Apparently this is a myth or so several studies suggest. It’s all in the mind it seems - and that’s us parents’ minds - one study told a group of mothers their kids had had a sugary drink and another group that theirs had had a sugarless drink. The drinks were in fact all sugarless, but the mothers who’d been told their kids had had sugar rated them more hyper afterwards.
But it does make you feel sick, give you headaches, rot your teeth … :-)
It also, as itsmonkeyboy says, gives you a short burst of energy because the glucose goes more rapidly into your bloodstream - but this energy rapidly lost because the body produces more insulin to compensate.
(I’m not sure if links are allowed in answers, but if you type 'sugar high a myth' into google you’ll find some reports on the various studies.)