I started exercising again today for the first time since I got that bronchitis 3 weeks ago. I have asthma, and I went to the doctor last week for it and he said to give it a few more days and then if I feel good again to go ahead, so I did. I joined a gym yesterday and went to an aerobics class today. Now, when I got th bronchitis 3 weeks ago, I had just started exercising for the first time in 2 years. I was walking on the treadmill upstairs at my mother's house, and I had been doing it maybe for a week or 2. I started again today, this time with an aerobics class, which is what I used to do in HS and college. I really enjoyed the class, but I felt extremely lightheaded and weird, almost dizzy and a little nauseous, immediately after class ended. Granted, I did take it kind of rough today...I did a step class, and although they tell us to take it at our own pace and many people take it low, no, I had to be the best one and follow everything exactly and make like I am the best...a bigAnyway, this made me nervous and I had some anxiety, but that quickly went away when I came home to see my niece was there. Is it normal to be lightheaded after working out when you first begin an exercise program? How long does it last (meaning after about how many times of exercising does it take for it to go away)? And what causes it? And is there any way to prevent it? I need to exercise to help my IBS-C and to stay healthy. This worked and helped me lose 31 pounds a couple of years back, and I have gained some of the weight back which I don't mind, I would be fine staying at my current weight, I just wanna be healthy and feel good.