Each day, thousands of videos circulate on networks showing followers of frozen baths or showers with cold water. The promise is attractive: boosting its vitality and strengthening your body. But what about the heart? Dr. Gérald Kierzek, emergency doctor and medical director of True Medical, takes stock of profits and risks.
Cold shower and heart, what is really going on
Dr. Kierzek explains: “The immersion in cold water triggers a brutal reaction of the autonomous nervous system, known as “Combat-Fuite response“. For the heart, it translates into:
- A temporary increase in heart rate and blood pressure: It is the initial shock reaction. The body is preparing for action by stimulating the release of adrenaline and noradrenaline;
- A potential improvement in cardiac variability: In the long term, regular and controlled practice could lead to the cardiovascular system to better manage stress, resulting in better cardiac variability, a marker of heart health and stress resilience;
- Stimulation of blood circulation: The cold causes vasoconstriction (tightening of blood vessels) on the surface to preserve the heat of the vital organs. At the exit of the water, a vasodilation (dilation of the vessels) of compensation occurs. This “pumping” effect can improve global blood circulation;
- A reduction in systemic inflammation: Exposure to cold is known to reduce inflammation markers, a risk factor in many cardiovascular diseases;
- An improvement in recovery after effort: For athletes, it can help reduce muscle pain and inflammation induced by exercise.
With regular and controlled practice, this stimulation could improve cardiac variability, an indicator of good cardiovascular health. It also promotes blood circulation thanks to the alternation vasoconstriction-vasodilation, reducing inflammation and helping recovery after effort.
Cardiovascular risks not to be ignored
If the shock of the cold can strengthen the cardiovascular system, it can also experience it dangerously. “”The main danger lies in the brutal increase in blood pressure and heart rate. This can trigger a hypertensive crisis, cardiac arrhythmia or myocardial infarction“, warns the doctor. But that’s not all:”The cold shower can cause angina, that is to say chest pain due to a lack of oxygenation of the heart, triggered by the sudden effort on the heart“.
Extreme cold stress can cause atheroma plate rupture or a coronary spasm. These complications occur mainly in people with cardiovascular history, or fragile due to other factors.
Who can get started?
Dr. Kierzek insists that some people must absolutely avoid this practice, especially if they have:
- Unexpected high blood pressure;
- Heart failure;
- Coronary disease (angina, infarction, stents);
- History of stroke or AI;
- Known cardiac arrhythmias;
- Uncontrolled risk factors (tobacco, diabetes, cholesterol);
- Raynaud’s disease;
- Feverish state or acute disease;
- Very sedentary lifestyle.
And if you want to adopt it …
For the others, the cold shower can be practiced with caution. “”Start gradually: finish a normal hot shower with 15-30 seconds of cold water, and increase the duration very slowly. Do not target the head and the chest directly, start with the feet and legs. Listen to your body: if you feel discomfort, significant shortness of breath, dizziness or chest pain, stop immediately“.
Finally, in case of doubt, the doctor recommends consulting, especially after 40 years or in the event of family history. “”A simple effort test can assess the ability of your heart to manage stress“.