Exercise-induced nausea is a feeling of sickness or vomiting which can occur shortly after exercise has stopped as well as during exercise itself. It may be a symptom of either over-exertion during exercise, or from too abruptly ending an exercise session. People engaged in high-intensity exercise such as aerobics and bicycling have reported experiencing exercise-induced nausea.
A study of 20 volunteers conducted at Nagoya University in Japan associated a higher degree of exercise-induced nausea after eating.[1]
Lack of hydration during exercise is a well known cause of headache and nausea.[2] Exercising at a heavy rate causes blood flow to be taken away from the stomach, causing nausea.[3]
Another possible cause of exercise induced nausea is overhydration. Drinking too much water before, during, or after extreme exercise (such as a marathon) can cause nausea, diarrhea, confusion, and muscle tremors.[4] Excessive water consumption reduces or dilutes electrolyte levels in the body causing hyponatremia.[4]