Yes – there is a way to help it – reduce the intensity. Nausea & dizziness are definitely red flags, telling you that something’s not right. High intensity interval training is not for everyone. You need to be in very good aerobic condition from the jump to use that method of training – most people aren’t. I know that HIIT training is “all the rage” these days and steady state aerobic exercise has been getting a bad rap. That’s another issue for another time. Don’t get me wrong – HIIT training is very effective – I include it in my own workouts. But as Janet pointed out, you need to build a good aerobic base before you start cranking up the intensity like that. If your client is still experiencing those symptoms with lower intensity (steady state) aerobic exercise, then it’s time they see a physician to see what’s going on. I hope everything works out well Christine.