A good way to prove it, is by starting a cold, extremely short bath to catch the normal process. Try a simple 30-second rinse at a cooler temperature than normal at the end of your bath. Increase the duration by 30 seconds and lower the temperature slightly after each shower. Once you have reached a few minutes of completely cool water, you will have given yourself a proper Scottish bath and you will be ready to indulge in cold showers, always if you want to. A cold bath will make you a healthier person.