Hi Marg,
I am probably not the best Topamax user to ask about engaging in intense exercise because I have a confounding health condition. Prior to getting MAV in 2010 I would do up to 2 hours of intense aerobic exercise every day and lift weights. When I got MAV I was so dizzy I could not walk straight and I put considerable strain on my right ankle. This injury triggered a disorder called reflex sympathetic dystrophy that now has involved both legs. It is chronic and severe. I am now only able to slowly walk a couple of blocks at best. I do not get dizzy doing this.
Be aware that when you are on Topamax you may have more difficulty controlling your body temperature when you exercise, leading to overheating. This is something to think about on warmer days. You may feel even more lightheaded on these warm days when you exercise. Remember to drink plenty of water.
The dizziness that I experience is a side effect from one of the medications that I have to take.
Take care - Lisa