Science Focus - the home of BBC Science Focus Magazine
Why do I produce so much saliva when I go for a run? © Getty Images

Why do I produce so much saliva when I go for a run?

Subscribe to BBC Science Focus Magazine and get 6 issues for just £9.99

Asked by: Iain Todd, Bristol

The various studies that have looked at this actually show conflicting results. It seems that a short jog in cold weather results in more saliva, while a marathon on a warm day actually reduces saliva production. Your body may initially be trying to offset the drying effect of the extra mouth breathing, but over longer periods dehydration sets in and your body reduces saliva production to conserve water.  


All exercise, regardless of the intensity, also makes you secrete more of a protein called MUC5B. This makes your saliva more sticky and viscous, which contributes to that dry mouth feeling you can get after exercising.

Read more:


Subscribe to BBC Science Focus Magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun facts.


luis villazon
Luis VillazonQ&A expert

Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.


Sponsored content