The biggest mistake people make starting contrast therapy is going too hard too fast — maxing out sauna time and plunge cold on day one, then quitting a week later because it's miserable.
A better starting point: 10 minutes of sauna at a moderate temperature, followed by 30-45 seconds of cold plunge at a temperature you can tolerate without gasping uncontrollably, for 2-3 rounds. Build duration and intensity over 4-6 weeks rather than starting at your target protocol.
Our Contrast Lab protocol builder defaults to a similar conservative starting point for exactly this reason.