Adrenaline is a huge factor in pitching, but oftentimes in my career it actually worked against me. I've always found my pitches flatten and and hang more when I'm jacked up on adrenaline. I think it's really important to understand WHY you are effective as a pitcher. If you are a true fireballer who gets by on high heat and pure power, the adrenaline boost is probably a useful thing. I was a sinker ball throwing sidearmer that relied on late movement and deception. When I was super fresh or too pumped up for an appearance, I probably got an extra 2-3 mph, but that only got me to 86-88 - nothing that a hitter can't catch up to. I was way more effective making sure I dominated the ball and got my good sink at around 82-84.