What Causes Persistent Dizziness, Cold And Cough?

Hi there I have had several fainting or near fainting spells in my life. Increasing feelings of syncope but able to resolve prior to fainting by consuming sugar, or cooling neck. Happens alot under exertion when using thigh muscle, and yet I can complete a 1 hour boot camp class without fainting and then other boot camps with little cool air I feel I need to pass out. I realize that once I get scared of the feeling I am going to die, than I increase my breathing which if I dont control can make me syncope. Earliest memory of passing out I was 12 biking too quickly to babysit and I fell on the front step asking for sugar. When I am in pain (bang knee etc) I feel I am going to pass out. Now my 7 year old daughter has had two syncope episodes in past 4 mos both in morning, with mild cold cough through night. Both times, I need to eat then passes out. Can you suggest?