EU medfag here. Dehydration is BS. You don't start shaking from dehydration. My very simple explanation is: urge incontinence. Merkel is 65 and fat, almost certain to have a mild hypertension. This is routinely treated with beta blocker. Under this therapy urge incontinence is very common. Standing there with a tremendous pressure to pee, knowing the world is watching you wet yourself is very embarrasing. When you can walk, the pressure relieves quite a bit. But you can't do that when the anthem is being played. Your body starts shaking as a reflex, a substitute for walking. As soon as you start walking around, the pressure diminishes, and by the time you get to the rest room, you notice you really didn't have to pee that urgently. That's beta blocker. Completely harmless, but sometimes embarrassing.