Caffeine has a half-life?
Wow. According to How Stuff Works caffeine isn’t out of your system in 4 hours, as I’ve always heard. Instead, it has a half-life of 6 hours, meaning that if you ingest 200mg of caffeine at 9:00 AM, by 9:00 PM when you’re trying to wind down, you actually still have 50mg of caffeine left in your system from that morning java.
So now, if you look forward to 9:00 AM of the next day, you actually still have 12.5mg of caffeine in your system from the previous day. Then you have your typical 200mg more of caffeine, and by the time you’re winding down at 9:00 PM again, you’ve got 53mg of caffeine left in your system instead of just 50. Obviously this cycle gets worse as time goes on.
No wonder coming off of caffeine is so difficult and uncomfortable. But maybe it’s even more worth it than I previously thought.
Note that I’ve determined I’m a “slow caffeine metabolizer“, compared to some people I know. *Cough* Francesca… *Cough*
September 19th, 2006 at
Interesting. I’m definitely a fast caffeine metabolizer. I’m guessing it only has a half life of about 30 minutes in me. Do I have Fran beat? 30 minutes post-fix I often feel the urge to sleep, and have never connected caffeine to sleeplessness. The engineer in me also wants to speculate that the cycle would reach steady state after a day or two of consistent caffeine fixes, but I’m too lazy to prove it. I’m also guessing that as time goes on there is a departure from the half-life decay curve. I think a lot of my wife’s headaches can be connected to inadvertent caffeine withdrawl. Anyway good post…
September 19th, 2006 at
It sounds like you and Fran are about the same… but it still seems like crazy talk to me to hear anyone talk about sleeping 30 minutes after drinking coffee!!!
September 20th, 2006 at
I was for a while drinking a large cup of coffee (4-500ml) everyday after work then sleeping on the bus ride home.
I’ve decided though I’m going to start dirnking mroe tea again.
September 21st, 2006 at
I can sleep 10 minutes after drinking coffee, but not for an extended period of time (maybe 30 minutes or so). Don’t be mad, but glad to hear that you are going to start ‘dirnking mroe tea’ Steve…hehe
September 21st, 2006 at
I’m with Rob on that one. Once went to my local Starbucks at 10 pm… one of those NEED MOCHA NOW moments. Was in bed by 11. I don’t get how caffeine keeps people up. I’ve powered through 4 red bulls in 2 hours (I know… dumb) and gone to bed normally. I think my bloodstream is so saturated with caffeine that it has zero net effect on me. However, go a day without and I experience splitting headaches. Tea is for girls.
November 30th, 2006 at
For those who wish to know if they are “fast” or “slow” metabolizers, out company just introduced CaffeineGEN(TM) Test. See http://www.consumergenetics.com.