Does using O2 tend to make your cycles longer? And what about rebounds? in General Board Posted March 26 · Report reply jh, I feel like a very small number of people have complained about a rebound effect from O2. It is definitely not a common thing. Many people find that if they stay on the O2 for 5-10 minutes after an attack has been aborted, it seems to prevent subsequent attacks. It's kind of annoying to do that when you just want to go back to sleep, but it does help many people. I don't think that anyone believes that using O2 extends cycles, but again, there might be a few people who think that.