my mum has been treated for Bradycardia and has had a pacemaker fitted.. I also experience symthons of Bradycardia i.e dizzyness extreme tiredness flutters and can have a resting HR 35bpm. Im a personal trainer and very active, is high intensity exercise dangerous for this condition
After the implantation of pacemaker, there is no problem, and you mother can carry out all her a activity.  Now coming to your case, extreme training would lead to bradycardia and your resting pulse rate will go low, which is rather a sign of healthy heartHowever 35 is too low, I would suggest you to get a 24 hour holder, which will help us detect pauses, which may be the reason of your dizziness, and during the day do maintain a chart for activities, to see if during exercise your heart rate goes up as expected, other test is Treadmill stress test for phototropic competence, which too would give up an idea of the increase in heart rate with exercise, if it doesn't increase adequately with exercise means that the heart is incapable of the same, and that may cause dizziness. .