.
What the field still owes
None of this is women’s problem to solve. It is a structural failing of exercise science, and its consequences extend beyond ice baths into almost every recovery modality, dosing guideline, and performance recommendation in the field. Women have been making decisions based on data that was never generated with their physiology in mind. That some of those decisions may turn out to be correct does not excuse the fact that they were never properly tested.
What changes this is research: sex-balanced cohorts, cycle-phase-controlled study designs, funding bodies willing to invest in the more complicated trials that female physiology demands. The emerging evidence on cold therapy for women’s depression shows what’s possible when research specifically targets women’s needs.
Until that research arrives, women who use cold water immersion are doing what Halson’s elite athletes do: making the best available decision with incomplete information, while paying closer attention to their own response than the standard advice ever asked them to. The issue was never the tool. It was the assumption that a protocol designed without you was designed for you. That assumption is no longer something you have to accept.
