Not as mature and developed work as it could be but I finished a post on the effects of caffeine, which is at least more complete than anything I was able to find online:
The short version: it’s hard to summarize, and of course effects varying by person render generalities less useful (not a point I treated at length, but it’s in there). The general research take is that there is no problem with taking in up to 400 mg. caffeine per day, and a range of symptoms may show up if someone moves into 500-600. Over 1000 things get interesting, paralleling anxiety related mental illness. Someone can be dependent on caffeine at lower levels, essentially addicted if they only take in 100 mg per day (one cup of coffee range, 2 or 3 cups of tea), so it seems possible that other effects of that dependency are subtle and aren’t being caught.
An interesting question is why all this happens, why caffeine has the effects it does. What these studies are talking about is immediate reactions to caffeine, side effects, but a more relevant concern might be the impact on sleep cycle patterns, long-term disruption of REM cycles necessary for normal dream states. This isn’t being studied in the same way, or at least not as much as correlation studies with health risks or benefits like heart disease risk. It wouldn’t be impossible to do so but it would be difficult, although isolating lifestyle inputs would be nearly impossible, without putting a group of people in study conditions isolation for half a year. That post covers a good bit more scope, just a long read since me summarizing medical study findings—there are a few to cite—would change what they actually say to how I interpret that.
Your blog post was quite interesting. I don’t know how much caffeine I have on the average day and it depends if it’s a day off or a work day. On a day off I typically have at least two gongfu sessions with puerh tea and perhaps a cup of black tea. Then I switch over to decaf and caffeine free like peppermint. On a work day I typically have one cup of black tea and commonly one energy shot. I don’t know how many mg of caffeine is in the gongfu session but I imagine I like you are averaging around 400mg of caffeine per day. Ironically, on a work day I probably have less caffeine even though I typically have an energy shot before work.
Thank you for the work you put into your article, John. It’s helping me figure out how to get more restful sleep. Sometimes I have trouble falling asleep, but more often I can fall asleep, but I either don’t sleep deeply or otherwise do not feel refreshed when I wake.
I’ve already cut back how late in the day I drink caffeine, but didn’t realize how long the half life is. More tinkering to do.
It is really impossible to know how much caffeine is in a cup of tea or in a gongfu session. Presumably there is more caffeine in a gongfu session when I am using 8g or 10g of tea in a 150ml vessel over twelve steeps. But there are too many unknown variables too know how much caffeine is in your tea. One of the few good things of Teavana Tea is they test for caffeine and tell you the approximate caffeine in a cup. I only wish the rest of the industry would follow suit.
I have an anxiety disorder too, and used to organise my teas based on caffeine content, i.e. high in one draw, to be drank only once per day, medium-low in another, to be drank once or twice, and uncaffeinated in another, which I drank most. It took a while, but eventually and over time my tolerance built itself up naturally and I slowly introduced more high caffeine teas into my daily habits. I know saying ‘wait it out’ isn’t exactly what you were looking for, but I thought I would share my own experience anyway. Good luck!
My problem with caffeine isn’t anxiety but insomnia. If I have caffeine late in the day it will keep me up. I drink a lot of peppermint tea in the evenings.
When I worked/studied normal hours I had a caffeine cut-off point each day, but now I work nights so I take as much as I can get lol.
My problem with insomnia is thyroid and anxiety. Caffeine just complicates things. If I need to stay awake in the evening and I need a boost, I go for coffee since it has a shorter arc. It takes up to twelve hours (usually less. learned in my tea sommelier class, for what that is worth!) for tea caffeine to leave the system so coffee is much easier on my sleep cycle in sporadic doses. I’d much rather tea of course.
A more intense high but not as long winded really works in the evenings, but! I need to be legitimately tired to the point of really wanting a nap… or else it will keep me up longer than I want.
I didn’t dwell on it in that post but the half-life idea of caffeine being removed from your body didn’t make sense to me, for two different reasons. If someone drank twice as much or half as much caffeine it would seem your body (liver, most likely) would process greater quantities slower, not at exactly the same rate. Also unless I’m reading it wrong the caffeine would never truly leave your system, since only half would be removed every six hours, setting up an infinite series, as in Zeno’s paradox.
That wasn’t the main point anyway, pinning down how fast your body would clear caffeine back out. I never seemed to have a lot of trouble with caffeine, since I’d thought my kids waking me was more of a problem, but I’ve cut back in the last week and I do feel fresher, and dream more.
I wrote more about this subject, in part related to running across an interesting reference measuring caffeine levels in lots of types of teas:
The part I didn’t expect is that caffeine levels were all over the place related to measuring different green and black tea levels in teas from different places. I cited another summary work by Nigel Melican that covers some factors that cause that, and that also addressed the idea of how fast caffeine is removed by infusion. Basically it’s roughly as fast as flavor is, so there is no shortcut to decaffeinating your tea (something of an urban legend that people have rejected over and over already).
Unfortunately as it has been noted, the caffeine in tea never that simple. There are so many variables that impact the level of caffeine and on top of this many people note different effects.
We wrote this very simple overview about tea and caffeine: http://www.wanlingteahouse.com/article.php/130/tea-and-caffeine
The other regularly referenced go to guide is (which John has already mentioned in his post too): http://chadao.blogspot.ro/2008/02/caffeine-and-tea-myth-and-reality.html
Interesting, this conflicts with something I had read elsewhere, that small leaves has more caffeine and a large leaf variety like Assamica had less caffeine. I suppose the other source might have meant small leaves from Assamica has more caffeine than large leaves from Assamica but I don’t know and don’t remember exactly where I read it.