There is little scientific evidence to suggest that drinking cold water is bad for people. In fact, drinking colder water may improve exercise performance and be better for rehydration when exercising, especially in hotter environments.
How long should I take a cold shower?
Taking a cold shower for up to 5 minutes, 2 to 3 times per week, was shown to help relieve symptoms of depression in a clinical trial. For people with depression, cold showers can work as a kind of gentle electroshock therapy. The cold water sends many electrical impulses to your brain.
Do cold showers actually do anything?
Impact of cold showers on your immune system and mental health. Researchers have found that taking icy showers may heighten your immune system and make you more resistant to illness. A clinical trial in the Netherlands found that cold showers led to a 29% reduction in people calling off sick from work.