Chances are its just the feeling of nausea brought on as a result of running hard. The bodies natural reaction is to divert blood from accessory systems and muscles to the ones most in need of oxygen. Lack of blood supply to the digestive system often gives rise to the feeling of nausea which in turn leads to vomitting if there are any stomach contents.
As the digestive system is pretty much in direct confilct with adrenaline and exercise, its probably just down to over exertion. A bit like when 'stitch' is induced.
Posted: 19/12/2011 at 16:02