I Did the Frozen Lake Thing So You Don’t Have To
What I learned about cold plunges, cortisol, and cycle syncing - in a hole in northern Finland carved into the ice.
Ancient rituals keep getting repackaged as biohacking trends. Cold plunges are the perfect example - what was once a seasonal, communal reset is now a daily discipline with a stainless steel price tag.
Here’s what happened when I took the plunge - literally - and what the science (and my nervous system) had to say about it.
And if you couldn’t care less about cold therapy and just want my favorite spots to eat, stay, and defrost in Finland- scroll to the bottom.
Cold Exposure: Why Temperature Isn’t the Whole Story
Cold therapy isn’t new. For centuries, cultures across Scandinavia and Eastern Europe have used thermal contrast—saunas followed by snow rolls, banyas paired with ice baths—not for optimization, but for rhythm, regulation, and ritual.
I grew up in Poland, where rolling in the snow after a sauna wasn’t a wellness flex - it was mandatory family bonding. My dad made us do it every week. I hated it. I thought it was medieval. I’d scream, sprint inside, and swear I was dying. Spoiler: no one cared.
So years later, when I found myself standing on a frozen lake in Finland (Kusamo to be specific) - preparing to plunge into a man-made hole in the ice - I realized I’d come full circle. This time, I wasn’t forced. I chose it and here is what I learned
My Frozen Lake Revelation
It was one of those startup-meets-wellness bonding moments. I was with the founder of a hormonal health company, and plunging into a lake that was otherwise solid ice except for a single carved-out hole felt both ceremonial and absurd.
The air was so cold my Celine boots froze solid before I could take them off - and never recovered. I should’ve taken that as a sign.
But I jumped anyway. And as my body jolted underwater, one thought cut through the dopamine rush:
This is the worst thing I could be doing for my body right now.
Because on that day - deep in my luteal phase - my cortisol was already high, and my stress threshold was low. Cold plunging, while generally beneficial, was pushing my nervous system past its limit. What I needed wasn’t more stress - it was restoration.
Cold Exposure Is a Stressor
That’s not a critique. It’s the point.
Cold plunges stimulate a hormonal cascade—norepinephrine and dopamine rise, cortisol spikes, and inflammation temporarily increases. In one study, cold water immersion led to a 250% increase in dopamine, with effects lasting hours after exposure1. Another found that repeated cold exposure activates brown adipose tissue, improving metabolic function and insulin sensitivity2.
It’s powerful - but that power needs context.
Cold, Hormones, and Timing
For women, stress responses shift week to week. Estrogen and progesterone impact everything from thermoregulation to cortisol reactivity.
During the follicular phase (post-period to ovulation), estrogen rises and stress resilience peaks. Cold plunges tend to feel energizing and mood-lifting3.
During the luteal phase (ovulation to menstruation), progesterone dominates, inflammation increases, and the body becomes more stress-sensitive. Cold exposure here can feel jarring, even dysregulating4.
Add in poor sleep, emotional stress or taxing your body with traveling, and the cold can push a taxed system further out of balance.
Meanwhile, men typically show greater cold-induced thermogenesis and rewarm faster due to higher muscle mass and more active brown fat. Studies also show key benefits in male subjects: improved vascular tone, reduced post-exercise inflammation (e.g., IL-6, CRP), and better glucose metabolism with repeated exposure2.
Yet most cold exposure protocols are still built around male physiology—missing the cyclical nuance required for safe, effective use in female bodies.
Cold Smarts: What to Know Before You Plunge
Match the Method to the Moment
Cryotherapy (2–3 min at -130°F): Shorter, less intense, mood-boosting
Cold Plunge (50–59°F immersion): Greater impact on recovery, metabolism, and systemic stress
Know Your Phase
Follicular = green light
Luteal or menstrual = tread lightly, or opt for heat
Check Your Context: Cold works best when your nervous system has capacity for challenge. If you’re under-recovered or overstimulated - skip it.
The Ancient Future of Cold
The most radical thing you can do with cold exposure isn’t to optimize it - it’s to bring back the context it came from.
To treat it like a conversation with your body, not a punishment. To trust that skipping the plunge, when your system says no, is the protocol.
Cold exposure can absolutely be powerful—for clarity, recovery, even closing deals in frozen lakes. But like all rituals repackaged by the wellness industrial complex, it only works if you remember: not everything is meant for every body, every day.
Where to Cold Plunge in NYC: Equinox Hudson Yards and Remedy Place are two of my favorites!
[48h in] FINLAND
KUUSAMO:
Where I ate: Restaurant Tapio (1 Micheline star) if you want something fancy (it is temporarily closed as the owner just became a mom ;))
Where I stayed: Ruka Peak - you can ski straight from hotel and see the Northern lights if you are lucky (I went in March and saw them!)
HELSINKI
Hotel Maria: central with amazing sauna and spa set up
Ravitanola Palace was worth it and the view is stunning - pictured above and food below!
Some References
Šrámek P et al. Effect of head-out water immersion on cardiovascular and endocrine responses to cold exposure in humans. European Journal of Applied Physiology (2000). https://doi.org/10.1007/s004210000307 ↩
van der Lans AAJJ et al. Cold acclimation recruits human brown fat and increases nonshivering thermogenesis. Journal of Clinical Investigation (2013). https://doi.org/10.1172/JCI68993 ↩ ↩2
Sims ST, Heather AK. Myths and Methodologies: Redefining Female Athlete Health and Performance. Frontiers in Physiology (2018). https://doi.org/10.3389/fphys.2018.01834 ↩
Kaciuba-Uściłko H et al. Gender differences in the thermoregulatory and hormonal responses to cold exposure in humans. European Journal of Applied Physiology (2001). https://doi.org/10.1007/s004210100503 ↩
thanks for breaking this down. i live in montana where there are hot springs everywhere — often adjacent to ice cold creeks. so we go between the two. always wondered why cold plunges feel hit or miss for me and this piece cleared it up!
Fascinating! Thank you!