How long you cold plunge for matters. There are many ways to access cold water therapy from having a cold shower, to submerging your body in a dedicated cold plunge pool. Either way, setting limits on how long you remain in the cold water is key to reaping the benefits. But cold water is a stressor and comes with risk, so it’s important to know how long to cold plunge for and whether it’s right for you. I spent months testing cold plunge pools and have managed to build up tolerance over time.