When you're a regular runner, there comes a time that you have to spit to get rid of all the excess saliva in your mouth. There's a certain etiquette to follow when you have to do this, and it starts with making sure there's no one around you that you could inadvertently spit on (and take the wind into consideration!)
But why does all that saliva build up to begin with? It could have to do with dehydration, allergies or other reasons. If spitting while running it irritating to you, you might be able to stop the saliva from building up, depending on the cause.
When running outside in cooler temperatures, your nose must warm and humidify the air you breathe before it reaches your lungs. This action produces mucus in your nose and throat, and the mucus acts as a humidifier to condition the air before it reaches your lungs. The buildup of saliva and mucus will cause you to spit more often.
Of course, running in hot and humid weather doesn't help much either. The hotter temperatures could cause you to sweat more and lose more water than if you were running indoors on a treadmill. Your body might also be reacting to pollutants in the air, which can cause you to produce more saliva.
Exertion and Dehydration
The production of saliva increases when runners begin working their lungs and cardiovascular system. As the body warms up, it will produce more saliva. This affects people differently and might affect newer runners more than exceptionally fit joggers. Joggers who smoke or who have recently quit smoking will produce more mucous as their lungs work to clean themselves during exertion.
Thick saliva, which you might be more prone to spit out, is a sign of minor dehydration. To alleviate the condition, carry a bottle of water or a sports drink and take frequent sips to prevent dehydration. Swish around small amounts of the drink in your mouth every 10 minutes or so, but do not take large gulps. If you hate running with a water bottle, work on drinking enough water before you head out on a run to prevent the build-up.
When outdoors, runners with even mild allergies might notice they are producing more saliva or mucus. Seasonal allergies can cause runners to wheeze and suffer from runny noses and watery eyes. When pollen counts are high, joggers will notice increased mucus production and might experience difficulty breathing during their workouts. Placing the respiratory system under stress from jogging exacerbates allergies and creates the need to spit as post-nasal drip enters the back of the throat.
Plan your workouts for when pollen counts are lower during the day. Windy days also can intensify allergic reactions, leading to an increased desire to spit while jogging.
Some medications can cause increased saliva production, which might become exacerbated when jogging. If you are on a medication that is causing you to generate excess saliva, you might find that physical exertion will accelerate the side effect, causing you to have to spit more when you are jogging. Check with your doctor if you have such a reaction while taking a medication and ask for suggestions to reduce the side effect of excessive saliva or mucus production.