Bathwater can directly affect blood pressure and heart rate. When the body is exposed to hot water, blood vessels under the skin dilate, causing a temporary drop in blood pressure.
However, at the same time, the heart has to pump blood harder to maintain circulation, causing the heart rate to increase and the burden on the heart to be greater. Conversely, cold water causes vasoconstriction, leading to a sudden increase in blood pressure, according to the health website Verywell Health (USA).
People with high blood pressure or cardiovascular disease should avoid taking excessively hot baths as this can cause a sudden drop in blood pressure. PHOTO: AI
Both vasodilation caused by hot water and vasoconstriction caused by cold water create significant physiological changes that people with cardiovascular disease need to be particularly aware of when bathing. Clinical studies show that the effects of hot water are not entirely good or bad, but depend on the temperature and duration of immersion.
Regarding safety limits, healthy individuals should avoid bathing in excessively hot water, especially exceeding 42-43°C. This helps prevent the risk of burns and excessive cardiovascular reactions.
For people with high blood pressure or cardiovascular disease, the ideal water temperature is around 36-38°C. If you want to use warmer water, around 38-40°C, you should shorten the bathing time and pay attention to any bodily sensations such as dizziness, palpitations, or unusual fatigue.
The duration of soaking is just as important as the temperature. The Cleveland Clinic, a non-profit medical center in the US, recommends that people with cardiovascular disease limit their hot tub soak to 10-15 minutes, or even shorter if they feel tired or dizzy.
Soaking in water for too long can cause a drop in blood pressure upon standing up, leading to dizziness or fainting due to blood pooling in the lower body. This is especially likely to occur in the elderly and those taking blood pressure medication or diuretics.
Additionally, sudden changes in posture after a hot bath, such as standing up too quickly, can cause a rapid drop in blood pressure, increasing the risk of falls or heart rhythm disturbances.
To ensure safety, before stepping into the tub, test the water with your hand or use a thermometer to ensure the temperature is comfortable and doesn't cause burns. Enter the tub slowly, avoiding a sudden rush of hot water over your entire body.
After showering, sit for a while before standing up to allow your body to adjust and avoid dizziness. Drinking enough water before and after showering also helps prevent dehydration, which can cause more significant fluctuations in blood pressure.
Those who need to be especially cautious include patients with congestive heart failure, severe coronary artery disease, arrhythmias, poorly controlled hypertension, or who have recently experienced a cardiovascular event, according to Verywell Health.