Patients suffering from cardiac insufficiency (heart failure) or circulatory disorders, very common in people with rheumatism, are in danger of collapsing if they take a full hot bath. This is due to the generalized peripheral vasoldilation produced and the increase in hydrostatic pressure on the thorax.

Both these effects of the full hot baths decrease the flow of blood towards the heart and the amount of air in the lungs, which may be counter - productive in the case of people with heart problems.