Spitting can look disgusting, especially if it’s done in public places. However, when you’re exercising, it could help you breathe more easily.
Normally, we breathe through our nose — this warms up the air and makes it more humid, allowing the body to absorb oxygen more efficiently. But when we exercise, we tend to breathe through our mouth and this causes it to produce more saliva that interferes with our breathing patterns. Hence, it’s perfectly normal to get rid of the excessive mucus produced after running by spitting it out.