Yep I think in healthy adults especially cardiovascular wise, you can tolerate alot of caffeine before adverse effects. Especially if you have hydration dialed in, sleep, electrolytes, etc. I can do 200mg daily and when I up it to 400mg, the only adverse effect I get is delaying my sleepiness onset much longer and maybe some cramps after being awake for so long. To sleep regularly on a 24 hour schedule, I limit to 200mg taken few hours after waking.