Contrast showers are healthy and can be fun if you brace yourself and don’t let yourself be put off by the cold water. The principle is the same as with the traditional Kneipp applications: the cold/warm water shocks constrict and dilate the blood vessels, which indirectly strengthens the immune system, metabolism, circulation, heart and body temperature regulation and our mood. So contrast showers are particularly recommended for people with high blood pressure.
The difference between contrast showers and traditional Kneipp affusions is that the Kneipp affusions are always applied with a jet of water, forming a beneficial film of water on the skin. In a shower, a number of separate jets of water hit the skin (the “watering can effect”).