SCOTTSDALE, Ariz. — Mark Melancon sprints to the mound and his heart starts racing — at precisely 183 beats per minute.

It’s all by careful design for San Francisco’s new closer.

“I didn’t realize it was that high,” Giants manager Bruce Bochy said Tuesday. “Adrenalin kicking in. It’s a beautiful thing. Adrenalin’s a beautiful drug as long as you can control it.”

Melancon sure can, and he is monitoring his every movement. The right-hander is wearing a heart rate monitor under his uniform.