"stand too long" is correct and usable in written English
You can use it to describe a situation in which someone has remained in a standing position for an extended period of time. For example, "I had to sit down after I stood too long in line at the grocery store."
"It was: O.K., I can't stand too long like this.
If I stand too long it is really uncomfortable.
By then, his aching knees did not allow him to stand too long at one time, so he covered Westminster's two-day show from a wheelchair.
They cannot stand too long without saying who they are.
Naive doesn't even come close to the President's miscalculation, but that's what happens when you stand too long looking into the reflecting pool.
If they stand too long at room temperature, they risk turning mushy.
They all passed up the cake telling her that it had probably stood too long and got dusty.
Watching the interaction that followed, Mr. Luna noted that Mr. Guingona stood too long at the couch, towering over the women, which probably made them uncomfortable.
"I thought, watching from the bench, that he stood too long on the opponent's leg," van Gaal said, "It was the inner foot, and not a foul with full force.
A woman down to the gritty dregs of a crack binge in "Going Native" faces the same intimations of disintegration that threaten Gwen, "a sense of being peeled away, ushered toward a revelation she wasn't capable of bearing, as when one stands too long before a mirror and the images shift toward the unrecognizable, the ultimate horror of simple things".
In the kitchen, Wilfred stood stooped at the sink, his arthritic hands as gnarled as ginger root, his body not cooperating, leaving him unable to stand for too long.
