Question 284 of 433
What do cold plunges actually do?
The short answer
They wake you up and may briefly lower stress. There is no evidence they extend life, and they carry real risk for people with heart disease.
A 2025 review pooled eleven studies with about 3,200 people. It found a short-lived drop in stress about twelve hours after immersion, slightly better sleep and quality of life in some groups, and one study in which people who took cold showers had 29 percent fewer sick days. Effects on mood and immunity were small or unproven.
Two cautions. Cold water causes a sudden jump in blood pressure and heart rate and can trigger dangerous rhythms; the American Heart Association warns people with heart conditions to be careful. And plunging right after lifting weights blunts muscle growth, so separate the two by several hours.
If you are healthy and enjoy it, start gradually and never alone.
“This book is for education. It is not medical advice, and reading it does not make you my patient or create a doctor-patient relationship.” From the book’s medical disclaimer. Full disclaimer
LIMITED HUMAN TRIALS — Cold immersion: selected short-term recovery or stress outcomes; no demonstrated lifespan extension.Evidence grade (draft mapping)BLimited or small human studiesPart 20, Q284 · Part sources
From Longevity Unmasked by Afshine Ash Emrani, MD, FACC. Medical disclaimer. This book is for education. It is not medical advice, and reading it does not make you my patient or create a doctor-patient relationship. Nothing here is meant to diagnose, treat, cure, or prevent any disease. Medicine is personal: a test, drug, supplement, or exercise plan that helps one person can harm another. Do not start, stop, or change any medication or treatment because of something you read in these pages. Talk with a licensed clinician who knows your history first. If you think you are having a medical emergency, call 911. The author disclaims responsibility for any loss or harm arising from use of the information in this book.