SAUNA, CONTRAST & LONGEVITY
You optimise the heat. The cold. The recovery. Don’t forget the skin.
Sauna, cold plunge and contrast therapy have become part of modern recovery routines. But your skin goes through the entire session with you: heat, sweat, plunge water, shared benches, towels and changing rooms.
This guide explains what your skin encounters during the routine and where a simple skin-defence step can fit.
What happens to your skin during a contrast session?
Heat and cold are usually discussed in terms of performance, recovery and wellbeing, but skin is exposed throughout the session too. Sauna changes skin temperature and sweating, while research has also measured changes in skin hydration, transepidermal water loss and surface pH after sauna exposure.
Then comes the cold plunge, followed by contact with water, towels, benches and changing areas. None of that means sauna or cold plunge is inherently bad for skin. It simply means skin is part of the recovery environment and deserves some attention when the session ends.
A practical heat and cold framework
There is no single sauna or cold-plunge prescription that suits every person or every goal. A practical traditional-sauna starting range is around 15–20 minutes at 80–90°C, with hydration, gradual acclimatisation and individual tolerance taken seriously.
For people already accustomed to cold exposure, a short 1–3 minute plunge can be used as a practical contrast-session framework. That should not be confused with an evidence-based “optimal” recovery dose: cold-water immersion studies use a wide range of temperatures and durations depending on the outcome being studied.
A simple contrast sequence can therefore be:
HEAT → COLD → REST
Experienced users may repeat the sequence if comfortable. Longer or more extreme exposure is not automatically better.
What should you do with your skin after sauna and cold plunge?
Once the heat-and-cold portion is finished, the skin routine can stay simple:
- Rinse. Use fresh, lukewarm water to remove sweat, plunge water and surface residue.
- Clean. Use a mild cleanser on wet skin and follow that product’s own instructions. Avoid aggressive scrubbing.
- Dry. Pat the skin with your own clean towel rather than rubbing hard.
- Protect. Add a simple skin-defence step to clean, dry skin.
- Recover. Continue with the moisturising or barrier care that suits your skin.
That gives the routine a clear sequence without turning it into an elaborate skincare ritual.
Where does hypochlorous acid fit?
Hypochlorous acid, often shortened to HOCl, can be delivered as a lightweight fine mist. Within the BLOK routine, it sits after rinsing, cleansing and drying.
BLOK Skin Defence Spray is a 200ppm hypochlorous acid fine mist. Spray onto clean skin until evenly wet and allow it to air dry naturally.
It is intended as one practical step in the routine, not a replacement for showering, cleansing, moisturising or professional skincare advice.
Common questions
How long should you stay in a sauna?
Around 15–20 minutes is a practical starting range used in published sauna guidance, but temperature, experience, health status and individual tolerance matter. Hotter or longer is not automatically better.
Should you shower after sauna and cold plunge?
Rinsing or showering afterwards is a sensible way to remove sweat, plunge water and surface residue. Fresh lukewarm water, gentle cleansing and a clean towel are a straightforward sequence.
Should you rinse before using cleanser after sauna?
Yes. Rinsing first removes sweat and surface residue before cleanser is applied. Use a mild cleanser and follow its own contact-time instructions rather than applying a universal timing rule.
Can hypochlorous acid be used after sauna?
Within the BLOK routine, Skin Defence Spray sits after rinsing, cleansing and drying as the skin-defence step. It is a 200ppm hypochlorous acid fine mist and is allowed to air dry naturally.
Is this a longevity protocol?
Sauna and cold exposure are commonly used within modern recovery and longevity routines, but BLOK does not claim that Skin Defence Spray increases lifespan or improves longevity. This article focuses on the skin-care sequence that can sit alongside those routines.
Safety
This is a practical general framework, not personalised medical advice. Heat and cold exposure are not appropriate for everyone. Do not chase extreme temperatures or durations, stop if you feel unwell, and seek appropriate medical advice before starting heat or cold exposure if you have a relevant health condition, are pregnant, take medication that affects temperature regulation or have concerns about your suitability.
Sources & further reading
The guidance above is informed by peer-reviewed research, dermatology guidance and published heat-and-cold protocols. The sources are separated below so that research evidence is not presented as equivalent to general practice guidance.
Peer-reviewed evidence
- Kowatzki et al. Effect of regular sauna on epidermal barrier function and stratum corneum water-holding capacity in vivo in humans: a controlled study. Dermatology. 2008.
- Machado et al. Can Water Temperature and Immersion Time Influence the Effect of Cold Water Immersion on Muscle Soreness? A Systematic Review and Meta-Analysis. Sports Medicine. 2016.
- What Parameters Influence the Effect of Cold-Water Immersion on Muscle Soreness? An Updated Systematic Review and Meta-Analysis.
- The effect of cold water immersion on the recovery of physical performance revisited: A systematic review with meta-analysis.
- Bleakley & Davison. What is the biochemical and physiological rationale for using cold-water immersion in sports recovery? A systematic review.
Dermatology guidance
- American Academy of Dermatology: gentle cleansing guidance.
- American Academy of Dermatology: moisturising and dry-skin guidance.
Protocol and practice references
- Blueprint: published sauna guidance.
- Huberman Lab with Dr Susanna Søberg: heat and cold exposure discussion.
SKIN DEFENCE FOR MODERN EXPOSURE.
