I recently started working out after several years away from the gym. I've been doing 30mins of cardio on the eliptical trainer, working up to a good sweat with no problem. Well, today I decided to try a step class, something I used to love, and I was only able to make it about half way through when I started to feel dizzy. I figured I would be ok after a few mins so I continued, and then a few mins later I started to feel nautious so I left the class.

My question is what causes this to happen and what can I do to overcome this so I can finish a 60min step class without feeling like I'm going to pass out. More info: It was a 'beginner' step class and I intentionally was not pushing it too hard since it's my first one in a long time.

Sounds like you ran out of fuel for exercise, aka your blood sugar crashed, aka you bonked big time.

Eat a moderate to large carbohydrate feeding 30-90 before your exercise session, and NO CAFFEINE if you don't want to bonk again.

I like sweet potato/yam or oats before workouts.

Sweet potatoes...yummmmmy. One of my absolute favorites.