If we are not well, then we will bath in hot water. Why is this needed?
Hot water is more good than cold water. Cold water may contains germs. But when we me it hot the germs and impurities get removed from that water.
So it is better to boil water and cool it and have a bath in such water when we are not well.
Some doctors also advice people to have bath in hot water when patients have cold or fever. This shows that hot water is fine for us when we suffer from some disease.