Answer to this week's riddle

Travis Hale

Again, the riddle:

On average you'll do it more on a hot day than a cold one, but less when you have a fever. In excess it could be a sign of diabetes or stroke. What is it?

The Answer:

Answer: Yawning
Source: http://www.telegraph.co.uk/science/steve-jones/6583820/Yawning-is-part-of-what-makes-us-human.html