Cold exposure is a natural stressor, that delivers a net positive effect on your body. As an attempt to keep you warm, your heart rate and respiration increase, which enhances blood flow and oxygen delivery. At the same time, norepinephrine floods your brain, reducing inflammation and pain, and boosting your focus and mood.
The best way to start is to try the 20 day cold shower challenge.
Week 1. turn your shower to cold for the last 15 secs
Week 2. turn your shower to cold for the last 30 secs
Week 3. turn your shower to cold for the last 45 secs
Week 4. turn your shower to cold for the last 60 secs
After that you can build up to an ice bath.