Running and hiking with an ostomy?

Hello! I've had UC for 14 years and am now researching surgery. My goal would be to eventually have a j-pouch. I used to be a marathoner and even ran a few ultramarathons several years back, and would like to get back to distance running if my health ever stabilizes. I also love to do long hikes and backpacking. Can someone please tell me if these activities are possible or easy with an ostomy (or with the j-pouch)? My understanding is dehydration could be an issue and I would need to pay extra attention to that. Thanks!