During exercise, there may be a reduction of up to 80% in the blood flow to the abdominal organs, as the body sends more blood to the muscles and skin. This effect may result in nausea, vomiting, stomach pain, and diarrhea.

Can working out too hard make you sick?

But if you do too much of it, exercise can also cause you to be sick more often. Some signs to watch for that may indicate you're working too hard in the gym include an increase in the number of colds you're getting, illnesses lasting longer than usual, and an increase in headaches.

Should I stop working out if I feel nauseous?

So, by following some simple guidelines about training when sick, you can still get in your workout and get rid of the runny nose at the same time. Generally, if you're experiencing symptoms that are “above the neck”, it is ok to take part in mild exercise.