Why is it when you exercise your Saliva gets thicker than when you are at rest? And R

Factual Questions
1

What is the benefit of thicker saliva when you exercise?

Also why do smokers seem to spit a lot? is it because the smokers I’ve seen spitting are just dirty, or is there something wrong with their saliva?

2

2 reasons I can think of:

  1. When you exercise, generally you’re out of breath, or at least breathing heavily. When people breathe heavily, they tend to do it through their mouth. Breathing through your mouth tends to evaporate the water from your saliva, making it thicker.

  2. When you exercise, you generally sweat. If you sweat enough and don’t replace the water, your saliva will generally be thicker, due to less water to make it with.

3

I have not noticed that smokers tend to spit a lot. Obviously if they chew there is a specific reason to be spitting, but not if they smoke.