extreme dizziness

Dizziness is normally caused by shallow breathing or holding you shoulders too tensed. You can do regular breathing exercises that help this. Breath through the nose counting 5, then breath out through the mouth counting 7. Do this gently and only a few times, but it will help to breath better. Try relaxing the shoulders by scrunching them up and down a few times and make a conscious note of not holding them up by your ears. You'll be surprised how many people hunch there shoulders when they are nervous or anxious. Just one thing, don't do any of this while you are on the bike! :)