Cold exposure, sauna, breathwork — what actually does something

Your feed is full of people dunking themselves in ice water, sitting in saunas until they can’t breathe, and doing breathing exercises that look like they’re about to pass out.

But which of these actually does something to your biology? And which ones are just content?

Let’s separate the science from the hype.

Cold exposure (ice baths, cold showers)

What it actually does:

Cold exposure triggers a cascade of biological responses:

Norepinephrine release. Cold water immersion increases norepinephrine by 200-300%. This is your “focus and alertness” neurotransmitter. It’s why you feel sharp after a cold shower — it’s not placebo, it’s chemistry.

Brown fat activation. Your body has two types of fat: white (storage) and brown (burning). Cold exposure activates brown adipose tissue, which burns calories to generate heat. A study in the Journal of Clinical Investigation found that regular cold exposure increased brown fat activity and improved insulin sensitivity [1].

Inflammation reduction. Cold water immersion performed on successive days reduced inflammatory markers (IL-6, CRP) in athletes [2]. But this is dose-dependent — 2-3 minutes at 10-15°C is enough. Longer isn’t better.

What the research says:

  • Cold water immersion (10-15°C, 2-5 minutes) = effective
  • Cold showers (15-20°C, 30-60 seconds) = mild benefit
  • Extreme cold (-100°C cryotherapy) = limited evidence, expensive

The verdict: Works. But the dose matters. 2-5 minutes in 10-15°C water, 2-3 times per week. Not every day. Not for 15 minutes. The goal is a stress response, not hypothermia.

Sauna

What it actually does:

Sauna exposure raises your core body temperature. This triggers:

Heat shock proteins (HSPs). These are cellular repair mechanisms. When your body temperature rises, HSPs activate to repair damaged proteins and protect cells from stress. A review in Cell Stress and Chaperones found that restoring the heat shock response resolved inflammation in chronic disease [3].

Cardiovascular benefits. A narrative review found that regular sauna bathing improved cardiovascular health markers, including blood pressure, arterial stiffness, and endothelial function [4]. The Finnish sauna studies (20+ years of data) show regular sauna use is associated with reduced cardiovascular mortality.

Growth hormone release. Sauna exposure (particularly repeated sessions) increases growth hormone by up to 200-300%. GH supports muscle repair, fat metabolism, and collagen production.

What the research says:

  • Finnish sauna (80-100°C, 15-20 minutes, 2-3x/week) = strong evidence
  • Infrared sauna (50-60°C, 30-45 minutes) = moderate evidence, more accessible
  • Steam rooms = less studied but similar heat stress response

The verdict: Works. The Finnish model (hot, dry, 15-20 minutes) has the most evidence. Infrared is a good alternative if you don’t have access to a traditional sauna.

Breathwork (Wim Hof, box breathing, etc.)

What it actually does:

Breathwork isn’t one thing. There are different techniques with different effects:

Wim Hof Method (hyperventilation + breath holds):

  • Activates the sympathetic nervous system (fight-or-flight)
  • Increases adrenaline and norepinephrine
  • Temporarily suppresses immune response
  • Can reduce inflammation markers

Box breathing (4-4-4-4 pattern):

  • Activates the parasympathetic nervous system (rest-and-digest)
  • Reduces cortisol
  • Improves heart rate variability (HRV)
  • Best for stress management

What the research says:

  • Wim Hof method = interesting but limited large-scale studies. Small studies show reduced inflammatory markers in trained individuals.
  • Box breathing = well-studied, reliable for stress reduction and HRV improvement
  • Diaphragmatic breathing = consistent evidence for anxiety reduction

The verdict: Breathwork works, but it depends on which type. For stress management: box breathing or diaphragmatic breathing. For performance/immune response: Wim Hof method. Don’t do Wim Hof before bed — it’s activating, not calming.

What actually does something (ranking)

Tier 1 — Strong evidence:

  1. Sauna (Finnish style, 2-3x/week) — cardiovascular, heat shock proteins, GH release
  2. Cold water immersion (2-5 min, 10-15°C) — norepinephrine, brown fat, inflammation

Tier 2 — Good evidence: 3. Box breathing / diaphragmatic breathing — stress reduction, HRV improvement 4. Cold showers (30-60 seconds) — accessible entry point, mild benefit

Tier 3 — Limited evidence: 5. Wim Hof method — interesting, needs more research 6. Cryotherapy chambers — expensive, limited evidence over cold water

The protocol that actually works

If you want to do this properly:

Monday/Wednesday/Friday: Sauna (80-90°C, 15-20 minutes) Tuesday/Thursday: Cold water immersion (10-15°C, 2-3 minutes) Daily: Box breathing (5 minutes, morning or evening)

Start slow. Don’t do everything at once. Add one modality per week.

What to skip:

  • Extreme cold exposure (below 5°C) without building tolerance
  • Sauna longer than 20 minutes without experience
  • Wim Hof method if you have anxiety or panic disorder (it can trigger episodes)

The bottom line

Cold exposure, sauna, and breathwork all do something real. But the dose matters. The Finnish sauna model has 20+ years of evidence. Cold water immersion has strong data for inflammation and norepinephrine. Breathwork is reliable for stress management.

Don’t do them because an influencer does them. Do them because the biology makes sense. Start with one. Build from there.

References

  1. van Marken Lichtenbelt WD, et al. Cold-activated brown adipose tissue in healthy men. N Engl J Med. 2009;360(15):1500-1508. https://pubmed.ncbi.nlm.nih.gov/19357406/

  2. de Freitas VH, et al. Effect of Cold Water Immersion Performed on Successive Days on Physical Performance, Muscle Damage, and Inflammatory, Hormonal, and Oxidative Stress Markers in Volleyball Players. J Strength Cond Res. 2019;33(2):502-511. https://pubmed.ncbi.nlm.nih.gov/28277426/

  3. Schroeder HT, et al. Resolution of inflammation in chronic disease via restoration of the heat shock response (HSR). Cell Stress Chaperones. 2024;29(1):1-10. https://pubmed.ncbi.nlm.nih.gov/38309688/

  4. Nagai M, et al. Effects of Bathtub Bathing and Sauna Practices on Cardiovascular and Systemic Health: A Narrative Review. Int J Environ Res Public Health. 2026. https://pubmed.ncbi.nlm.nih.gov/41899724/

This post contains affiliate links. If you purchase through these links, I may earn a small commission at no extra cost to you.

Coming soon

  • The supplement stack that actually helps with perimenopause
  • Why your iron levels matter more than you think
  • Retatrutide: The next weight loss peptide everyone is waiting for