Can a Sauna Give You Super Sperm? Bryan Johnson Thinks So

So...Does Sauna Hurt or Help Sperm?

Traditionally, we’ve heard heat is bad news for sperm and for good reason. Studies show that regular sauna use can temporarily lower sperm count and motility. The body needs cooler temps for sperm production, which is why the testes naturally sit outside the body. In one clinical study, men who used a sauna twice a week for three months saw measurable drops in sperm health (though things bounced back after they stopped).

But Bryan’s approach flips the script. Instead of avoiding the heat, he embraced it - with a side of cold.

Posted 9/9/25

Sauna, without ice on the boys, devastated my fertility markers. If you sauna, ice up.

Posted: 8/29/25

I sacrificed my fertility for this message:
ice your balls in the sauna

After icing improved my fertility markers,
I removed the ice to validate

The boys suffered. More than we initially thought.
Here’s my latest results explained.

0/ Results from sauna experiment

27 daily sauna sessions with ice on balls:
+ total motile count ↑ 57%
+ motility ↑ 16%,
+ total count ↑ 43%

2 weeks without icing (15 sauna sessions with full heat on balls)

my boys’ motility decreased, counts unaffected
total motile count ↓ 54%
motility ↓ 57%
total count ↑ 6%

direct hit to motility and total motile count due to mature sperms in storage (sperm is stored for a couple weeks between full maturation and ejaculation in the Epidimysis).

1/ One week post re-icing: misleading partial recovery (values compared to pre-sauna baseline)
total motile count ↓2%
motility ↓ 34%
total count ↑ 56%

4 weeks post re-icing: 2nd wave of heat effects: large drop in count, motility.
total motile count ↓ 56%
motility ↓ 50%
total count ↓ 9%

Latent hit to counts and motility:
heat damages early spermatogenesis (meiosis) and later sperm maturation (morphological changes, tail formation, and cytoplasmic loss) leading to a reduction in sperm count and motility.

The effect is latent because the "faulty batches" from heat exposure with fewer total and motile sperm are only apparent in test after being stored for a couple weeks in the epididymis.

3/ Full recovery is anticipated within a complete semen generation cycle (spermatogenesis cycle), approx 10 weeks.

Direct experiments on dry sauna and fertility markers haven't been reported, but clinical studies have shown the time-resolved effects of transient (localized heat to the testicles) or sustained (fever) hyperthermia on these markers. This aligns with my observations.

Specifically:
Transient hyperthermia (testicular warming at 43°C for 30 min) led to a continued decrease in sperm count and motility for up to 4 weeks after the daily heat exposure ceased.

A case report indicated a significant reduction in total sperm counts on days 15, 37, and 58 post-fever (though fever's impact doesn't directly compare to transient heat exposure).

Based on these studies, my fertility markers have now reached their lowest point after 2 weeks of unprotected sauna use. I expect a significant recovery within the next month, with complete recovery projected within 6-8 weeks (up to 10 weeks post-heat exposure).

Posted: 7/23/25

Icing your boys in the sauna is a good idea.

Experiment #1:
+ sauna icing the boys improved fertility markers

Experiment #2:
+ no ice devastated fertility markers

Experiment #3:
+ icing again is healing the harm

My results explained and what to do:

4/ I am measuring again in 2 weeks and report on continued recovery

I expect my motile count and motility to continue recovering over the next 2-4 weeks and back to the previous peak achieved following 27 sessions. This is based on:

+ Relative recovery already achieved in 1 week
+ No reduction in total sperm count and concentration,

Though this is not guaranteed since some evidence points at longer and non-linear recovery:

+ Transient hyperthermia (testicular warming at 43°C for 30 min) showed continued drop in sperm count and motility for up to 4 weeks post termination of daily heat exposure. ref
+ A case report showed significant decrease in total sperm counts on days 15,37, and 58, post-fever (keeping in mind fever does not compare well with transient heat exposure) 

Morphology will likely take longer to recover up to 2-3 months.

Several studies following heat exposure or fever indicated that morphology markers only recovered after a complete spermatogenic cycle (75 days).

Posted: 7/15/25

Ppl asking for my icing protocol.
+ ice the boys during sauna
+ use a non-toxic, reusable ice pack material
+ I wear cotton boxers and shorts
+ place ice packs in-between boxers/shorts
+ keep in place for the entire session

Posted: 7/10/25

Sauna heat devastated my swimmers.
Seems icing the balls is a good idea.

No ice protection on the boys:
+ 54% drop in motile count
+ 57% drop in motility
+ 55% drop in normal morphology

Conversely, my fertility markers improved from my pre-sauna baseline after 27 sessions with ice on the boys:

+ total motile count ↑ 57%
+ concentration ↑ 26%
+ motility ↑ 16%,
+ morphology ↑ 15%

This aligns with the evidence. Human testes operate 2-4°C cooler than core temp. Even a +2°C rise (from sauna, hot tubs, laptops, etc.) can derail spermatogenesis for 74-days, the length of a full spermatogenic cycle.

What studies show:

+ A single sauna or hot bath at 80-90 °C can drop progressive motility 40-60% two months later.

+ Scrotal cooling devices used in varicocele (overheated testicles from enlarged veins) treatment restore sperm health within 90 days.

A future question we want to address: did my sperm biomarkers improve because of the combination of sauna and ice pack? Or would an ice pack alone deliver similar results?

My sauna protocol is 20 min daily at 200°F.

Posted 7/3/25

Iced the boys for the first 23 sessions of sauna. Fertility markers dramatically improved.

Have now removed the ice and will be testing fertility markers again next week.

Will let you know.

Posted 6/19/25

A surprising outcome: my fertility health improved by 31% after 21 days of sauna.

Didn’t expect that to happen.

Sauna is not known to improve fertility health. Perhaps it was the icing of my boys?

Protocol:
+ Dry sauna. Temperature: 200 °F (93° C)
+ Daily, 20-min sessions
+ Ice pack on groin area

The result:
My highest numbers to date:
+ Total Motile Count: 240 million (6x fertility baseline)
+ Concentration: 149 million/mL
+ Motility: 53%
+ Morphology: 11% normal
+ Volume: 3.04 mL
+ Total Count: 453 million

Posted: 6/2/25

We’re used to seeing the sauna and cold plunge as a power duo for recovery, but tech entrepreneur and human performance experimenter Bryan Johnson just added an unexpected twist: fertility gains.

In a recent tweet, Bryan shared:

“21 sessions at 20 min, 200°F sauna dramatically improved my fertility health. I iced the boys to protect them, didn’t anticipate that markers would improve.”

Yes, you read that right. He used high-heat sauna sessions while literally icing his groin to safeguard sperm health. And the results? Better fertility markers.

Icing the Boys: Smart or Just Savage?

By using targeted cold exposure (aka ice packs) during high-heat sauna sessions, Bryan may have found a workaround. The cold likely protected testicular temperature, while the sauna delivered its usual benefits: detoxification, circulation, stress reduction, and cardiovascular support.

And if you’re thinking, “There has to be a better way than holding an ice pack in the sauna…” - you’re in luck.

There is.

It’s called vasectomy recovery underwear, and yes, you can absolutely wear them in the sauna. Designed to hold ice packs exactly where you need them, they might just be Bryan Johnson - approved biohacking gear for the rest of us.

What This Means for You

At Plunge, we’re big fans of smart recovery routines. That means listening to your body, dialing in your protocols, and testing what works for you. If fertility is part of your health goals, consider these tips:

• Be mindful of heat exposure - especially duration and frequency.

• Explore contrast therapy (hot sauna + cold plunge) to maximize benefits while minimizing downsides.

• If you’re concerned about sperm health, consult your doctor before locking in a new sauna schedule.

Bottom line: Heat can stress the system - but when paired with cold and intention, it might actually help the body recalibrate in surprising ways. Bryan’s story is a nudge to keep exploring the edge of what’s possible. Just don’t forget the ice.