Remembering to breathe while you work out may seem like a no-brainer, but it's easy to forget when you're focused on the exercise. Do it too often and you may feel the room spinning, says Alan Beyer, M.D., executive medical director of Hoag Orthopedic Institute in Irvine, Calif. "Some people have a habit of holding their breath, which could cause dizziness,” says Dr. Beyer. "The best way to avoid holding your breath is to focus on inhaling and then exhaling before you exert effort. This way you've maximally brought oxygen into your lungs and bloodstream. It's the first thing you learn in Pilates. Take a deep breath and then do the move after you exhale."
Low blood sugar and dehydration may also cause dizziness, he adds. You need to load your body with water and nutrients before you staring working out , says Beyer. If dizziness persists, see a doctor to rule out something else (e.g. an inner ear problem).