Has a cup of coffee ever made you feel “more like yourself?” If you miss your morning cup do you morph into a ravenous troll capable of laying waste to countless villages standing between you and the coffee maker? Let’s unmask the secret sorcery of caffeine.
Oh yeah, I know how big this topic is and frankly I’m sick of hiding from it. What is caffeine and how does it work? BAM!! I just went there, and once a question has been asked there is no taking it back. So let’s play a little academic operation and see what’s just beneath the surface. I’m ready to put the tiny scalpels to this curious query and I don’t care if I get shocked touching the sides! (This is only my 3rd cup of coffee in two hours)
Neurons, Adenosine, and Cantankerous Caffeine Seat Stealers…
Meet adenosine, a mild mannered neurotransmitter (transmits chemical signals from one neuron cell to another) that is very good at inhibiting central nervous system activity. When adenosine is let loose in the blood stream to dock with receptors it likes to slow things way . . . way . . . doooowwwn. Levels of Adenosine build up with each hour we are awake, gradually “suppressing arousal” as the cool kids (scientists) eloquently put it. This is of course a vital evolutionary adaption since this action eventually leads to sleep – maybe you’ve heard of it – which we all need to do on a daily basis so that our big ole, multitasking, glucose powered, mammalian brains don’t blow a fuse or something. Adenosine has its very own specialized neural receptors. When some other molecule with a similar molecular structure, like caffeine, sits in adenosine’s chair then a very different reaction can take place.
That charismatic caffeine is more like a party animal in sheep’s clothing that stimulates neurological activity rather than slowing it down. Caffeine triggers increased neuron firing that the pituitary senses and says “whoa now, do we have a fight or flight situation going on here or what?” You see, some of those receptors activate epineprine and norepinephrine, the chemical Ying and Yang (technical term) of our evolved stress response. That could explain why we sometimes get the nervous jitters if we’ve been hitting the grounds too many times in one morning.
Caffeine’s greatest hits…
- diuretic – causes the body to lose water and you know I don’t mean by sweating
- classified as a central nervous system stimulant – (messes wit yo mind) increases the firing of neurons
- antagonist to adenosine – tosses Adenosine’s jacket on the floor and sits in its chair
- activation of epinephrine and norepinephrine receptors – triggering the mild to “yikes” physiological manifestations of the stress/fight or flight response but in moderate amounts stimulates brain function, increases alertness
- affects the release of dopamine – the neurotransmitter affecting movement control, emotional response, and the capacity to experience pain and pleasure..which could explain why we with caffeine withdrawal tend to get the blues when the pitcher of Joe runs dry.
Allow me to quote the cool kids (French researchers) Nehlig, Daval, & Debry at the always charming Universite de Nancy I in France 1992:
“Because caffeine is both water-soluble and lipid-soluble, it readily crosses the blood–brain barrier that separates the bloodstream from the interior of the brain. Once in the brain, the principal mode of action is as a nonselective antagonist of adenosine receptors” Yeah, I think we about covered that.
Ah yes, we can’t forget the Liver…
The liver has a fun enzyme called cytochrome P450 oxidase that metabolizes caffeine into a number of chemical byproducts. One of these chemicals, theobromine, contained in chocolate causes blood vessel dilation and increases urine flow which is why it has been used to treat high blood pressure.
A lot of Docs suggest no more than 200mg per day, or if you have your metric conversion tables out that’s two 5ounce cups of coffee a day, but it varies with sex, body size, and your personal sensitivity to caffeine. So if you’re small, sexy, and sensitive let’s stick to two cups for me ok. Hey, I care.
Yup, it’s still a drug so…
Caffeine withdrawal symptoms can include: severe headaches, muscle aches, temporary feelings of depression, and irritability. Know when it’s time to cut back and give tea a chance.
As always stay classy my friends and never stop learning.