Re: How long can the body hold a tolerance for caffeine?

As with many other drugs, the human body develops a tolerance to most of 
caffeine's effects – with increased exposure to caffeine, the same dose 
produces a reduced effect, or a larger dose is required to produce the 
same level of effect.  The degree to which tolerance develops can vary 
from one person to another and with the amount of caffeine consumed.

Typically tolerance for a drug gradually abates when exposure to the drug 
is eliminated.  How rapidly this occurs depends on the drug and can vary 
from one person to another.  As far as I am aware from the scientific 
literature, the rate at which tolerance for caffeine decreases with time 
after consumption has stopped has not been thoroughly studied.  One study 
reports that the loss of tolerance for caffeine’s effect on blood pressure 
is rapid (within a few hours) but another reports that tolerance for 
caffeine’s diuretic effect can last for days.

But based on the rates at which tolerance disappears in drugs that have 
been carefully studied, it would be surprising to me if your tolerance for 
caffeine’s effects had not worn off after the two months of abstaining 
from caffeine that you describe.  If you can take 200 mg of caffeine 
without noticeable effects, I suspect that your body naturally has a lower 
response to caffeine than the average person, and this would be true even 
if you hadn’t once been a heavy consumer of caffeine.  Some people are 
simply more sensitive to caffeine than others, and you are probably on the 
naturally less sensitive end of the spectrum.