[apinstein]

I can't speak for the science, but anecdotally this has been very true for me.

I used to never drink coffee or tea; when I really needed to "wake up" I'd have an espresso and I'd be good for 10-12 hours.

Then I had a kid and found myself needing it daily. After a few months of daily coffee I started to realize that I was exhausted until I drank some coffee; then I wasn't so tired but still couldn't concentrate very well.

Having read a similar article a few weeks ago I switched to tea instead of coffee and I must say I've felt much more productive on tea as well as slightly less exhausted before I drink it.

Would love to hear of others' anecdotal evidence.

[Stormbringer]

I have become very suspicious of caffeine as a stimulant.

For starters, with coffee there is the one-two punch that you get a sugar rush and then later on the caffeine kicks in. (I've read somewhere that caffeine takes about 6 hours to kick in, so if you're perking up straight away it is perhaps not the caffeine per se)

If you don't take sugar and it is the caffeine kicking in, it may be doing so in a particularly horrible and insidious way, that it is (mildly) addictive, and the perking up is simply the absence of the withdrawal symptoms (that old story about banging your head on a brick wall - it feels so good when you stop).

Anecdotally, something I found really interesting is that I play much better chess when I'm off caffeine than when I'm on.

Oh sure, on caffeine you feel all perky and smart and as if your brain is running ten times faster (or whatever), but I think what is actually happening is that we just get bored faster. On caffeine I might only think one or two moves ahead and then pick the moves that my intuition tells me. But off caffeine I can actually 'slow down' enough to play noticeably better, I can think an extra couple of moves ahead over and above the "do something now!!!" mode that caffeine puts me in.

If this is right, then caffeine makes me stupider, because I rush in, and can't sit still to do the deep thinking that really high quality thought and software design require.