It's not the induction, it's the contractions. When you are induced your body is sent into an artificial labour you could call it. The induction drugs are forcing your uterus to contract at a pace much faster and harder than they would normally occur - a way to imagine it is if you get a ball and put it in your hand and repeatedly squeeze it hard on and off every 3 minutes - your hand gets tired really quick and that's what is the hardest. Your body can get really tired really quickly. Normally I wouldn't advocate for an induction at all, but this is one of those times where bubs is better out than left in and I would always rather that a women attempt a vaginal birth first. There are some excellent articles on the bb main site www.bellybelly.com.au/articles that I recommend you read. It's really nothing to be worried about as women do have inductions all the time, but it really does pay to educate yourself about what you can expect.