Thanks for that @3DStudent. I should add that as soon as the stinging pain occurs I stop immediately and finish with warm water. But yeah, maybe I've gone in the deep end by using the coldest setting, I probably should have eased into it with a cold but not too cold mix. Still, I can't say I've noticed anything negative so far apart from the initial reaction to the cold water, so I'll keep going with it but only what my body can handle without getting 'heroic'.I usually do one every other day. And yeah, if you feel pain then you want to take it easy. In the middle of winter the water is so cold that you will get a stinging sensation if you go too long. The remedy is finding the right amount of hot water to mix in so that you still shiver, but don't get too cold.