Safety, contraindications and screening
Is the heat in an ozone sauna a problem if I have a heart condition or high blood pressure?
Do not use an ozone sauna if you have any heart condition, because heat increases the strain on the heart. Our saunas have automatic temperature control, and we recommend first sessions at 30 °C to 37 °C. If you have high or low blood pressure, ask your doctor before you book.
Half of what happens in the sauna is a steam cycle driven by a 1500 W element, so the heat cautions matter as much as the ozone ones.
The load comes from vasodilation — the widening of blood vessels in warm skin so the body can shed heat. Skin blood flow rises sharply, the heart has to work harder to supply it, and blood pressure can drop, especially on standing. In a healthy person that is ordinary physiology; in someone whose heart is already compromised it is a real strain, and it is the reason for the exclusions below.
Our guidance covers several of them:
- Any heart condition is an exclusion; so is a heart attack or stroke in the previous three months.
- Active hyperthyroidism is an exclusion: an overactive thyroid is already a risk and heat should be avoided.
- Active alcoholism is listed because alcohol raises heart rate and so does the sauna.
- First sessions should run at 30 °C to 37 °C depending on comfort, and only people in good health should go above 37 °C. Ozone starts to break down at 40 °C, so more heat does not make a better session. The display shows the temperature of the air, not your core body temperature.
- Hydration. Drink water before and after; our general advice is 1 to 1.5 litres daily. Fluid lost as sweat compounds the blood pressure drop.
- Being too hot is information, not a preference. Weakness, nausea, headache, dizziness or clammy skin are signs of hyperthermia — body temperature going above its normal range because heat gain outpaces heat loss. Say so, and the operator should turn the heat down or end the session. You can also end it yourself. To get out, open the doors and step out. To stop the ozone, switch the sauna off at its wall socket once you’re out.
All models have automatic temperature control. That is a comfort and control feature, not a clearance: the heart-condition exclusion stands. Blood pressure, high or low, is a question for your own doctor rather than for a threshold on a website.