Atlas›Domain X · Body, movement, breath & physical›Guide 196
Guide X-196

Cold-water immersion, ice baths and winter swimming

A 25 · L 64 · M 1115 interventions in the Trinity explorer
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[source: …] where a claim comes from[uncertain] not confirmed in a primary source[synthesis] the writer's reconstruction

1. Introduction

Version followed: UK lifesaving and research guidance — the BJSM editorial "Cold water therapies: minimising risks" (Tipton, Massey, Mayhew and Morgan, 2022), the "Float to Live" advice as the University of Portsmouth, whose research it rests on, presents it and as the RNLI publishes it in its own campaign and cold-water dipping advice (RNLI 2025, 2026), and Outdoor Swimming Society (OSS) safety guidance; for structured group delivery, the OUTSIDE feasibility trial course (Massey et al., 2025).

Cold-water immersion (CWI) covers deliberate entry into cold water: open-water and winter swimming or dipping (sea, lake, river, lido), home or commercial ice baths and cold plunges, and cold showers. It is a practice and a set of settings, not a psychotherapy. Swim clubs, outdoor swim coaches, lifeguards, sports clinicians and commercial providers deliver it; a psychotherapist does not lead it in session. The psychotherapist's work is deciding with the client whether it fits, getting medical screening done, preparing the client, linking it to treatment goals (activity, mastery, social connection, time in nature) and recognising harm. [source: Tipton et al. 2022; Massey et al. 2025]

Proposed ways it may help, as researchers describe them: a strong, brief stress response that people learn to ride through and that becomes smaller with repeated exposure (habituation), plus the mood lift many swimmers report after a swim, social belonging in groups and contact with nature. The editorial calls the mental and physical health benefits "anecdotally claimed". [source: Tipton et al. 2022; Massey et al. 2025] Open-water swimming as a nature practice: see Domain XV.

Evidence status for mood claims (brief). A 2018 BMJ Case Reports paper (van Tulleken, Tipton, Massey and Harper) describes one woman with long-standing depression and anxiety whose mood improved after weekly open-water swims and whose medication was reduced and stopped; a single case report cannot show cause. A 2025 systematic review and meta-analysis of randomised trials in healthy adults (Cain et al., PLoS ONE; 11 studies) found reduced stress at one later time point, improvements in reported sleep and quality of life, no improvement in mood, and an acute rise in inflammation; the authors call the evidence limited. The OUTSIDE feasibility RCT in adults with mild-to-moderate depression (Massey et al., 2025, n = 87) found the eight-session course feasible and acceptable, with exploratory signals favouring it, but the authors state no conclusions can be drawn about effect and it is "too early to recommend" it as a depression treatment. A follow-on trial (OUTSIDE 2) is listed by the NIHR BioResource [uncertain: not verified]. [source: van Tulleken et al. 2018; Cain et al. 2025; Massey et al. 2025] CWI is not a treatment for any physical disease, and it does not replace established treatment for depression.

Who delivers it and how it is regulated. In the OUTSIDE trial, trained outdoor swim coaches and lifeguards ran every session; coaches held basic life support, lifeguarding and mental health first aid qualifications, and a study medical team reviewed health questionnaires. [source: Massey et al. 2025] Clubs and lifeguarded venues vary. For commercial "led" cold-immersion sessions in England, a coroner reported in 2023 that there was little oversight, no specific Health and Safety Executive guidance and no member body or voluntary self-regulation for providers. [source: Prevention of Future Deaths report, Kellie Poole, 2023] Check what a given provider offers rather than assuming a standard. [synthesis]

2. Framework

The sources describe a sequence of stages rather than a therapy course. Durations, water temperatures and exposure schedules are deliberately not given here; the coach, club or venue sets them for the conditions on the day.

  1. Screening and medical clearance. Goal: find people for whom cold shock or cold stress is dangerous. Clinicians use a pre-participation tool such as PAR-Q+/ePARmed-X+ plus cold-specific items (cardiac, respiratory, neurological, cold urticaria, endocrine, medicines, alcohol and drugs), with a 12-lead ECG where indicated. Move on only with clearance or an agreed risk plan. [source: Tipton et al. 2022]
  2. Choosing the setting and support. Goal: never alone. Lifeguarded venues, clubs or experienced companions; a nominated safety observer and agreed emergency signal; visible cap and tow float. Move on when the client has a named supervised option. [source: Tipton et al. 2022; University of Portsmouth "Float to Live"]
  3. Learning the safety skills. Goal: know cold shock and what to do. Float to Live (lie back, float, wait for breathing to settle, then call for help or swim to safety), controlled entry, no jumping or diving in unless acclimatised, planning the exit. [source: University of Portsmouth "Float to Live"; OSS "Will I Get Too Cold?"]
  4. Gradual acclimatisation. Goal: let the body's responses become smaller over repeated exposures. The editorial suggests starting in mid-summer, initially wearing a wetsuit, entering gradually, letting cold shock pass before swimming or putting the face in, keeping early immersions short and within depth, and never judging time in the water by how cold one feels. OSS says to build time in the water gradually and not rush. Move on only as the coach judges. [source: Tipton et al. 2022; OSS]
  5. Exit and rewarming. Goal: manage continued cooling (afterdrop). Dry and dress quickly in warm, windproof layers, get somewhere warm, move about, avoid driving while still cold. [source: Tipton et al. 2022; OSS "The Subtle Art of Warming Up"]
  6. Ongoing practice. Goal: a sustainable, social habit. In OUTSIDE, coaches helped participants form self-organised swimming groups after the course. [source: Massey et al. 2025]

Structured group format (research version). OUTSIDE: eight one-hour coached sessions in small groups (up to eight) at a coastal site, a lake and a lido; weekly at two sites and twice weekly at one, with participants preferring weekly; usual care continued; a site risk assessment before every session and cancellation when conditions were unsafe; gradual entry, teaching on cold shock, floating and self-rescue, shared warm-ups and group activity, rewarming with coach check-ins, and the right to leave the water at any time. [source: Massey et al. 2025]

Psychotherapy alongside. The psychotherapist typically raises the idea, gets screening done, prepares the client over one or two sessions, then reviews experiences within ongoing therapy. [synthesis]

3. Guiding principles

  • Cold shock is the main immediate danger, not hypothermia. Plan around the first moments in the water: controlled entry, no breath-holding, wait for breathing to settle. [source: Tipton et al. 2022; University of Portsmouth "Float to Live"]
  • Never alone. Recommend only supervised or accompanied practice, including home ice baths. [source: Tipton et al. 2022]
  • Screen first. No first significant cold challenge without medical assessment; send medicine questions to the prescriber. [source: Tipton et al. 2022]
  • Gradual, not heroic. Acclimatise over time; the sources reject rushing. [source: OSS; Tipton et al. 2022]
  • Feeling is not a safe gauge. With repeated exposure the sense of cold becomes unreliable, so time and conditions are set by plan, not by how it feels. [source: Tipton et al. 2022]
  • No breathwork in or before water. Hyperventilation and breath-holding do not mix with immersion. [source: Live Science 2024, reporting expert and Wim Hof organisation statements; Tipton et al. 2022]
  • No alcohol or drugs. They are associated with fatalities. [source: Tipton et al. 2022]
  • The right to stop. The client can leave the water at any moment, and skipping a session is not failure. [source: Massey et al. 2025; synthesis]
  • Honest expectations. Present mood benefits as unproven; CWI is an add-on, not a replacement for treatment. [source: Cain et al. 2025; Massey et al. 2025]
  • Values, not dares. Tie the practice to the client's goals (connection, activity, nature), not to endurance or online challenges. [synthesis]
  • Respect the professionals' roles. Coaches, lifeguards and medical staff own the in-water and medical decisions; the psychotherapist owns preparation, meaning and monitoring. [synthesis]

4. Intervention inventory

These are the psychotherapist's tasks around a practice that others deliver, plus the published safety components the client will meet, so you can prepare them accurately. No temperatures, durations or exposure schedules are given as instructions anywhere in this inventory.

4.1 Exploring interest and motives

  • Purpose / when: When a client raises cold dipping, ice baths or winter swimming, or when you consider it as a behavioural-activation or social-connection option. [synthesis]
  • Steps: (1) Ask what draws them (friends, nature, a challenge, something seen online, hope it will fix low mood). (2) Ask what they already do (cold showers, solo home plunges, breathing routines). (3) Note risk-raising motives: proving toughness, punishment, numbing, replacing medication, a dare or online challenge. (4) Link to therapy goals only where it fits their values. [synthesis]
  • Example language (illustrative): "What would you be hoping to get from it, and what would it mean to you if it turned out not to be your thing?"
  • Watch for: Escalation talk (colder, longer, alone), self-punishing framing, plans to stop medication, active suicidal ideation (cold open water is then not appropriate; follow standard risk assessment). Working: the client can name a values-based reason and is open to a supervised start. [synthesis]

4.2 Referral for medical screening

  • Purpose / when: Before any first significant cold challenge. [source: Tipton et al. 2022]
  • Steps: (1) Explain that screening is standard, not a judgement. (2) Ask the client to see their GP or a sport and exercise clinician. (3) Share the categories the editorial lists so the client can mention them: family history of sudden or unexplained cardiac death; high blood pressure, rhythm problems, structural or ischaemic heart disease; Raynaud's and other peripheral vascular disorders; cold-induced, exercise-induced or unstable asthma, other lung disease or recent chest infection; epilepsy and other seizure disorders; peripheral nerve disorders; cold urticaria; unstable diabetes and other endocrine conditions; sight and hearing problems; medicines that prolong the QT interval or alter cold responses. The editorial notes the list is not exhaustive and suggests PAR-Q+/ePARmed-X+ plus a 12-lead ECG where indicated. (4) Agree that the client starts only after clearance. [source: Tipton et al. 2022] Pregnancy is not in the list as summarised here; ask the client to raise it with their midwife or doctor [synthesis; uncertain: not verified in the editorial].
  • Example language (illustrative): "Cold water puts a sudden load on the heart and breathing, so the people who run these sessions recommend a health check first. Could you book that before we plan anything?"
  • Watch for: Minimising ("I'm fit, I don't need it"), undisclosed palpitations or fainting, family sudden deaths. Working: the client returns with clearance or a clear no.

4.3 Medicines, alcohol and drugs check

  • Purpose / when: At planning, and whenever medication changes. Medicines that alter cold perception or prolong the QT interval, and alcohol and recreational drugs, raise risk. [source: Tipton et al. 2022]
  • Steps: (1) Ask what the client takes, including antihistamines and psychiatric medicines. (2) Do not advise on any medicine; route the question to the prescriber or pharmacist. (3) State plainly: no alcohol or drugs before cold water. (4) If the client hopes to come off antidepressants by swimming, say that any change belongs with the prescriber. [source: Tipton et al. 2022; synthesis]
  • Example language (illustrative): "Some medicines change how the heart or body reacts to cold. That's a question for your prescriber, so let's write it down for them."
  • Watch for: Drinking after or before dips as part of the social ritual; plans to self-taper. Working: the prescriber has been asked and the client has an alcohol-free plan.

4.4 Choosing a safe setting and support

  • Purpose / when: After clearance. [source: Tipton et al. 2022; University of Portsmouth "Float to Live"]
  • Steps: (1) Help the client find a lifeguarded venue, a club or a coached course (e.g. a lido or a group with trained coaches). (2) Check what the provider does: health questions, site risk assessment, briefing on entry and exit points, a rewarming area, first aid with CPR and AED, an emergency plan, and willingness to cancel in poor conditions. (3) For any outdoor swim: an experienced companion and a named safety observer on land, an agreed emergency signal, a bright cap and a tow float marked with name and emergency number, and a whistle. (4) For home ice baths and plunges, apply the same never-alone principle. [source: Tipton et al. 2022; synthesis for 4]
  • Example language (illustrative): "Which of these places has a lifeguard or coach on the day? I'd feel much better if your first times are with people trained for this."
  • Watch for: Plans to start alone at dawn or after dark, in rivers or reservoirs, or with an unregulated provider; the coroner noted open waters such as rivers, lakes and reservoirs can add risk. Working: a named supervised option and a companion. [source: PFD report 2023]

4.5 Psychoeducation: cold shock and Float to Live

  • Purpose / when: Before the first immersion, especially for anxious clients. [source: University of Portsmouth "Float to Live"]
  • Steps: (1) Explain cold shock: a sudden drop in skin temperature triggers an involuntary gasp, fast breathing, a stress-hormone surge, a rise in blood pressure and possible heart-rhythm disturbance; it is strongest in the first moments and then passes. (2) Explain that a gasp under water can start drowning, which is why controlled entry matters and jumping or diving in is discouraged. (3) Teach the RNLI message: if in trouble, resist thrashing or swimming hard; lean back with ears in the water, spread arms and legs, try to breathe normally and use small hand and foot movements to stay afloat (legs sinking is normal, since people float differently); once breathing is under control, call for help or swim to safety. The RNLI suggests practising floating in a local pool. (4) If someone else is in danger, call 999 or 112 and ask for the Coastguard rather than going in; tell them to float on their back and throw them something that floats. [source: RNLI Float to Live campaign 2026; RNLI cold-water dippers advice 2025; University of Portsmouth "Float to Live"; Tipton et al. 2022; OSS]
  • Example language (illustrative): "The gasp and racing breath are a reflex, not a sign you're failing. The skill is to stay calm, lie back and float until it passes." Tipton's phrase: "you've simply got to have the confidence to do nothing" [source: University of Portsmouth].
  • Watch for: Catastrophic interpretation of the reflex ("I'm having a heart attack"), which can feed panic in the water. Working: the client can describe the sequence and the float response in their own words.

4.6 Preparing clients with anxiety, panic or trauma histories

  • Purpose / when: For clients prone to panic, health anxiety, or with water-related or medical trauma. In OUTSIDE, non-serious adverse events included panic when out of depth and anxiety at not seeing the bottom. [source: Massey et al. 2025]
  • Steps: (1) Map expected sensations (gasp, breathlessness, tingling, numb hands) and the client's usual panic signals. (2) Agree a personal plan: stay within depth, near the exit, with the coach informed of any anxiety (with consent). (3) Rehearse in session a calm-attention script for the gasp phase, without breath-holding or breathing manipulations. (4) Agree that getting out early is a good decision, not avoidance. (5) Review afterwards. [synthesis, informed by Massey et al. 2025 and RNLI]
  • Example language (illustrative): "Let's work out what you'll notice in the first moments, what your mind might say about it, and what you'll do, including getting straight out if you need to."
  • Watch for: Dissociation, freezing, re-experiencing of past near-drowning. Panic disorder with water fear may need graded exposure work on land or in a pool first. Working: the client enters with a plan and reports manageable arousal. [synthesis]

4.7 Graded acclimatisation as behavioural activation

  • Purpose / when: When the client wants a regular practice; links to activity scheduling and mastery. [source: Tipton et al. 2022; OSS; synthesis for BA framing]
  • Steps: (1) Agree the coach's or club's progression as the frame; the therapist does not set exposure times. (2) Schedule the session like any valued activity (day, people, transport, kit). (3) Use the published principles: start in the warmer months, consider a wetsuit, gloves and booties, enter gradually, let breathing settle before swimming or putting the face in, keep early dips short and within depth, stay near the shore, and do not judge time by how cold it feels. (4) Track mood, enjoyment and mastery before and after, alongside usual measures. [source: Tipton et al. 2022; OSS; synthesis for 2 and 4]
  • Example language (illustrative): "Let's treat this like any other activity we plan: when, who with, and how you'll notice what it does for your mood."
  • Watch for: Pushing beyond the coach's guidance, comparing with others online, numb or weak hands (OSS: if the client cannot touch thumb to second fingertip, they are incapacitated and should get out). Working: regular attendance, enjoyment and mastery ratings, no adverse events. [source: OSS]

4.8 Exit, rewarming and afterdrop plan

  • Purpose / when: Every client, before the first dip. [source: OSS; Tipton et al. 2022]
  • Steps: (1) Explain afterdrop: cooled blood from limbs and skin keeps chilling the core after leaving the water, so one can feel colder afterwards, with shivering, faintness or nausea. (2) Plan the exit point in advance, since cold weakness makes climbing out harder. (3) Agree a routine: dry off and dress quickly in warm, windproof layers with hat and gloves, stand on something insulating, a warm drink, get somewhere warm, move about; avoid very hot showers or baths because heat may not be sensed accurately. (4) No driving while still cold or shivering. (5) Lay out kit in order before getting in. [source: OSS "The Subtle Art of Warming Up"; Tipton et al. 2022; synthesis for 5]
  • Example language (illustrative): "The part after you get out matters as much as the swim. What's your plan for getting warm, and who will be with you?"
  • Watch for: Lingering wet on the shore, fainting, confusion, uncontrollable shivering (seek help). Working: the client describes the routine and uses it.

4.9 Social connection and group belonging

  • Purpose / when: For isolated or low-mood clients; OUTSIDE participants described themes of belonging and facing challenges with support. [source: Massey et al. 2025]
  • Steps: (1) Identify a group with a welcoming culture and clear safety practice. (2) Plan the social side (arriving, introductions, staying for a drink afterwards). (3) After a coached course, support joining or forming a regular group, as OUTSIDE coaches did. (4) Review interpersonal experiences in therapy. [source: Massey et al. 2025; synthesis for 2 and 4]
  • Example language (illustrative): "It sounds like the people you swim with matter as much as the water. How could you keep that going after the course ends?"
  • Watch for: Social anxiety, body-image distress in changing areas, group norms that reward risk. Working: regular contact and reported belonging.

4.10 Body image, changing and modesty

  • Purpose / when: Swimwear and outdoor changing can be hard for clients with body-image concerns, eating disorders, religious modesty requirements, gender dysphoria or trauma. [synthesis]
  • Steps: (1) Ask about changing arrangements and clothing norms at the venue. (2) Problem-solve options (changing robes, wetsuits, private changing, women-only or other groups where available). (3) Process feelings that arise. [synthesis]
  • Example language (illustrative): "Some people find the changing part harder than the cold water. What would make that bit feel manageable for you?"
  • Watch for: Use of cold to compensate for eating or to burn calories (screen for eating disorders), shame, avoidance. Working: the client can attend without distress dominating. [synthesis]

4.11 Ice baths, home plunges and cold-plus-breathing routines

  • Purpose / when: When a client uses or plans home ice baths, commercial plunge sessions or routines that pair cold with breathing exercises (e.g. methods popularised by Wim Hof). [source: Live Science 2024; Tipton et al. 2022]
  • Steps: (1) Ask exactly what the routine involves, where, and who is present. (2) Explain the two specific dangers: breath-holding with the face in cold water can provoke dangerous heart rhythms ("autonomic conflict" between cold shock and the diving response), and hyperventilation or breath-holding can cause blackout without warning, which in water can lead to drowning. (3) Share that the Wim Hof organisation's own written safety materials, as reported, say to sit or lie down for the breathing and never to practise it before or during water immersion. (4) Advise: never alone, no breathwork in or before water, face out of the water, no alcohol. (5) For breathwork itself, see Domain X breathwork entries and, for intense breathwork, Domain VII. [source: Tipton et al. 2022; Live Science 2024]
  • Example language (illustrative): "The breathing part and the cold part are each things to do carefully, and the sources are clear they shouldn't be combined in water. Could we keep them separate, with someone else present?"
  • Watch for: Following social-media videos rather than written safety guidance; solo bathtub plunges; competitive timing. Working: the client separates breathing practice from immersion and is never alone. Risk flag: see Harm account.

4.12 Integrating the experience in session

  • Purpose / when: After each early immersion and periodically thereafter. [synthesis]
  • Steps: (1) Ask for a sensory account (before, entry, in water, exit, afterwards). (2) Ask what the mind said during the gasp phase and how they responded. (3) Explore meaning: mastery, aliveness, connection, nature. (4) Link to therapy targets (tolerating discomfort, approaching rather than avoiding, self-care). (5) Note mood before and after and over weeks. [synthesis]
  • Example language (illustrative): "Walk me through it from the moment your feet went in. What did you notice in your body, and what did you tell yourself?"
  • Watch for: Mood lift that depends on increasingly intense exposures (escalation), use of cold to numb distress or as self-punishment, or swimming replacing other coping and treatment. Working: the client describes a flexible, enjoyable practice that supports, not replaces, other goals. [synthesis]

4.13 Managing expectations about mood benefits

  • Purpose / when: Whenever a client expects cold water to treat depression or anxiety. [source: Cain et al. 2025; Massey et al. 2025; van Tulleken et al. 2018]
  • Steps: (1) Say what is known: one well-known case report, a review of trials in healthy adults showing no mood improvement but some stress, sleep and quality-of-life findings, and a feasibility trial with promising but inconclusive results. (2) Frame CWI as a possible add-on. (3) Continue evidence-based treatment and any medication as prescribed. [source: as listed; synthesis for 2 and 3]
  • Example language (illustrative): "Some people feel great after a swim, and researchers are testing whether it helps depression. It isn't proven yet, so let's see it as something extra alongside what we're already doing."
  • Watch for: Disappointment if no lift; plans to stop treatment. Working: realistic expectations and continued engagement.

4.14 Recognising and passing on adverse effects

  • Purpose / when: Throughout. [source: Tipton et al. 2022; Massey et al. 2025; synthesis]
  • Steps: (1) Ask after each dip about chest pain, palpitations, fainting, breathlessness, confusion, prolonged shivering, painful or numb fingers, panic. (2) Send physical symptoms to the GP or emergency care; chest pain or collapse is an emergency. (3) Tell the coach or provider, with consent, about incidents. (4) Pause practice until reviewed. [synthesis, informed by Tipton et al. 2022; painful tingling fingers resolved with neoprene gloves in OUTSIDE]
  • Example language (illustrative): "Palpitations in cold water are something your doctor needs to know about before you go in again. Can you call them this week?"
  • Watch for: Concealment to keep swimming. Working: symptoms are reported and reviewed.

4.15 Open-water swimming as a nature practice

  • Pointer: for open-water swimming as time in nature, blue-space and nature-connection practice, see Domain XV. The safety components in 4.2 to 4.8 apply there too.

5. Handling problems

  • Client wants to skip screening. Explain that screening is standard practice recommended by the lifesaving and research bodies, not a doubt about their fitness; offer help booking. If they refuse, say you cannot support the plan and document the discussion. [source: Tipton et al. 2022; synthesis]
  • Client already swims alone or plunges alone. Avoid lecturing; explore what solitude gives them, then problem-solve a companion, a club or a land-based observer. [synthesis; never-alone principle from Tipton et al. 2022]
  • Escalation and "challenge" culture. If the client seeks colder, longer or more extreme exposures, or online challenges, explore function (proof, numbing, self-worth) and reconnect to values; involve the coach. [synthesis]
  • Panic in the water. Review with the client, return to land- or pool-based preparation, stay within depth, and revisit Float to Live; consider graded exposure work for water fear in therapy first. [source: Massey et al. 2025 for adverse events; University of Portsmouth "Float to Live"; synthesis]
  • Non-adherence. Cold discomfort put some OUTSIDE participants off. Normalise this, adjust (wetsuit, gloves, a lido rather than open water, weekly rather than more frequent), or drop it without failure: other activities serve the same goals. [source: Massey et al. 2025; synthesis]
  • No mood benefit. Revisit expectations (4.13); the evidence does not promise one. [source: Cain et al. 2025]
  • Plans to stop medication. Route to the prescriber; do not endorse self-tapering, even citing the 2018 case report. [synthesis]
  • Alcohol in the social ritual. Be explicit that alcohol is linked to cold-water deaths; plan alternatives. [source: Tipton et al. 2022]
  • Suicidal clients. Cold open water near a person with active suicidal intent is a means-access concern; follow standard risk assessment and safety planning and postpone the practice. [synthesis]
  • Eating disorders and self-harm. Cold used to burn calories, to punish or to numb calls for formulation and, where relevant, eating-disorder assessment. [synthesis]
  • Unregulated providers. Help the client check safety practice (see 4.4), remembering the coroner's finding that the led-session sector had little oversight in 2023. [source: PFD report 2023]
  • Rupture. If the client experiences your caution as disapproval, acknowledge their autonomy, restate that your goal is their safety and enjoyment, and invite them to bring the coach's view. [synthesis]
  • Physical adverse event. Stop, route to medical care, inform the provider with consent, and review emotionally (fear, shame, loss of a valued activity). [synthesis]

Harm account

What was actually done

  • Unprepared entry into cold open water. The pattern behind the RNLI campaign: people enter cold sea, lake or river water suddenly (jumping, diving, wading into rough water), often unacclimatised, alone or without a plan, then gasp, hyperventilate and try to swim hard. The editorial reports that HM Coastguard call-outs related to swimming and dipping rose 52% in 2021 and that UK open-water swimming deaths rose from 34 in 2018 to 61 in 2021. [source: University of Portsmouth "Float to Live"; Tipton et al. 2022]
  • Led commercial cold-immersion sessions in open water. On 25 April 2022, Kellie Poole, aged 39, collapsed in the River Goyt near Whaley Bridge, Derbyshire, during a led cold-water immersion session run by a commercial provider (named in the report). The coroner found the cold water likely triggered a heart-rhythm disturbance causing sudden cardiac death, with a previously undiagnosed heart abnormality likely preventing recovery. The Prevention of Future Deaths report (4 October 2023) was sent to the Health and Safety Executive. [source: PFD report 2023]
  • Breathing techniques combined with water. People practised hyperventilation-style breathing and breath-holds in or before water, sometimes copying online videos. Live Science (2024) reports that Het Parool in 2016 described at least three deaths among people combining such breathing with water immersion, and that journalist Scott Carney links 31 deaths, mostly drownings, to the Wim Hof Method from news reports and private accounts; none had been confirmed in court as involving the method [uncertain: counts unverified]. Deaths of young people are among those reported; they are not named here. [source: Live Science 2024]
  • Ice-water challenges on social media. In 2014, during the ice-bucket and "ice challenge" trends, Yahoo News Australia reported that a 40-year-old man in New Zealand died of a heart attack after having ice water poured over him and then drinking a large amount of spirits; the report gives no official cause beyond the heart attack [uncertain: cause and link to cold not established]. Other news reports from 2014 linked teenagers' deaths to variants of such challenges [uncertain]; they are not named here. [source: Yahoo News Australia 2014]
  • Over-staying and "pushing through". Swimmers whose sense of cold had blunted with habituation stayed in longer or swam further from the exit, with sudden muscle weakness. The editorial cites a historical case (Jason Zirganos) in discussing undetected hypothermia. [source: Tipton et al. 2022; OSS]

How it caused harm

  • Cold shock. A rapid fall in skin temperature triggers gasping, hyperventilation, stress hormones, high blood pressure and arrhythmias; it is described as the most dangerous immediate response. A gasp under water can draw in water and start drowning; loss of breathing control also makes swimming impossible. [source: Tipton et al. 2022; University of Portsmouth "Float to Live"]
  • Arrhythmia and autonomic conflict. Face immersion with breath-holding activates the diving response (slowing the heart) at the same time as cold shock (speeding it), which can cause dangerous rhythms; long-QT syndrome and QT-prolonging medicines are particular concerns for sudden death. Undiagnosed structural heart disease was implicated in the 2022 death. [source: Tipton et al. 2022; Live Science 2024; PFD report 2023]
  • Swim failure and incapacitation. Muscle and nerve cooling weakens arms and legs, even in strong swimmers, sometimes with little warning; exits that looked easy become impossible. [source: Tipton et al. 2022; OSS]
  • Hypothermia and afterdrop. Core temperature can keep falling after leaving the water as cooled tissue continues to chill the core; shivering, faintness and nausea follow, and impaired function makes driving dangerous. [source: OSS "The Subtle Art of Warming Up"; Tipton et al. 2022]
  • Blackout from breathing manipulation. Hyperventilation and breath-holding lower carbon dioxide, delaying the urge to breathe and reducing brain blood flow, so unconsciousness can occur without warning; in water, with no one close, this leads to drowning. [source: Live Science 2024, citing a 2015 CDC report]
  • Alcohol and drugs, illness and exhaustion. Associated with fatalities and with poorer cold tolerance. The editorial cites a study suggesting up to 43% of drownings are associated with pre-existing medical conditions. [source: Tipton et al. 2022]
  • Psychological harm. Panic and anxiety in the water (reported as adverse events in OUTSIDE), fear after near-drowning, and bereavement for families and fellow swimmers after a death. [source: Massey et al. 2025; synthesis for the last two]
  • Most at risk: people with known or undiagnosed heart disease or a family history of sudden cardiac death, rhythm disorders, QT-prolonging medicines, asthma or lung disease, epilepsy, cold urticaria, Raynaud's, unstable diabetes; anyone who has been drinking; anyone alone, unacclimatised, entering suddenly, or combining breath-holding or breathwork with water. [source: Tipton et al. 2022]

Recognising it today

  • Phrases and rationales: "the colder the better", "push through", "beat your time", "no wetsuits", "it'll cure your depression" or "get off your meds", "just breathe and go under". [synthesis, drawing on Tipton et al. 2022 and Live Science 2024]
  • Practices: solo home ice baths or bathtub plunges; jumping or diving into cold water; breath-holds or hyperventilation in or just before water; face-down breath-hold challenges; timed endurance challenges filmed for social media; drinking before or after dips; swimming far from shore without support; driving home while still shivering. [source: Tipton et al. 2022; OSS; Live Science 2024]
  • Red flags in a provider or group: no health questions or medical-clearance advice; no site risk assessment, briefing on entry and exit, rewarming area, first-aid cover or emergency plan; sessions run in rivers, lakes or reservoirs regardless of conditions; breathwork combined with immersion; leaders without lifeguard or first-aid training; pressure to stay in; no right to leave. The coroner noted no specific HSE guidance and no self-regulating body for this sector in 2023. [source: Tipton et al. 2022; PFD report 2023; Massey et al. 2025]
  • How legitimate versions differ: screening and clearance first; lifeguarded or coached settings; gradual entry and acclimatisation; Float to Live taught; time set by plan, not by feel; exit and rewarming planned; breathing practice kept out of the water; the right to stop at any time. [source: Tipton et al. 2022; OSS; University of Portsmouth "Float to Live"; Massey et al. 2025]

What to do instead and how to help those harmed

  • Safer alternatives: a coached beginners' course or club with lifeguards; a lifeguarded lido; wetsuit swimming in warmer months; if the aim is mood, activity or connection, other forms of exercise, group activity or nature-based practice (Domain XV) alongside evidence-based treatment. [source: Tipton et al. 2022; Massey et al. 2025; synthesis]
  • Assessing affected clients: for clients after a near-drowning, collapse or witnessed death, assess for acute stress reactions and PTSD, panic, health anxiety and avoidance; check that physical follow-up (cardiac assessment after collapse or palpitations) has happened. [synthesis]
  • Treatment considerations: trauma-focused treatment where PTSD is present; graded, consent-based return to water only if the client wants it and is medically cleared; grief work for bereaved families and swim companions; address self-blame and blame of others carefully. [synthesis]
  • Ethical, reporting and legal duties: do not recommend unsupervised immersion or providers without basic safety practice; document risk discussions; encourage clients to report incidents to the provider and venue; where a death occurs in England and Wales, the coroner's process applies and Prevention of Future Deaths reports are sent to bodies such as the HSE. Follow your professional body's code and safeguarding procedures where children or adults at risk are involved. [source: PFD report 2023; synthesis for the rest]

Sources

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