Skip the Hot Shower After a Cold Plunge? Here’s the Søberg Principle

Wellness Reviewed by a Board-Certified Physician

ID: #2026-063 / Verified: May 19, 2026

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The Principle The Research How to Rewarm Choosing Gear FAQ

At a Glance

• The Søberg Principle says to end with cold and let your body rewarm on its own instead of heading straight for a hot shower.
• In a small Danish study, experienced winter swimmers produced more heat in response to cold than non-swimmers, and spent about 11 minutes a week in cold water.
• Shivering after a plunge is part of how your body makes its own heat, so there's no rush to stop it.
• If you lift for muscle growth, research suggests keeping cold plunges away from the hours right after strength training.

(Image: AI-generated)

You climb out of the cold plunge, teeth chattering, and the hot shower is calling your name. It’s tempting to answer it right away.

There’s a case for waiting. It’s called the Søberg Principle, and it comes down to three words. End with cold.

What the Søberg Principle Says

The idea comes from cold-exposure researcher Dr. Susanna Søberg, and Andrew Huberman's widely shared cold exposure protocol sums it up simply. To get more of the metabolic effect from cold, let your body reheat itself instead of reaching for a hot shower. The same protocol suggests letting yourself shiver, since shivering releases a compound from muscle called succinate that helps switch on brown fat, a type of fat that burns energy to make heat.[1]

In other words, those chilly minutes after you step out are where your body does its own heating.

What the Research Shows

🔍 The Research, Explained: Søberg's team compared young, healthy men who winter-swim two to three times a week with a matched group who don't. Under controlled cooling in the lab, the swimmers ramped up their heat production more than the non-swimmers did. Their habit was modest, too. In total, they spent about 11 minutes a week in cold water, and most paired their dips with sauna sessions.[2]

It’s a small study, about eight men in each group, and it looked at people who already swim rather than assigning anyone to start. The authors are upfront that it can't prove winter swimming caused the difference, since people who handle cold well may be the ones drawn to it. Still, it's where the popular 11-minutes-a-week target comes from.[2]

Cold changes your chemistry too. In a study of young men immersed up to the neck for an hour, water at 14°C (about 57°F) raised blood dopamine by 250% and noradrenaline by 530%. That's a long soak compared with a typical plunge, so treat it as proof the effect is real rather than a measure of what a two-minute dip delivers.[3]

Related Read Why a Splash of Cold Water Calms You Down So Fast →

Cold on the face triggers a reflex that slows the heart through the vagus nerve. Here's how that works, plus a few other quick ways to settle your nervous system.

How to Rewarm Naturally

(Image: AI-generated)

Give it 10 to 15 minutes before you reach for heat. Here’s how to spend them.

1

Step Out: Skip the Towel Wrap

Let the air hit your skin for a minute or two instead of bundling up. Huberman's protocol goes a step further and suggests skipping the towel entirely so your body has to do the drying and the warming.[1]

2

Stay Open: Let the Shiver Happen

Resist the urge to huddle or cross your arms. If you start shivering, that's your muscles making heat, which is exactly what this step is for.[1]

3

Warm Up: Go Lukewarm, Not Hot

Once the shivering settles and you feel steady, a lukewarm shower is an easy way back into your day.

You Might Want to Know When a Warm Shower Is Exactly What Your Body Needs →

Saving the hot shower for later? A warm one about 90 minutes before bed helps your core temperature drop for sleep. Here's how to time it.

If You’re Choosing a Plunge Setup

A bathtub and a few bags of ice will do the job. Dedicated plunge units mostly solve the hassles that come with doing it often. If you’re comparing options, these are the features that make a practical difference.

• Steady Temperature

Ice melts and tub water warms while you sit in it, so a session that starts at your target can drift. A unit with a built-in chiller holds the water at a set point, which makes it easier to repeat the same session week after week.

• Water Movement

Sitting still in cold water lets a thin layer of warmer water form around your body, which makes the cold feel milder. Moving your limbs breaks that layer up, and some units circulate the water to do the same job.[1]

• Clean Water

A plunge you use most days needs water you trust. Many units include filtration and sanitizing systems, so you aren’t draining and refilling after every few sessions.

⚠️ A Few Precautions: Cold water is a real stressor on the body. In the immersion study above, 14°C water raised heart rate and blood pressure even in healthy young men.[3] If you have a heart condition, high blood pressure, or circulation problems, talk to a doctor before you start. Skip alcohol beforehand, avoid plunging alone, and get out if you feel numb, dizzy, or confused.

Frequently Asked Questions

• Q1. Is a regular bathtub enough?

  Yes. Cold is cold, and a tub with ice can get you there. The main differences with a dedicated unit are temperature control, convenience, and how easy it is to keep the habit going.

• Q2. How cold should the water be?

  Huberman’s protocol suggests water that feels uncomfortably cold but that you can safely stay in for a few minutes, spread over two to four short sessions a week. The colder the water, the shorter each session needs to be.[1]

• Q3. Should I plunge right after lifting?

  If muscle growth is the goal, space them out. In a 12-week study, men who did 10 minutes of cold water immersion after each strength session gained less muscle and strength than men who did an active cool-down instead.[4] Huberman suggests waiting six to eight hours after training, or plunging before you lift.[1]

Ten Minutes Before the Shower

Next time you climb out, leave the hot shower alone for ten minutes. Shivering is fine. Your body knows how to warm itself back up, and giving it the chance costs you nothing. Just keep the plunge away from your lifting sessions if you’re training for size.

Sources & References

• [1] Huberman Lab (2022). "The Science & Use of Cold Exposure for Health & Performance." Huberman Lab Newsletter.
• [2] Søberg, S., et al. (2021). "Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men." Cell Reports Medicine.
• [3] Šrámek, P., et al. (2000). "Human physiological responses to immersion into water of different temperatures." European Journal of Applied Physiology.
• [4] Roberts, L. A., et al. (2015). "Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training." The Journal of Physiology.

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