Googled: sitting still + physical effects, immobile, motionless, not moving, side effects, many variations and combinations thereof. The only thing I found remotely useful was about blood clots in the legs from sitting on long airplane trips; most articles on sitting too long assume you're doing it more than once, like at the office, and anyway you can get up to walk around. I also tried to find survival stories, but the only ones I found involving being stuck somewhere had to do with animals, or it seemed the person in question was able to move around where they were stuck.
Question: I have a couple of teenagers who fall into a river gorge and end up stuck on a pretty narrow outcropping for something like 13-15 hours before they're rescued. They aren't going to try to move much to avoid falling further, though they can probably shift around a bit, so it's not total immobilization.
Apart from the injuries from falling, I figured they would have some stiff muscles from not moving, but would there be any other obvious immediate problems they might have coming from being stuck? They're both in fairly good shape before this happens (and have some water with them to avoid dehydration). They're stuck during the afternoon until near midnight, and it's early fall.
Alternately, if anyone knows of better Google search terms for this, I'd really appreciate it.