[can16358p]

Do not shock your body or push to extremes. That might be potentially dangerous if you have a cardiovascular condition.

Start light: have your normal shower, then slowly make it colder gradually. Let it push you out of the comfort zone, yet of course stop before it feels hard on your body or heart or anything serious.

You might start with 10 seconds and gradually increase the time until you basically can stand 1 minute under cold water.

About "just cold" or "ice cold" and the faucet: the "coldest" setting changes wildly depending on where you live, but "really cold but not shocking your body" might be a good sweet spot. If you aren't living somewhere particularly cold, the coldest from the shower might not even reach that cold anyway.

Listen to your body and know your limits. Start slow and gradually make it "harder" as your body gets used to it by days and weeks.