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An hour in 14°C water raised young men's plasma dopamine by 250%

The 2000 European Journal of Applied Physiology study behind the cold-plunge dopamine claim kept young Czech men in water up to the neck for an hour at a time.

The paper

Human physiological responses to immersion into water of different temperatures

Šrámek P, Šimečková M, Janský L, et al.. European Journal of Applied Physiology, 2000;81(5):436-442.

Read the paper ↗PubMed 10751106 ↗

See the study at a glance

Design
Each man was tested at three water temperatures and in room air
People
10 young men
Who they were
Ten young Czech men with an average age of 22.
What they did
The men sat in water up to the neck for an hour at 32°C, 20°C and 14°C, on separate days a week apart. At 32°C the body neither gains nor loses heat. A control session used room air. The researchers drew blood before the session, at 30 minutes, at the end of the hour and after an hour of recovery.
How long
One hour per immersion

These numbers came out of it

+250%

Plasma dopamine rose 250% after an hour in 14°C water. When the same lab ran that hour in 1996, it found no significant rise.

+530%

Plasma noradrenaline climbed 530% by the end of the hour at 14°C. Adrenaline didn't change.

+350%

Metabolic rate rose 350% at 14°C and 93% in 20°C water.

−34%

Cortisol fell 34% during the hour at 32°C, and no water temperature raised it.

The researchers did this

A lab in Prague wanted to separate what water pressure does to the body from what the cold does. Ten young men sat in water up to the neck for an hour at a time. The researchers compared each immersion with a control session in room air.Source 1 · Clinical trialHuman physiological responses to immersion into water of different temperaturesŠrámek P, Šimečková M, Janský L, et al.. European Journal of Applied Physiology, 2000.Read the paper ↗PubMed ↗

At 32°C the body neither gains nor loses heat, so that session showed what pressure does by itself. Heart rate fell 15% and blood pressure 11–12%.Source 1 · Clinical trialHuman physiological responses to immersion into water of different temperaturesŠrámek P, Šimečková M, Janský L, et al.. European Journal of Applied Physiology, 2000.Read the paper ↗PubMed ↗ The men made 107% more urine and their cortisol dropped 34%, while rectal temperature and metabolic rate held steady.

In colder water the men burned far more energy. Their metabolic rate rose 93% at 20°C. At 14°C it rose 350%, and rectal temperature fell.Source 1 · Clinical trialHuman physiological responses to immersion into water of different temperaturesŠrámek P, Šimečková M, Janský L, et al.. European Journal of Applied Physiology, 2000.Read the paper ↗PubMed ↗ That hour at 14°C also pushed plasma noradrenaline up 530% and plasma dopamine up 250%. Adrenaline stayed put and cortisol tended to fall. Heart rate and blood pressure rose by only 5–8%.

Cortisol didn't rise in the water at any temperature, and the hormone changes didn't track the fall in rectal temperature.Source 1 · Clinical trialHuman physiological responses to immersion into water of different temperaturesŠrámek P, Šimečková M, Janský L, et al.. European Journal of Applied Physiology, 2000.Read the paper ↗PubMed ↗

The study can't tell you these things

  • Only ten men took part.
  • The study measured dopamine in blood plasma, and most plasma dopamine comes from the sympathetic (fight-or-flight) nerves or from the gut. Dopamine and its related hormones in the blood barely get into most brain tissue.Source 2 · Clinical trialNeuronal Source of Plasma DopamineGoldstein DS, Holmes C. Clinical Chemistry, 2008.Read the paper ↗PubMed ↗Source 3 · Clinical trialSources and Physiological Significance of Plasma Dopamine SulfateGoldstein DS, Swoboda KJ, Miles JM, et al.. The Journal of Clinical Endocrinology & Metabolism, 1999.Read the paper ↗PubMed ↗Source 4 · ReviewCatecholamine metabolism revisited: from neurochemistry to integrative physiology and pathophysiologyGoldstein DS, Eisenhofer G. Physiological Reviews, 2026.Read the paper ↗PubMed ↗
  • The Prague lab ran the same hour at 14°C in 1996 and found no significant rise in dopamine.Source 5 · Clinical trialChange in sympathetic activity, cardiovascular functions and plasma hormone concentrations due to cold water immersion in menJanský L, Šrámek P, Šavlíková J, et al.. European Journal of Applied Physiology and Occupational Physiology, 1996.Read the paper ↗PubMed ↗
  • An hour at 14°C with a falling core temperature is a far bigger dose than a plunge of a few minutes.
  • The last blood draw came an hour after the men left the water, so the study can't say how long the rise lasted beyond that.

People quote it like this

This is the paper behind "cold water raises dopamine 250%". That line often travels with noradrenaline's 530% and a suggestion that a short plunge lifts mood or focus. The Huberman Lab newsletter of 1 May 2022 describes an unnamed study in which about an hour up to the neck in water near 60°F produced long-lasting rises in dopamine.Source 6 · PodcastThe Science & Use of Cold Exposure for Health & PerformanceHuberman Lab. Huberman Lab Neural Network newsletter, 2022.Read the page ↗ This study's 14°C works out to about 57°F.

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We cited these sources

  1. 01Šrámek P, Šimečková M, Janský L, et al.. Human physiological responses to immersion into water of different temperatures. European Journal of Applied Physiology. 2000;81(5):436-442. doi:10.1007/s004210050065 PMID 10751106
  2. 02Goldstein DS, Holmes C. Neuronal Source of Plasma Dopamine. Clinical Chemistry. 2008;54(11):1864-1871. doi:10.1373/clinchem.2008.107193 PMID 18801936
  3. 03Goldstein DS, Swoboda KJ, Miles JM, Coppack SW, Aneman A, Holmes C, et al.. Sources and Physiological Significance of Plasma Dopamine Sulfate. The Journal of Clinical Endocrinology & Metabolism. 1999;84(7):2523-2531. doi:10.1210/jcem.84.7.5864 PMID 10404831
  4. 04Goldstein DS, Eisenhofer G. Catecholamine metabolism revisited: from neurochemistry to integrative physiology and pathophysiology. Physiological Reviews. 2026;106(4):2521-2578. doi:10.1152/physrev.00005.2026 PMID 42359916
  5. 05Janský L, Šrámek P, Šavlíková J, Uličný B, Janáková H, Horký K. Change in sympathetic activity, cardiovascular functions and plasma hormone concentrations due to cold water immersion in men. European Journal of Applied Physiology and Occupational Physiology. 1996;74(1–2):148-152. doi:10.1007/BF00376507 PMID 8891513
  6. 06Huberman Lab. The Science & Use of Cold Exposure for Health & Performance. Huberman Lab Neural Network newsletter. 2022. Accessed Sep 24, 2026.