A question about diabetes

[Stinky The Clown]

Yesterday, in the Indy 500, there was a driver who is a diabetic. They did a story wherein the noted that, during the race, his blood glucose was being constantly monitored. In the event of a problem, a pit crewman had a small supply of epipens with which to inject him with insulin as needed.

Okay, fine. That all makes sense. Here's where they lost me.

They wanted his numbers to be between 280 and 320.

That seems awfully high to me. Most people want to keep their number under 140.

Why would they want him at 300?