Sometimes when people stand too long and lock their knees, for some reason the locking knees causing fainting. Happens in weddings too often.
Ha....saw a groom faint at his own wedding once.....
when I was in the service, oh these many years ago, if I had to stand at attention for any extended period of time, my legs and arms would go to sleep..
Once when I was young, I locked my knees during a choir recital, LOL. It wasn't a fun experience considering the fact that I was on the back, top riser.
Hopefully, this is nothing serious.
Talking about fainting reminds me of my niece. She was very, very sick for months. She went and had every test known to see what the problem was. She went to specialists in Memphis and Birmingham. Well, one day, she was talking with my daughter. DD told her to have her vitamin B 12 checked to see if that was causing her to pass out when she walked, lifted her hands to wash her hair, etc. Sure enough, that was what was wrong with her. A simple test did what numerous tests did not do, find the problem. You never know.