One study had people sit in cold water for up to an hour. Their dopamine kept climbing.
Cold water exposure can raise dopamine and norepinephrine and leave you in a calm but alert state. In a study Andrew Huberman describes, dopamine rose by about 250% above baseline in people sitting in cold water up to their necks, and stayed up after they got out.
Huberman opened his Huberman Lab podcast on dopamine with this result because it shows how much behavior alone, with no drugs, can change brain chemistry. Here’s what the study did, 3 effects it points to, and how to approach cold water sensibly.
What did the cold water study actually do?
The study had people sit in water of different temperatures, up to the neck, for up to an hour while researchers measured hormones in their blood. It was published in the European Journal of Applied Physiology as “Human physiological responses to immersion into water of different temperatures” (2000), by P. Šrámek and colleagues.
According to Huberman, there were warm, moderately cool, and very cold conditions. Researchers measured cortisol, norepinephrine, and dopamine. The head stayed above the water.
The numbers below come from Huberman’s description of the study on the podcast, so check the paper if you want exact figures.
What are the 3 ways cold water changes your brain?
Cold water changes your brain by quickly raising norepinephrine and epinephrine, slowly raising dopamine, and leaving you in a calm, alert state. Here’s each one.
1. Norepinephrine and epinephrine rise fast
Cold water quickly increases norepinephrine and epinephrine, also called adrenaline. These chemicals are linked with energy and readiness. If you’ve ever gasped in a cold shower and felt wide awake, that’s this.
2. Dopamine rises slowly and stays up
Dopamine climbs more gradually, starting around 10 to 15 minutes in, and reached about 250% above baseline in the study. After people left the water, the increase was sustained.
This matters because most dopamine boosts are short. A rise that lasts longer may support motivation and a better mood for a longer stretch. Our post on the dopamine baseline crash explains why a steady lift differs from a spike.
3. You land in a calm, alert state
Huberman describes the result as a highly alert but calm state of mind, which he considers a sweet spot for work, social life, and sport. It’s an opinion supported by his experience and the chemistry, not a measured outcome of that study, so treat it as a promising idea.
| Effect | Timing | What it may feel like |
|---|---|---|
| Norepinephrine and epinephrine up | Very quickly | Sharp alertness, rapid breathing |
| Dopamine up (about 250%) | Builds after 10 to 15 minutes | Rising drive and mood |
| Lasting lift after leaving the water | Sustained | Calm focus and energy |
Is cold water safe for everyone?
No, cold water can be risky for people with heart conditions, high blood pressure, or certain other health problems, so check with a doctor first. Sudden cold can stress the heart and cause gasping and panic.
Never go alone into cold open water, and don’t copy a one-hour sit from a lab study. Researchers monitored those participants. Huberman also said he’d cover how to limit the stress hormone cortisol that cold can release, so a short, sensible approach is wiser.
How can you try cold exposure sensibly?
You can try cold exposure sensibly by starting with brief cool showers and building up gradually. Here are 5 steps.
- Get medical clearance if you have any heart or blood pressure concerns.
- Start with the last 30 seconds of your shower. Cool, not painful.
- Breathe slowly. Long exhales calm the gasp reflex.
- Add 10 to 15 seconds each week. Slow progress beats a heroic first try.
- Stop if you feel dizzy or numb. Warm up gradually afterward.
Choosing something hard on purpose can build mental strength too. See whether pain releases dopamine for a related look at effort and reward.
A fair objection is that cold water sounds like suffering with extra steps. The answer is that discomfort is the point only if it leaves you better off. Many people say the 2 minutes after a cool shower are the clearest of their day. If you don’t notice any benefit after a few weeks, drop it and put your effort into sleep or exercise instead.
A simple log helps: after each session, rate your focus and mood from 1 to 5 an hour later, and compare weeks with and without cold.
Does cold water replace other healthy habits?
No, cold exposure works best as one tool alongside sleep, movement, and good food, not as a replacement. The study shows an effect on chemistry, but it doesn’t prove cold water fixes mood, weight, or focus by itself.
Use it as an experiment. Track your energy for 2 weeks and keep it only if it helps you. Pair it with habits that rewire your brain for lasting change.
Frequently asked questions
Does cold water increase dopamine?
In the 2000 study Huberman describes, dopamine rose to about 250% above baseline in people sitting in cold water up to the neck, and the increase was sustained afterward.
How long does cold water take to raise dopamine?
According to Huberman, the dopamine increase kicked in around 10 to 15 minutes after immersion and kept rising.
Does cold water raise adrenaline?
Yes. The study found rapid increases in norepinephrine and epinephrine, which is also called adrenaline, contributing to quick alertness.
Is cold water therapy safe?
It’s not safe for everyone. People with heart conditions or high blood pressure should check with a doctor first, and nobody should copy a long lab immersion at home.
What is the safest way to start?
Begin with the last 30 seconds of a shower at a cool temperature, breathe slowly, and add a few seconds each week.
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