I have decided to start going to exercises classes whilst my dd is at nursery to try and get rid of all my saggy bits!!!! I have got the brochure from my local sports centre about what classes they do, and it's confusing me a bit (I'm a bit slow - I know!!) What is 'low-impact' and high-impact' exercise? And what would be the best thing to start with for someone who as done absolutely NO sport since leaving school about 12 years ago!!!!