My fully vaxxed B-I-L is one of those intense fitness guys that does marathons, Iron Man and Spartan challenges. He did a 10 hour non-stop event at a local 4,000+ foot mountain this fall.

He's never had a problem in the past 15 years, but this summer he cramped up so bad his family had to drive 3 hours to the mountain to rescue him. He couldn't walk or get into his car even though he hydrated throughout the event.