i drink coffee. often large amounts of coffee. generally i go for espresso, but sometimes i'll drink hot drip coffee or iced coffee....usually i drink anywhere from 4-6 shots of espresso in a day. today i had a rather large glass of iced coffee with my cereal, and may likely end up getting a double espresso later this afternoon as a pick me up. sometimes i think i drink too much coffee, seeing as i have no less than two shots a day. but then again, i very rarely go so overboard as to get all jittery or to have a "crash" so i guess i'm alright and haven't entered the realm of unhealthy consumption. but perhaps its no good for me. who knows? i'm not giving it up anytime soon!
I'm sure you're aware of the fact that espresso contains roughly 1/2 the caffeine as brewed coffee does. 4-6 shots of espresso translate to 2-3 cups of comparable brewed coffee. As for how much is too much, some studies suggest that around 10-12 cups can fuck you up. Caffeine acts on adenosine receptors which play an important role in heart regulation. A few cups can speed up your heart rate and make you feel energetic, but too much can potentially cause the pace maker cells to go nuts and may result in anything from arrythmias to heart failure. So be careful about how much you drink. I say you shouldn't go beyond 6-7 cups (approx 12 shots of espresso) a day.