Wednesday, October 13, 2010

Caffeine makes us Crazy - or at least messes with our sleep i *love* good coffee. You? Do you know how you react to coffee? Do you find caffeine keeps you awake/alert? Yes? or maybe you find it doesn't affect your getting to sleep? We know that the magic in coffee is caffeine. Guess what? apparently whether or not we can fall asleep with caffeine is less of an issue than what it does to our sleep quality, in particular, our deep sleep state. That is, it screws it up.

So yes, we might be able to get to sleep (or not) with caffeine in our systems (caffeine genetics is cool), but once we are asleep - based on what's happening in our brain - we just mayn't have enough signaling in the presence of caffeine to tell us to get to DEEP sleep. Wild, eh?

So what's caffeine doing to us? There's a great detailed write up of the  chemistry of caffeine and the brain (calmly titled "Is caffeine a health hazard?") by Ben Best. If i can summarise that article without wrecking it, here's the simplified version, and it's so cool, it just makes sense.

Energy. All or our systems require ATP to do work. Adenosine Triphosphate. Folks into performance are v. familiar with ATP in terms of energy system work, and how Fat for instance is our biggest but slowest generating source of ATP. ATP produces energy by being broken apart into two parts: adenosine  and adenosinediphosphate. The work of energy production is a cycle of putting a and adp together again to from new ATP.

Fatigue. Fatigue is a really interesting process. All we're going to look at here is one tiny tiny bit. When we get fatigued and need rest, the adenosine that gets generated from ATP being broken down, rather than being reassembled into new ATP actually just builds up around the cells and doesn't get used. That's a really good thing. Adenosine on it's one is a brain signaller. As adenosine builds up in this fluid around the cells a bunch of things happen, including effectively signaling the brain to shift down, and when asleep to fasciliate deep, slow wave sleep. As the presence of adenosine goes up, brain wave activity goes down, deep sleep can happen.

Caffeine the Disruptor. An amazing property of caffiene is that it is a Master of Disguise. It connects with adenosine receptors (getting across the blood brain barrier) so that adenosine can't get to those receptors (A1 in particular), and effectively means that the brain doesn't perceive the degree of adenosine build up, and so the signaling to slow the heck down can't happen. All sorts of tests show that with caffeine folks do better in various kinds of tasks, and has been tested with soldiers and athletes rather a lot. But even more recently with soldiers, there's an effort to get away from "stimulants" and think more about scheduling.

Bottom line is that caffeine a way to fake out our system into believing its less tired than it is. There are costs. It's pretty easy to see that while coffee'ing up will give most of us a jolt, we're still actually fatigued, and we are artificially asking our bodies to work beyond what they require for optimal function.

The effects are at least in two ways:

  1. compromised deep sleep quality means our recovery is compromised, and if as athletes we're trying to build physical function, deep sleep is where that building takes place, so we've just screwed the efficacy of our build phase; 
  2. because we're actually still fatigued, and not getting sleep, sleep deprivation effects kick in. Stress goes up, fucntion goes down, ability even to process food, have sex, do anything gets screwed up. Irony eh? we take caffeine to perk up and it ends up actually screwing up our sleep recovery.

The other thing is that caffeine can actually take awhile to flush from our systems. Yesterday in talking about the value of darkness at night for sleep quality, i mentioned zeo as a tool to see how one's sleep quality changes. We use zeo in our lab for "self-monitoring." We can see that deep sleep quality seems to stay effected for days after even with single doses of caffeine. Bummer.

As zeo sleep researcher Stephan Fabregas has said previously at b2d, using caffeine in extremis for the occaision we need it, it can be great and useful. As a regular practice, maybe not so good. Bummer again. But that turns out to be the same for athletes using caffeine to help perk performance too.

The worst part of caffeine apparently is coming off it. Get through that, and sleep gets better, and we need caffeine less. How about that?

Break the cycle (of dependence); improve sleep quality, improve recovery and quality of life.

If you are a big starbucks mega coffee drinker, and you try going from Really Big to Not Quite So Big to maybe one less a day, let me know if you notice a difference over time of being on less or none of the stuff.

Good luck on your caffeine control mission.

Quick Ref
Gore RK, Webb TS, & Hermes ED (2010). Fatigue and stimulant use in military fighter aircrew during combat operations. Aviation, space, and environmental medicine, 81 (8), 719-27 PMID: 20681231

Ferré S (2010). Role of the central ascending neurotransmitter systems in the psychostimulant effects of caffeine. Journal of Alzheimer's disease : JAD, 20 Suppl 1 PMID: 20182056

Yang, A., Palmer, A., & Wit, H. (2010). Genetics of caffeine consumption and responses to caffeine Psychopharmacology, 211 (3), 245-257 DOI: 10.1007/s00213-010-1900-1


Aaron Griffin said...

Out of curiosity, I see conflicting info on when to stop drinking caffeine during the day for proper sleep at night. Do you happen to have any info related to this?

Unknown said...

As always a great post!

I'm also interested in when to stop drinking the caffeine. I'm a drinker of tea (greens & pu-erhs mostly)... maybe half a gallon or so of it daily.

Where is the limit for getting good sleep with regard to amount of caffeine / day and hours before sleep?

dr. m.c. said...

Well folks you're both asking kinda the same question, and from what i've found, the usual rules about caffeine so that one can get to sleep (so say 4 hours before trying to get to sleep) may not rock.

As said, we've seen what seems to be a caffeine effect on deep sleep for days after a single coffee hit. Now whether that's knock on effects from the caffeine and it takes a bit to get back to equilibrium i'm not sure. I'll hope i can get steve to speak about this here.

And marcus, i'm with you: in the UK i don't even drink coffee (that's a US treat) - i drink a LOT of tea.

So here's what i'd suggest: stop drinking it for a few days so that it's really flushed out of your system, and see how you feel.

Again the cool thing about the zeo is that you can actually *see* if the distance away from caffein is improving deep sleep - again - assuming nothing else is changing in your life.

I'll ask steve if he can comment...


Piers said...
This comment has been removed by the author.
Piers said...

Caffeine is meant to have a half life of around 2.5-5 hours. That means if you have a cup of coffee in the morning, 15 hours later you could still have the equivalent of a 1/8 of a cup still in your system... Think about if you have it before bed... that's the whole nights sleep down the toilet.

Mike T Nelson said...

Cool stuff. Thoughts on the studies that show some are "long" vs"short" metabolizers of caffeine?

Once I get my energy drink study done, I will be working with Dr. Lowery on a study to look at the effects of caffeine or perhaps energy drinks on power output this Spring.

rock on
Mike T Nelson PhD(c)
Extreme Human Performance


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