I've been doing the cold shower challenge for a week now but I'm not sure if I'm doing it long enough. Currently I'm at about 30 seconds - does anyone have research on the optimal duration for health benefits?

I've read some articles recommending anywhere from 30 seconds to 5 minutes, but it seems like there's a lot of conflicting information out there. What does Brett recommend specifically?

Also, does anyone have tips for making it easier? I still find myself dreading it every morning!