Cold Plunge for Anxiety & Depression – Does It Help?

KEY TAKEAWAY: Cold plunges show genuine promise for anxiety and depression, but the evidence isn’t as strong as social media suggests. Cold water immersion triggers a large release of norepinephrine (up to 530% increase) and dopamine (250% increase) neurotransmitters directly involved in mood, focus, and motivation. Cortisol (the stress hormone) spikes briefly during immersion but drops below baseline within 1-3 hours. One case study documented a woman with major depressive disorder discontinuing medication after regular cold water swimming. However, the first large-scale RCT on cold water and depression is still underway, and existing studies are small. Cold plunges may complement professional mental health treatment, they should not replace it.

IMPORTANT NOTE – This guide discusses anxiety and depression in a research context. If you’re currently experiencing a mental health crisis, please contact Lifeline Australia or Beyond Blue Cold water immersion is not a substitute for professional mental health treatment including therapy and medication. If cold plunging interests you as a complement to existing treatment, discuss it with your psychologist or psychiatrist first.

You step into the water and the cold hits like a reset button. For a few seconds, there’s nothing but the cold – no rumination, no spiralling thoughts, no background hum of worry. Just you, the water, and the immediate, overwhelming need to breathe.

That experience – the way cold exposure seems to interrupt anxious thought patterns and replace them with acute, manageable focus – is what draws so many people to cold plunging for mental health. Ask anyone who does it regularly and they’ll describe the same thing: a calm that settles in after the initial shock and lasts for hours.

But does the science back it up? Are cold plunges actually good for anxiety and depression, or is this another wellness trend running ahead of the evidence?

The honest answer is somewhere in between. The neurochemical effects are real and measurable. The mood improvements are consistently reported. But the clinical evidence for treating diagnosed anxiety and depression disorders is still in its early stages. This guide separates what we know from what we hope, and gives you a practical framework for using cold exposure alongside – not instead of – professional treatment. For the full picture on cold plunge benefits beyond mental health, see our comprehensive science guide.

What the Research Shows at a Glance

The Neurochemistry: What Cold Water Does to Your Brain

KEY TAKEAWAY: Cold water immersion triggers the release of norepinephrine, dopamine, and endorphins – neurotransmitters that are directly implicated in depression and anxiety. These are the same chemicals targeted by common psychiatric medications like SNRIs and bupropion.

Norepinephrine: the alertness and mood chemical

Šrámek et al. (2000) measured a 530% increase in plasma norepinephrine after cold water immersion at 14°C (DOI: 10.1007/s004210050065). Critical context: this was a 1-hour immersion, far longer than a typical cold plunge. Shorter immersions still produce significant norepinephrine release, though the exact magnitude scales with duration and temperature. Johnson (1977) found norepinephrine increased after just 2 minutes in 10°C water.

Why this matters for anxiety and depression: norepinephrine is a key target of SNRI medications (like venlafaxine and duloxetine), which are among the most commonly prescribed drugs for both conditions. Low norepinephrine is associated with fatigue, poor concentration, and low motivation core symptoms of depression. Cold exposure produces a natural, sustained elevation that can last 2-3 hours after a single session.

Dopamine: the motivation and reward chemical

Šrámek et al. also measured a 250% increase in dopamine during their 1-hour protocol. As Psychology Today summarised, this sustained dopamine elevation is qualitatively different from the sharp spikes produced by addictive substances it’s a gradual rise that supports stable mood and motivation rather than a crash-and-crave cycle.

Dopamine is central to depression: low dopamine is linked to anhedonia (inability to feel pleasure), reduced motivation, and the ‘flatness’ that many people with depression describe. While no RCT has tested whether cold-plunge-induced dopamine elevation translates to lasting clinical improvement, the neurochemical pathway is biologically plausible.

Endorphins: the body’s painkillers

The evidence on endorphins is more mixed. Reed et al. (2023) found that β-endorphin levels did not change significantly during or after a 15-minute CWI at 10°C. Other studies report increases, but the data is inconsistent. Endorphins may contribute to the post-plunge ‘high’ some people describe, but they’re not the primary driver of cold exposure’s mental health effects.

Does Cold Plunge Increase or Reduce Cortisol?

KEY TAKEAWAY: Both – and that’s the point. Cold plunging causes a brief cortisol spike during immersion (it’s a stressor), but cortisol drops below baseline within 1-3 hours. With regular practice over weeks, your baseline cortisol response to cold diminishes – your body adapts, and the stress hormone stays lower for longer.

The cortisol question is the most commonly misunderstood aspect of cold plunging and mental health. Here’s the timeline:

• During immersion (0-15 min): Cortisol increases. Your body recognises cold water as a stressor and activates the HPA (hypothalamic-pituitary-adrenal) axis. This is normal and expected it’s the same stress response you’d get from intense exercise or a challenging situation.
• 1-3 hours after immersion: Cortisol drops below pre-immersion baseline. Reed et al. (2023) measured a 47% reduction in cortisol at 180 minutes post-CWI (15 min at 10°C) compared to pre-immersion levels. Negative mood also decreased at the same timepoint. A Stanford Lifestyle Medicine review noted that cortisol levels remain considerably lower for up to three hours after just 15 minutes of CWI.
• With regular practice (4-12 weeks): Your cortisol response adapts. Leppalüoto et al. (2008) tracked women doing winter swimming or cryotherapy 3x/week for 12 weeks. By week 4, plasma cortisol at 15 and 35 minutes post-immersion was significantly lower than in week 1. The body learns that cold is not a threat, and the stress response diminishes.

The bottom line: Cold plunging does increase cortisol acutely but this is a feature, not a bug. The temporary stress followed by a sustained reduction is the same hormetic pattern that makes exercise beneficial for anxiety. You deliberately expose yourself to a manageable stressor, your body overcompensates in recovery, and over time your stress tolerance increases. It’s stress inoculation, not stress accumulation.

Can Cold Plunges Help Depression?

KEY TAKEAWAY: The evidence is promising but preliminary. One landmark case study documented full remission from major depressive disorder after cold water swimming. The neurochemical effects (norepinephrine, dopamine elevation) target the same pathways as antidepressant medication. But we don’t yet have large RCTs proving efficacy for clinical depression.

The van Tulleken case study (2018)

The most cited piece of evidence for cold water and depression is a BMJ Case Report by van Tulleken et al. (2018). A 24-year-old woman with major depressive disorder and anxiety, who had not responded adequately to medication (fluoxetine and citalopram) or CBT, began a programme of weekly open cold water swimming at a beach in southern England under the supervision of Professor Mike Tipton and Dr Mark Harper. After four months, she was able to discontinue all medication and remained symptom-free at one year follow-up (van Tulleken et al., 2018).

Important caveats: This is a single case study. It cannot establish causation. The woman also gained social connection (swimming group), physical exercise (swimming), outdoor nature exposure, and a sense of challenge and achievement all of which independently benefit depression. Cold water may have been additive to these factors, not solely responsible.

The Blades et al. RCT (2024)

This is the study that should temper expectations. Blades et al. tested the Wim Hof Method (cold showers + rapid breathing) versus an active control (warm showers + slow breathing) in 78 women with depressive symptoms. Both groups improved by 20-30% on depression and anxiety scales but there was no difference between groups. The cold exposure did not outperform the active control. However, the cold showers may not have been cold enough to trigger robust physiological responses, and the breathing component may have been the more important factor.

The Harper/Massey RCT (ongoing)

The most important study on this topic is currently underway. Professor Mark Harper and Dr Heather Massey at the University of Portsmouth are running the first large randomised controlled trial of cold water swimming as a therapeutic intervention for anxiety and depression. Results are expected in the coming years. Until this trial reports, we’re working with suggestive but not conclusive evidence.

The Cain/UniSA meta-analysis (2025)

The Cain et al. (2025) meta-analysis (11 studies, 3,177 participants) found stress reduction at 12 hours post-CWI and improvements in quality of life. However, the authors noted that the overall evidence for specific mental health outcomes (depression, anxiety) remains inconclusive due to study heterogeneity and small sample sizes.

Can Cold Plunges Help Anxiety?

KEY TAKEAWAY: The mechanism for anxiety relief is strong-cold exposure activates the parasympathetic nervous system (via the vagus nerve), reduces cortisol over hours, and produces a subjective calm that people consistently report. But direct clinical evidence for diagnosed anxiety disorders is limited.

The anxiety story is somewhat different from depression. While depression research focuses on dopamine and norepinephrine deficits, anxiety involves an overactive stress response the HPA axis fires too readily, cortisol stays elevated, and the sympathetic nervous system (fight or flight) dominates.

Cold plunging may help through several pathways:

• Vagal nerve stimulation. Cold water on the face and neck activates the vagus nerve, which triggers the parasympathetic (‘rest and digest’) nervous system. Will Cronenwett, Chief of Psychiatry at Northwestern University, explained that while ice baths temporarily activate the sympathetic system, the cold on the face and neck simultaneously engages the calming parasympathetic response.
• Stress inoculation. Regular exposure to a controlled stressor (cold water) may train your nervous system to recover from stress more efficiently. This is the hormesis model: deliberate, manageable stress builds resilience. Over weeks, the HPA axis adapts and cortisol responses diminish (Leppalüoto et al., 2008).
• Attention interruption. Anxiety is characterised by rumination repetitive, uncontrollable worry. Cold water immersion demands absolute present-moment attention. For 2–5 minutes, your brain has no bandwidth for worry. Many people report that this ‘reset’ breaks the cycle of anxious rumination and the calm persists for hours.
• Cortisol reduction. As outlined in Section 2, cortisol drops below baseline within 1–3 hours of CWI and baseline responses diminish with regular practice. For people whose anxiety is driven by chronically elevated cortisol, this pattern is therapeutically relevant.

Yankouskaya et al. (2023) used fMRI to show that just 5 minutes of whole-body CWI at 20°C increased neural interaction between large-scale brain networks, with participants reporting increased positive emotions and decreased negative feelings. The brain connectivity changes occurred in regions involved in attention control, emotion regulation, and self-awareness (DOI: 10.3390/biology12020211).

A Practical Cold Plunge Protocol for Mental Health

If you’re considering cold plunges as a complement to your mental health management, here’s an evidence-informed protocol:

• Temperature: 10-15°C. Dr Mark Harper’s research suggests maximum mood response occurs between 10-15°C with no further significant benefit below 10°C. Start at 15°C if you’re new. For detailed guidance, see our temperature guide.
• Duration: 2–5 minutes per session. Norepinephrine increases significantly within 2 minutes (Johnson, 1977). You don’t need marathon sessions for mood benefits. See our duration guide.
• Frequency: 2-4 times per week for sustained effects. Leppalüoto showed adaptation from week 4 onward with 3x/week exposure. Consistency matters more than intensity.
• Timing: Morning or midday sessions may be most beneficial for anxiety, as the norepinephrine and dopamine elevation provides sustained alertness and focus through the day. Evening sessions (especially ending on cold) may disrupt sleep if done within 90–120 minutes of bedtime.
• Breathing: Focus on slow, controlled exhales during immersion. Avoid hyperventilation or Wim Hof-style rapid breathing in the water. Controlled breathing activates the parasympathetic nervous system, the calming effect you’re after.
• Social component: Where possible, plunge with others. Much of the mental health benefit in the literature may come from social connection, community, and shared challenge not cold alone. This is one reason cold water swimming groups report such strong wellbeing effects.
• Do not replace professional treatment. Cold plunges can complement therapy and medication. They should not replace them. Discuss with your mental health professional before adding cold exposure to your routine, especially if you have a diagnosed anxiety or depressive disorder.

Cold Plunges, Anxiety, and Women

Most cold water research has been conducted on men. Hormonal cycles, body composition differences, and thermoregulation differences mean women may respond differently to cold exposure. The Blades et al. (2024) study specifically tested women and found mood improvements but couldn’t isolate cold from breathing. If you’re a woman interested in cold plunging for mental health, our complete female guide to ice baths covers the research and practical considerations specific to women’s physiology.

7. What the Science Doesn’t Support

• Cold plunges cure depression. No single study has shown this. One case study (van Tulleken, 2018) documented remission, but this hasn’t been replicated in a controlled trial. The Blades RCT found no cold-specific effect. Cold exposure may help manage symptoms-it is not a cure.
• Cold plunges are as effective as medication. We don’t know this yet. The neurochemical overlap (norepinephrine, dopamine) is real, but equivalence to medication has never been tested in a head-to-head trial. Making this claim is irresponsible and potentially dangerous.
• Cold plunges always reduce cortisol. They increase cortisol acutely during immersion. The reduction comes hours later and with regular practice. Someone doing their first-ever cold plunge will experience a stress response, not immediate calm. Misleading claims about instant cortisol reduction set people up for disappointment.
• The dopamine increase is 250% and that’s like a drug. The 250% figure comes from a 1-hour immersion at 14°C (Šrámek, 2000). A typical 2-5 minute plunge almost certainly produces a smaller dopamine increase. Using the 1-hour figure without context is misleading.
• Everyone with anxiety should do cold plunges. Cold exposure is a physiological stressor. For some people with anxiety especially those with panic disorder or trauma responses to loss of control the cold shock response may trigger panic, not calm. Individual response varies significantly.

Frequently Asked Questions

Sources

Medical Disclaimer: This content is for informational purposes only and does not constitute medical or mental health advice. Cold water immersion is not a substitute for professional treatment for anxiety, depression, or any mental health condition. If you are experiencing a mental health crisis, contact Lifeline or Beyond Blue.