You're right, I wasn't very clear in my original post(s). I was mostly addressing the effect it has on regular users, not a one-time use or anything like that. I do agree that it would increase adrenaline, and initially, this would be a "net positive" effect. But after a few days (I think?), your body would adjust to the caffeine and increased adrenaline, and you'd hit the point where you need the caffeine just to hit the same levels you were at prior to any of this intake. So for a "one-time" use, perhaps coffee would help wake you up and stay focused. But I'd expect most people use coffee a little more frequently, and when that happens, they end up with no net positives in these areas (and in fact, they are worse off if they try to stop due to caffeine withdrawals). I'm basically trying to address the idea people have that they need a cup of coffee every morning to wake up, get energy, etc. Although I'd note that the study I linked to earlier did say that "non caffeine users saw no benefit from taking caffeine." So I suppose it might even be debatable that caffeine would have any positive effects in these areas, even for non-regular users. I'm not sure how they judged that effect though. Perhaps it does provide the usual effects (e.g., speeding up heart-rate), but this didn't really result in any quantifiable increase in alertness or wakefulness. I'm a little less likely to go along with that than my previous point (i.e., regular users of caffeine don't get any real benefit from it), but looks like there is some evidence for it. Definitely some interesting stuff going on with coffee and its effects on the body.
Low-Dose Aspirin May Reduce Colon Cancer Risk http://www.medicinenet.com/script/main/art.asp?articlekey=119799 http://www.cbc.ca/news/health/story/2010/12/07/aspirin-cancer.html
