VoltraIce baths and cold plunges: do they help recovery?
After hard exercise, sitting in cold water eases muscle soreness and helps you feel recovered the next day [1] [2]. Done regularly straight after strength training, though, it can blunt gains in muscle and strength [3] [4], and the evidence for mood, immunity and metabolism is thin [5] [6]. The sudden cold spikes heart rate and blood pressure [7], and the British Heart Foundation advises people with a heart condition to talk to their doctor before cold-water swimming [8].
What the studies mean by cold
In the research, cold-water immersion usually means sitting in water below 15 °C for about 10 to 20 minutes after exercise, immersing the body and limbs, or just one limb [3] [1]. An earlier review picked 11 to 15 °C for 11 to 15 minutes as the best protocol, but on fewer than four studies per comparison [2]. Interest has grown fast: one review notes that ice-bath sales on Amazon went from under 1,000 units in November 2022 to over 90,000 a year later [5].
Soreness and feeling recovered
A Cochrane review of 17 small trials, 366 people in all and of low quality, found some evidence that cold water eases the muscle soreness that builds up after exercise, compared with resting, from one to four days afterwards [1]. Most of those trials didn't actively check for side effects [1].
A 2022 meta-analysis of 52 studies found that after high-intensity exercise, cold water improved muscle soreness and how recovered people felt 24 hours later, along with muscular power and creatine kinase, a blood marker of muscle damage. It didn't speed the recovery of strength, and after eccentric (muscle-lengthening) exercise it helped only muscular power [2]. In a 2024 meta-analysis, cold water also sped up the return of heart rate variability after exercise; it was the only recovery method with a clear effect [9].
Regular ice baths can blunt gains from lifting
In a 12-week trial, 21 active men strength-trained twice a week and after each session either sat with their legs in 10 °C water up to the waist for 10 minutes, or cycled easily for 10 minutes. Muscle mass and strength rose more in the cycling group [10]. The trial and three meta-analyses side by side:
| Study | Who | What it found |
|---|---|---|
| Roberts 2015, trial | 21 active men, 12 weeks | Muscle mass and strength rose more with easy cycling than with cold water [10] |
| Malta 2021, meta-analysis | 8 studies | Smaller strength gains; no effect on endurance gains [4] |
| Grgic 2023, meta-analysis | 10 studies, 92% men | Slightly smaller strength gains; not significant with whole-body immersion [11] |
| Piñero 2024, meta-analysis | 8 studies | May slightly reduce muscle growth; studies of fair to poor quality [3] |
In these studies the cold water came straight after lifting [3]. Endurance training looks different: regular cold water didn't change endurance performance gains [4], and a 2024 review notes little or no harm to endurance adaptations [3].
Mood, immunity and metabolism
A 2025 review of 11 randomised trials in healthy adults found that cold water briefly raised markers of inflammation, lowered stress 12 hours later but not at other times, and improved sleep quality and quality of life, but not mood [5]. The evidence is thinner than its 3,177 participants suggest: 3,018 of them (95%, calculated) came from one cold-shower trial, so the other 10 trials had 159 people between them (calculated), all men, and the sleep and mood results each came from a single study [5].
That cold-shower trial, in 3,018 Dutch adults, had people end their usual warm shower with 30 to 90 seconds of the coldest water available, every day for a month. They reported 29% fewer days off work sick, but no fewer days of illness; the results were self-reported, and people with serious heart or lung disease were excluded [12].
Cold does raise noradrenaline and dopamine: in young men who sat in 14 °C water up to the neck for an hour, noradrenaline rose by 530% and dopamine by 250% [13]. An hour is far longer than the 10 to 20 minutes usual in recovery studies [3], and the study reported hormones, not mood [13].
On metabolism, cold does switch on brown fat and raise energy use, but a 2022 review of 47 trials found the studies small and judged cold an unlikely lasting way to treat obesity; changes in energy use didn't bring big changes in weight [6]. A 2026 review of six mostly one-off studies, only two of them with full-body cold water, found four reporting better insulin sensitivity and one more insulin resistance, and called using cold water as an add-on treatment for insulin resistance premature [14]. A 2017 review of cold-water immersion concluded that some of the claimed benefits still rest on anecdote [15].
Safety
The US National Weather Service warns: "Cold water can cause a sudden spike in heart rate and blood pressure. This increase can cause heart failure and stroke for vulnerable people." [7] The first gasp and fast breathing last for the first 2 to 3 minutes or more and raise the risk of drowning; they can be set off by water as warm as 25 °C, and cold shock at 10 to 15 °C can be as severe as at 2 °C [7].
Heart rhythm is the other concern. In lab tests on young, healthy volunteers, rhythm disturbances showed up in about 2% of immersions with the head out and normal breathing, but in 62 to 82% when they went under and held their breath; most caused no symptoms [16]. The researchers propose that the clash between the cold-shock and diving reflexes may explain some sudden deaths in cold water, particularly in people with long QT syndrome or ischaemic heart disease [16].
The British Heart Foundation says cold shock raises heart rate and blood pressure and can leave you short of breath, that cold water raises stress hormones and the risk of abnormal heart rhythms, and that people with a heart condition should talk to their doctor or nurse before cold-water swimming [8]. We found no advice on ice baths or cold plunges from Gulf health authorities, including Saudi Arabia's health ministry and food and drug authority, or those of the UAE, Kuwait and Qatar. Cooling someone with heat stroke is a different matter; see our guide to exercising in the heat.
In Voltra
Home shows a Recovery reading from 0 to 100. From Apple Health data, it compares your heart rate variability (HRV) and resting heart rate with your own 30-day baseline. Voltra doesn't log ice baths or sauna sessions, so it won't link a change in that reading to a plunge. Our Apple Health guide explains what Voltra reads.
Frequently asked
Do ice baths help recovery?
For soreness, a little: cold water after hard exercise eased muscle soreness and helped people feel recovered the next day, but it didn't speed the return of strength. Most trials were small.
Do ice baths stop muscle growth?
Used regularly straight after strength training, they can reduce gains. In a 12-week trial, muscle mass and strength rose more with easy cycling than with 10 minutes in 10 °C water, and meta-analyses found smaller gains in muscle and strength.
Is a cold plunge good for mood or immunity?
The evidence is thin. A 2025 review found lower stress 12 hours after cold water but no effect on mood, and the main immunity finding, 29% fewer sick days, came from one self-reported cold-shower trial.
Who should avoid ice baths?
Sudden cold spikes heart rate and blood pressure. The British Heart Foundation advises people with a heart condition to talk to their doctor before cold-water swimming, and researchers flag long QT syndrome and ischaemic heart disease as possible risks for dangerous heart rhythms.
Sources
- Bleakley C, McDonough S, Gardner E, et al. (2012). Cold-water immersion (cryotherapy) for preventing and treating muscle soreness after exercise. Cochrane Database Syst Rev CD008262. Abstract. 17 small trials, 366 people.
- Moore E, Fuller JT, Buckley JD, et al. (2022). Impact of Cold-Water Immersion Compared with Passive Recovery Following a Single Bout of Strenuous Exercise on Athletic Performance in Physically Active Participants: A Systematic Review with Meta-analysis and Meta-regression. Sports Med 52(7):1667–1688. Abstract and introduction. A co-author held a football club grant to study cold-water immersion.
- Piñero A, Burke R, Augustin F, et al. (2024). Throwing cold water on muscle growth: A systematic review with meta-analysis of the effects of postexercise cold water immersion on resistance training-induced hypertrophy. Eur J Sport Sci 24(2):177–189. Abstract and introduction. 8 studies.
- Malta ES, Dutra YM, Broatch JR, Bishop DJ, Zagatto AM (2021). The Effects of Regular Cold-Water Immersion Use on Training-Induced Changes in Strength and Endurance Performance: A Systematic Review with Meta-Analysis. Sports Med 51(1):161–174. Abstract. 8 studies.
- Cain T, Brinsley J, Bennett H, et al. (2025). Effects of cold-water immersion on health and wellbeing: A systematic review and meta-analysis. PLoS One 20(1):e0317615. Abstract, results and introduction. 11 trials.
- Perez LC, Perez LT, Nene Y, Umpierrez GE, Davis GM, Pasquel FJ (2022). Interventions associated with brown adipose tissue activation and the impact on energy expenditure and weight loss: A systematic review. Front Endocrinol 13:1037458. Abstract. 47 trials; two authors declare industry fees or research funding.
- US National Weather Service (NOAA). Cold Water Hazards and Safety. Cold shock, heart and blood pressure.
- British Heart Foundation (2023). Cold water swimming: is it bad for your heart? Heart Matters magazine. Advice for people with heart conditions.
- Laborde S, Wanders J, Mosley E, Javelle F (2024). Influence of physical post-exercise recovery techniques on vagally-mediated heart rate variability: A systematic review and meta-analysis. Clin Physiol Funct Imaging 44(1):14–35. Abstract. 24 studies.
- Roberts LA, Raastad T, Markworth JF, et al. (2015). Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. J Physiol 593(18):4285–301. Abstract and methods.
- Grgic J (2023). Effects of post-exercise cold-water immersion on resistance training-induced gains in muscular strength: a meta-analysis. Eur J Sport Sci 23(3):372–380. Abstract. 10 studies.
- Buijze GA, Sierevelt IN, van der Heijden BC, Dijkgraaf MG, Frings-Dresen MH (2016). The Effect of Cold Showering on Health and Work: A Randomized Controlled Trial. PLoS One 11(9):e0161749. Abstract and methods. 3,018 adults in the Netherlands.
- Srámek P, Simecková M, Janský L, Savlíková J, Vybíral S (2000). Human physiological responses to immersion into water of different temperatures. Eur J Appl Physiol 81(5):436–42. Abstract.
- Gaydos J, Maravich B, Nolan D, Hartwell M (2026). Cold water exposure therapy and effects on insulin: a scoping review. J Osteopath Med. Abstract. Six studies; published online 25 September 2026.
- Tipton MJ, Collier N, Massey H, Corbett J, Harper M (2017). Cold water immersion: kill or cure? Exp Physiol 102(11):1335–1355. Abstract. Narrative review.
- Shattock MJ, Tipton MJ (2012). 'Autonomic conflict': a different way to die during cold water immersion? J Physiol 590(14):3219–30. Review; the authors present autonomic conflict as a hypothesis.
Sources checked on 30 September 2026.
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