Blue Balls Co.

Editorial

The sauna guide

Whole body hot. One place cold. How we do it - and how the people who study it do it.

Last reviewed 12 September 2026 · Sources checked 12 September 2026

Man walking a misty pier after the sauna, The Wrap over his shoulders
Man stepping out of the wooden sauna by the lake while a friend holds the sauna hat
Red wooden sauna on a rocky shore by the pier, blue towel on the railing

The protocol

Bryan Johnson sits 20 minutes at 93 degrees every day with ice on his groin, ice on his head and a litre of water afterwards. We translated the idea into Swedish sauna reality - 80–90 degrees, rounds with cool-downs - and put an evidence grade on every step.

Bryan · The research · Us

What Bryan does

  • 93 degrees, 20 minutes
  • Every day
  • Ice on head and groin
  • A litre of water afterwards
  • n=1, his own measurements

What the research says

  • 80–90 degrees, over 19 minutes
  • 4–7 sessions a week in Finnish data (correlation)
  • Avoid heat if you are trying to conceive
  • Active cooling is not shown
  • Alcohol is the real risk

What we do

  • 80–90 degrees, 2–3 rounds
  • 2–4 sessions a week
  • Hat for comfort, cold pack in a fabric pocket
  • Cool down between rounds
  • Water with a little salt afterwards
  1. 01Prepare
    A/B

    Drink 300–500 ml of water 30–60 minutes before. No alcohol.

    Why: You lose 0.5–1 litre per session, and alcohol is the dominant risk factor.

  2. 02Your head
    C

    Wool hat or towel. Going all in: a cold pack on top of the towel.

    Why: The air is hottest at head height and hair dries out at 80–100 degrees. Comfort - not medicine.

  3. 03The groin
    B / D

    Cold pack in an insulated pocket. Never against bare skin. Remove at pain or numbness.

    Why: Testicles want around 34 degrees. Whether it protects sperm has not been shown - but it feels good when the rest of you is at 90.

  4. 04Sauna
    B

    2–3 rounds of 10–15 minutes at 80–90 degrees, with cool-downs between. 20+ minutes of heat in total.

    Why: Finnish data: sessions over 19 minutes are linked to lower risk than short ones.

  5. 05Cool down
    C

    Lukewarm or cold shower, lake or outdoor air between rounds. Stand up slowly. Heart condition? Avoid abrupt cold plunges.

    Why: Finnish practice. Contrast bathing has weak evidence for anything beyond feeling good.

  6. 06Shower and skin
    A

    Rinse lukewarm, pat dry, moisturise. Scrub at most once a week, only on intact skin.

    Why: Hygiene and skin. Nothing else.

  7. 07Rehydrate
    A/B

    Weigh yourself. 1.25–1.5 litres per kilo lost, with a little salt and something potassium-rich.

    Why: Salt helps the body hold on to the fluid.

  8. 08Frequency
    B

    2–4 sessions a week.

    Why: Dose-response in the Finnish studies.

This is what we use ourselves.

Step 2 – The Lid. Step 3 – The Icebox. Step 5 – The Steps. Step 6 – The Scrub, The Wrap.

See the gear

Cold pack safety

  • Never place the cold pack directly against skin - use the pocket or a fabric layer.
  • Maximum 15–20 minutes at a time.
  • Remove immediately if you feel pain or numbness, or if the skin turns white.
  • Do not use with reduced sensation or circulation problems.
  • Not for children.
The research behind fluid and salt

How the people who study it do it

Strikingly, they all land in roughly the same place: 80 degrees, 20 minutes, several times a week, water, no alcohol.

Jari Laukkanen

Kardiolog, forskaren bakom de finska studierna

Temperature:
80–90 °C
Length:
Minst 20 min
Frequency:
4–7 ggr/vecka

Betonar att resultaten gäller traditionell bastu – och att det är samband, inte bevisad orsak.

Andrew Huberman

Neuroforskare, Stanford

Temperature:
80–100 °C
Length:
5–20 min per runda
Frequency:
2–3 ggr/vecka eller mer

Tar upp kylpack i bastun som ett rimligt sätt att mildra värmens effekt, och betonar rikligt med vätska.

Rhonda Patrick

FoundMyFitness

Temperature:
~79 °C
Length:
20 min
Frequency:
4–7 ggr/vecka

Varnar för över 93 grader och rekommenderar elektrolyter efteråt.

Peter Attia

Läkare

Temperature:
~80 °C torrbastu
Length:
Minst 20 min
Frequency:
Minst 4 ggr/vecka

Tydlig med att underlaget är samband, inte bevis.

Michael Eisenberg

Urolog, Stanford

Temperature:
-
Length:
-
Frequency:
-

Om värme, kylpack och pungen: rimligt att kyla, men isolera alltid mot huden.

Bryan Johnson

Blueprint, n=1

Temperature:
93 °C
Length:
20 min
Frequency:
Dagligen

Is på pung och huvud, cirka en liter vätska. Egna mätningar på en person – anekdot, inte evidens.

Finsk praxis

Finska Bastusällskapet, Visit Finland

Temperature:
70–90 °C
Length:
Rundor à 10–15 min
Frequency:
Flera ggr/vecka

Vatten på stenarna (löyly), björkris, nedkylning mellan rundorna, ingen alkohol.

If you are trying to conceive

This is the question we get most often. The honest answer:

  1. 01Heat temporarily lowers sperm count and motility. Two sauna sessions a week for three months was enough to more than halve the values in healthy men - and everything was normal again six months later (Garolla 2013).
  2. 02Count on three months. That is a full sperm cycle. What you do today shows up in a sample in two to three months.
  3. 03The standard clinical advice (Nordic IVF, Kry, Mayo Clinic): avoid sauna, hot baths, laptops on your lap and seat heating during the three months you are trying. If you still want to go - go rarely, briefly and cooler, and keep the scrotum cool.
  4. 04Cooling is reasonable but not proven. No study has tested a cold pack in the sauna on healthy men. Bryan Johnson's own measurements are interesting, not proof.
  5. 05Supplements are not the answer. A study of 2,372 couples found no effect of zinc and folic acid.
  6. 06Talk to your clinic if you are being investigated. Swedish andrologists point out that there is still no evidence that lifestyle changes improve fertility (Läkartidningen 2022) - but avoiding heat is free and risk-free.

Read on

The evidence: heat and fertility

Who should not use a sauna - and when

  • Alcohol. No. The vast majority of sauna deaths involve alcohol.
  • Fever, infection, recent heart attack, unstable angina or uncontrolled high blood pressure - stay out. Stable heart disease is not a barrier according to Swedish cardiologists, but ask your doctor.
  • Pregnancy and children - shorter, cooler, never alone, and ask a clinician.
  • Medication affecting blood pressure, sweating or fluid balance (beta blockers, diuretics and others) - ask.
  • The most common side effect is dizziness when you stand up: drink, rise slowly, sit down if the room spins.

Cold pack safety

  • Never place the cold pack directly against skin - use the pocket or a fabric layer.
  • Maximum 15–20 minutes at a time.
  • Remove immediately if you feel pain or numbness, or if the skin turns white.
  • Do not use with reduced sensation or circulation problems.
  • Not for children.

Gear

Why each thing is in the protocol. Comfort and tradition - no health claims.

The Lid

Wool insulates, your head sits in the hottest layer of air, and hair dries out at 80–100 degrees (keratin itself is only damaged around 220–250). Tradition from the Russian banya - no study has measured it, and none is needed for it to feel good.

The Icebox

Briefs with an insulated pocket for a cold pack, keeping one area cooler than the rest of you. Comfort and cool. The pack always sits in the pocket, never against bare skin.

The Steps

Slides for the walk between sauna and cold plunge. Hot floors, cold decking, wet changing rooms.

The Scrub

A scrub mitt for skin softened by heat. Once a week at most, never on irritated skin, moisturise afterwards.

The Wrap

A towel that handles getting soaked three times a day and drying in between.

Frequently asked questions

Articles

Blue Balls Co. sells sauna textiles and accessories for comfort. Our products are not medical devices and we make no claims about effects on fertility, semen quality or hormones. The content on this page is a summary of published research and does not replace medical advice - if you have questions about your reproductive health, talk to a clinician. We update the page when the research does. Last reviewed: 12 September 2026.