Diving In: What Science Says About Cold Plunges and Ice Baths

Cold water immersion (CWI), also known as cold plunging or ice baths, has surged in popularity, propelled by athletes, wellness enthusiasts, and social media. This ancient practice, which involves intentionally exposing the body to cold water for therapeutic reasons, is now undergoing rigorous scientific examination. But beyond the anecdotal buzz, what does the latest research actually say about its benefits and risks?

The Claimed Benefits: A Closer Look

Many proponents suggest CWI can accelerate muscle recovery, reduce inflammation, enhance mood, and boost immunity. Here’s a breakdown of the evidence:

• Muscle Recovery and Soreness:

  • Some evidence indicates that ice baths might reduce delayed onset muscle soreness (DOMS) and perceptions of fatigue after exercise.
  • Meta-analyses have shown CWI can speed up recovery of physical function and reduce post-exercise inflammation in athletic contexts.
  • For acute exercise-induced muscle damage, specific protocols of cold water immersion have shown effectiveness:
    • Medium-duration, low-temperature CWI (10–15 minutes at 5°C–10°C) was found most effective for biochemical markers of muscle damage (CK) and neuromuscular recovery (jump performance).
    • Medium-duration, medium-temperature CWI (10–15 minutes at 11°C–15°C) was most effective for alleviating muscle soreness (DOMS).
  • However, a 2025 study found no acceleration of recovery from exercise-induced muscle damage in women after cold or hot water immersion.

• Mental Health and Well-being:

  • Many users report a profound sense of well-being, improved mood, reduced anxiety, and enhanced mental resilience after CWI.
  • The neurochemical basis is plausible, with increases in norepinephrine, dopamine, and endorphins contributing to feelings of exhilaration and focus.
  • A 2025 systematic review and meta-analysis of over 3,000 participants found a statistically significant reduction in perceived stress, but this effect was time-dependent, observed 12 hours after cold exposure. No immediate, 1-hour, 24-hour, or 48-hour effects on stress were noted.
  • Contrary to popular belief, the same meta-analysis found no significant effect of CWI on measures of mood.
  • There was evidence for improvements in participants’ overall quality of life and sleep quality. However, the improvements in quality of life were no longer significant after 90 days in one study, raising questions about participant compliance.
  • The sense of mastery and control from enduring cold stressors may enhance self-efficacy and promote personal growth, which are linked to mental well-being and resilience.
  • The communal aspects of group-based CWI might also foster positive social interactions.

• Metabolic Health and Weight Management:

  • The claim that cold plunges help with fat loss is popular, stemming from the body’s need to increase its metabolic rate to stay warm.
  • However, current scientific evidence for CWI leading to significant fat loss is considered weak or largely anecdotal. The number of calories burned is likely modest and may not contribute meaningfully to weight loss.

• Immunity:

  • While meta-analysis showed no significant effects on immune function immediately or 1 hour post-CWI, one study suggested longer-term benefits with a 29% reduction in sickness absence among participants who took cold showers over 30 days. However, this study also noted no significant difference in the number of illness days reported.

The Risks and Important Considerations

Despite the potential benefits, cold plunges carry risks, and they aren’t for everyone:

• Physical Risks:

  • The rapid change in temperature can lead to a sudden physiological response, including cold shock.
  • Risks include hypothermia and cardiovascular strain. For those with underlying conditions, a healthcare provider should be consulted.
  • Always ensure all equipment is unplugged before entering a cold plunge, even low-voltage DC pumps, to prevent electrical hazards.

• Muscle Growth and Training Adaptations:

  • A significant concern is that CWI, especially when used immediately after resistance training, may blunt desirable training outcomes.
  • It can reduce blood flow to muscles, limiting their ability to absorb protein and recover, which could undermine muscle growth.
  • A 2024 meta-analysis concluded that CWI immediately after resistance training might blunt muscle hypertrophy, though the quality of underlying studies was fair to poor.

• Inflammation:

  • Paradoxically, CWI can cause a significant increase in inflammation immediately and 1 hour after exposure, suggesting an acute inflammatory response.

• Safety in Public Settings:

  • Cold plunge tanks in gyms, spas, and wellness centers face hazards like waterborne pathogens, slips and falls, and suction/entrapment risks.
  • While cold temperatures inhibit some microbial growth, they can also lower disinfectant effectiveness. Therefore, recirculating filtration and automatic disinfection systems are crucial, possibly requiring higher disinfectant residuals or secondary treatments like UV or ozone.

• Personal Aversion and Coercion:

  • If cold water makes you miserable or causes panic, it’s advised to stop. Your body may not adapt, and it might not be for you.
  • Coercion or social pressure (especially for children) to stay in longer is not recommended. The practice should be entered and exited by individual volition.

The Need for More Research

Despite the growing public interest and widespread claims, there is currently limited high-quality evidence on the broad health impacts of CWI in the general population. Most research has focused on short-term effects in young, healthy, male athletes, which limits the applicability of findings to women, older adults, and individuals with different health statuses.

Future high-quality randomized controlled trials (RCTs) are needed to:

• Examine long-term effects of consistent CWI practices.
• Include larger and more diverse samples, specifically involving women and individuals with various health conditions.
• Investigate optimal protocols for temperature, duration, and frequency of exposure to understand dose-response relationships.
• Clearly define and measure a diverse range of outcomes, including behavioral, physical, mental health, and cognitive impacts using validated measures.
• Closely examine safety and participant experience, including adverse events and adherence factors.

The Bottom Line

If you enjoy cold plunges and find personal benefits, and you’re healthy without contraindications, feel free to continue. However, it’s crucial to approach CWI with caution and realistic expectations, understanding that many widely purported benefits still lack robust scientific backing, especially for the general population. Always prioritize your safety and consult with a healthcare professional if you have any health concerns.