After i do heavy exercise i feel like throwing up i have asthma no heart problems past all my tests with flying colors what can it be?

Several: Vomiting is not uncommon among marathon runners and this is considered just a reaction to over-exertion (above what your body can tolerate). However vomiting can also be a sign of exercise-induced anaphylaxis which may or may not related to eating within 3 to 4 hrs prior to the exertion. In anaphylaxis however most people also experience flushing , itching , and/or hives.