Physiological effects of occasional high caffeine use? (green tea)

I realized that since coming to Japan, I will occasionally drink tea. A lot of it. They sell green tea in 2L bottles here, and I’ve been known to go through one of those or more in a day sometimes. Wiki says that it only has about a third of the caffeine of coffee, and I’m not exactly hugely worried about it, but I wonder exactly what it’s doing to my body. I’ve never really been a big coffee drinker, and while I’ve always liked tea, having to make my own by the cup has heretofore prevented me from drinking it in such large quantities.

It’s not every day that I have one. A lot of times I’ll run out and be too lazy to head to the store to get another one. But I have sometimes rehydrated with tea (if that’s possible-- I mean drink it when I’m really thirsty, or after exercise. Seems to work).

How much caffeine am I drinking? And what exactly does consuming a bunch of caffeine at one time do? I haven’t noticed any symptoms like racing heart or elevated pulse. Usually I don’t have trouble falling asleep afterwards, either.

As an addendum to the other J dopers, did your tea consumption also go up when you came here? If you like the stuff, I don’t really see how it couldn’t. Unless you’re from the UK or something.

Previous thread about health effects of drinking tea. There is also good post about caffeine. Overall it seems safe.

Up to three cups of coffee worth of caffiene (spread out over a day) can be consumed without any worries, *assuming you are otherwise healthy. *That’d make around 9 cups of green tea. After that, please consult your MD- it certainly could be OK, but it’s wise to ask.

I am not a real doctor.