Cold water on the face slowed teenagers' hearts by 68 beats a minute
A 2025 Physiological Reports field study recorded the heart rhythms of Swedish ninth-graders during face immersion in 10°C water and body immersion in 2°C water.
The paper
Assessment of arrhythmias and heart rate response in healthy adolescents performing face immersion and body submersion in ice‐cold water
Lundström A, Karlsson M, Rydberg A, Wiklund U. Physiological Reports, 2025;13(13):e70430.
See the study at a glance
- Design
- Observational field study with continuous ECG
- People
- 54 teenagers in the face test, 20 in the body test
- Who they were
- Healthy ninth-graders aged 15–16 in Sweden.
- What they did
- Face immersion in 10°C water during a breath-hold of 25.7 seconds on average, and body immersion in 2°C water for about 42 seconds.
- How long
- One session
These numbers came out of it
−68 bpm
Heart rate fell by 68 beats a minute on average when the teenagers held their breath with their faces in the water.
−7 bpm
Among the 18 who did both tests, heart rate fell 7 beats a minute on average in the first 25 seconds of body immersion.
8 of 54
Eight of 54 teenagers had irregular beats during face immersion. Six had extra beats from the upper chambers, and two had ventricular bigeminy.
4 of 20
Four of 20 teenagers had extra beats from the upper chambers during body immersion.
The researchers did this
Swedish researchers recorded continuous ECGs from healthy 15- and 16-year-olds outside the lab. In one test the teenagers held their breath with their faces in 10°C water for 25.7 seconds on average. In the other they immersed their bodies in 2°C water for about 42 seconds.Source 1 · Cross-sectional studyAssessment of arrhythmias and heart rate response in healthy adolescents performing face immersion and body submersion in ice‐cold waterLundström A, Karlsson M, Rydberg A, et al.. Physiological Reports, 2025.Read the paper ↗PubMed ↗
Cold water on the face set off a strong diving reflex (a built-in reflex that slows the heart). On average, heart rate fell by 68 beats a minute.Source 1 · Cross-sectional studyAssessment of arrhythmias and heart rate response in healthy adolescents performing face immersion and body submersion in ice‐cold waterLundström A, Karlsson M, Rydberg A, et al.. Physiological Reports, 2025.Read the paper ↗PubMed ↗ It peaked near 125 and bottomed out near 58. In the 18 teenagers who did both tests, heart rate fell 59 beats in the first 25 seconds of face immersion against 7 in body immersion.
Six teenagers had extra beats from the upper chambers during face immersion, and in two, early beats from the lower chambers alternated with normal ones (ventricular bigeminy). Four had upper-chamber extra beats during body immersion.Source 1 · Cross-sectional studyAssessment of arrhythmias and heart rate response in healthy adolescents performing face immersion and body submersion in ice‐cold waterLundström A, Karlsson M, Rydberg A, et al.. Physiological Reports, 2025.Read the paper ↗PubMed ↗ The authors judged the risk of a severe heart rhythm problem low for brief body immersion. They thought it could be higher when the face goes under during a breath-hold.
The study can't tell you these things
- The participants were teenagers, and every exposure lasted under a minute.
- The study compared the two tests with each other and had no dry control.
- It recorded one session, so it can't say whether repeated face dips change the heart over time.
- Face immersion came with a breath-hold, so the study can't separate the effect of cold on the face from the effect of holding the breath.
We cited these sources
- 01Lundström A, Karlsson M, Rydberg A, Wiklund U. Assessment of arrhythmias and heart rate response in healthy adolescents performing face immersion and body submersion in ice‐cold water. Physiological Reports. 2025;13(13):e70430. doi:10.14814/phy2.70430 PMID 40624837