ELI5 Exercise Nausea - why do hard workouts make us sick?

Why do we feel like throwing up after intense exercise? What is the significance of the Medulla Oblongata? Why are some people more prone to nausea? What are some practical tips for reducing exercise induced nausea?   ... We explain like i'm five!   Thank you to the r/explainlikeimfive community as always and in particular the following users whose questions and comments formed the basis of this discussion: palcatraz, fogwound, pepeandmrduck, andzjan & askymojo To the ELI5 community that has supported us so far, thanks for all your feedback and comments. Send us an e-mail: [email protected]