Take the step to enhance your recovery with contrast therapy

Contrast therapy is the latest recovery approach to dominate social media, with the trend already developing into a major social phenomenon, with niche ‘synth clubs’ and shared baths replacing traditional nightlife as a sober, health-focused way of bonding.

Uploading it Heat is often combined with ice bath immersions in a practice known as hot-cold contrast therapy or contrast therapywhich research¹ Emissions can improve post-exercise recovery by reducing muscle damage, fatigue and soreness.

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Contradictory results

Contrast therapy works by promoting vasodilation from heat (thermotherapy) and vasoconstriction from cold (cryotherapy) to create a ‘pumping action’ which helps improve circulation, manage swelling and lymph drainage and remove exercise metabolite¹. The treatment also helps improve joint range of motion¹.

Cycling through vasodilation in the heat and vasoconstriction in the cold, the practice aims to flush out metabolic waste, reduce inflammation and accelerate muscle recovery, making it a favorite with athletes and ‘biohackers’ alike.

Data available² shows that contrast therapy is superior to the use of passive recovery or post-exercise rest, with greater effects among serious and elite athletes subjected to higher training loads.

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Bring on the heat

Studies³ show this Heat therapy can support muscle recovery by increasing blood flow, promoting healing and reducing muscle soreness through mechanisms such as vasodilation and increased expression of heat shock protein (HSP).

Heat therapy is effective when used before exercise to prepare muscles and after exercise to speed recovery, with some research showing that it may be more beneficial than cold therapy immediately after vigorous activity.

There are also potential benefits associated with regular sweating, such as better physical detoxification. The skin is technically the body’s largest organ of elimination, supporting the kidneys and liver by bringing certain toxins to the surface of the skin for removal. However, the contribution of the skin to the removal of toxins is small compared to the kidneys.

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The cold, hard truth

Cryotherapy (especially whole body cryotherapy, or WBC) acts directly on muscles, particularly the extremities, causing vasoconstriction. As the body reacts to the extreme cold, it diverts peripheral blood flow to internal organs.

This promotes the removal of exercise metabolites and other byproducts from muscle tissue, where they travel into the bloodstream and are more efficiently eliminated through the kidneys and liver.

Cryotherapy also works indirectly on the autonomic nervous system (ANS)⁴ and endocrine (hormonal) systems for faster restoration of homeostasis and improvement of function.

Cryotherapy supports recovery primarily by modulating the ANS, shifting it towards a state of rest and recovery. Initial, brief exposure to extreme cold, as in whole-body cryotherapy, is an acute stressor that triggers a fight-or-flight response, which is mediated by a branch of the ANS—the sympathetic nervous system (CNS).

This initial stress triggers the release of stress hormones and neurotransmitters such as norepinephrine and adrenaline, which can lead to a temporary increase in alertness and mood elevation.

The key to the recovery benefit of cryotherapy lies in the subsequent, compensatory responsewhich is a shift to the other branch of the ANS, the parasympathetic nervous system (PNS), which triggers the “rest and digest” state. This heightened parasympathetic response speeds recovery after intense physical exertion.

The indirect impact also comes from the release of powerful hormones that help the recovery and rebuilding process, such as noradrenaline (which helps reduce inflammation)⁴ and testosterone (which enhances strength and anabolism)⁵.

Hormonal benefits of cryotherapy include:

• Increased release of noradrenaline⁴
• Increased testosterone release⁵
• Lowers cortisol levels with prolonged use ⁶

Cold immersion

Without access to a WBC chamber, cold water therapy requires submerging your body in water that is 15°C or colder. This may include ice baths, cold showers, or outdoor swimming in cold or icy climates.

How to prepare an ice bath at home:

1. Add cold water to a tub or large plastic drum, leaving room for ice.
2. Slowly add ice to the water while stirring to distribute the cold evenly.
3. Use a thermometer to make sure the water reaches the desired temperature (7-10°C). This can take about 10-20 minutes.
4. Set a timer: Limit your time in the ice bath to 10-15 minutes to be safe. Use a timer to keep track.
5. Enter slowly: Enter the ice bath gradually, allowing your body to adjust to the cold. Avoid sudden dips.

Added benefits

There is also evidence to suggest so Cryotherapy has a positive impact on your immune systemwhich can also support recovery.

Results from a study⁷ published in the Journal of Applied Physiology showed “that acute cold exposure has immunostimulatory effects” that increase the production of immune cells known as natural killer (NK) cells.

A team of researchers from the University of Portsmouth also found that daily cold showers increased the number of disease-fighting white blood cells⁸.

Other studies have revealed this acute exposure to cold stimulates the production of immune cells, such as natural killer cells. For example, a study⁹ showed that six weeks of six-minute cold water immersions at 14°C, repeated three times a week, improved the immune system.

The researchers found that the cold triggered a “fight or flight” response, which triggered an immune response – a “small, but significant, increase in the proportions of lymphocytes”, which are cells that fight infection.

References

1. Leonardi G, Portaro S, Milardi D, Bonanno F, Sanzarello I, Bruschetta D, Sconza C, Tisano A, Fontana JM, Alito A. Mechanisms and efficacy of contrast therapy for musculoskeletal pain: A scoping review. J Clin Med. 2025 Feb 21, 14(5):1441. doi: 10.3390/jcm14051441. PMID: 40094855; PMCID: PMC11900007.
2. Bieuzen F, Bleakley CM, Costello JT. Water contrast therapy and exercise-induced muscle damage: a systematic review and meta-analysis. PLoS One. 2013 Apr 23;8(4):e62356. doi: 10.1371/journal.pone.0062356. PMID: 23626806; PMCID: PMC3633882.
3. Kim K, Monroe JC, Gavin TP, Roseguini BT. Topical heat therapy to accelerate recovery after exercise-induced muscle damage. Exerc Sport Sci Rev. 2020 Oct;48(4):163-169. doi: 10.1249/JES.0000000000000230. PMID: 32658042; PMCID: PMC7492448.
4. Louis J, Theurot D, Filliard JR, Volondat M, Dugué B, Dupuy O. The use of whole-body cryotherapy: time- and dose-response research on circulating blood catecholamines and heart rate variability. Eur J Appl Physiol. 2020 Aug. 120(8):1733-1743. doi: 10.1007/s00421-020-04406-5. Epub 2020 May 30. PMID: 32474683; PMCID: PMC7340648.
5. Naylor AS, Edwards BJ, Robertson CM. Effects of treatment dose of whole-body cryotherapy on post-match recovery of endocrine and biochemical markers in elite rugby players: An experimental study. Health Sci Rep. 2023 Apr 19;6(4):e1227. doi: 10.1002/hsr2.1227. PMID: 37091363; PMCID: PMC10114078.
6. Lombardi G, Ziemann E, Banfi G. Whole body cryotherapy in athletes: From treatment to stimulation. An updated literature review. Front Physiol. 2017 May 2; 8:258. doi: 10.3389/fphys.2017.00258. PMID: 28512432; PMCID: PMC5411446.
7. Immunological changes in humans during cold exposure: effects of prior warming and exercise. J App Physiol. August 1, 1999. https://doi.org/10.1152/jappl.1999.87.2.699.
8. Habituation of initial responses to cold water immersion in humans: a central or peripheral mechanism? Journal of Physiology (1998), 512.2, pp. 621628 621
9. NK cell activation in subjects exposed to mild hyper- or hypothermic stress. Journal of Interferon Research. Published online: May 4, 2009.