Shower hydrotherapy. Real flu prevention can start in the morning shower. A German study in 1990 used a method that led to 50% decrease in colds and flu of thosQuoted From: https://www.holistichealthpc.com/blog/prevent-the-flu-with-shower-hydrotherapy
"Shower hydrotherapy. Real flu prevention can start in the morning shower. A German study in 1990 used a method that led to 50% decrease in colds and flu of those who participate. What"s even better, when those using this treatment did get a cold or flu their symptoms lasted half the time of those who did not use this method! The treatment is ending a normal hot shower with cold water in the following fashion: Initially the water is only cool and only lasting for a few seconds, gradually decreasing the water temperature and increasing the duration of spray for as long as 2 minutes over several days and weeks. End the shower with a vigorous dry towel rub. This time-tested Naturopathic method works by exercising the blood vessels in the skin and strengthening the muscles that surround the vessels, making them more dynamic and better able to adapt to weather changes and better able to distribute blood so that infections can be addressed earlier and more effectively.
It is a tonifying treatment that is to say it tones and provides strength. Start slowly if you are new; like any exercise, it is a building process."