One thing's for sure: Americans love their coffee. According to the National Coffee Association, we drink an average of 3.1 cups a day and spend a total of 40 billion dollars every year on it. We depend on our caffeine, for that boost in the morning or for an after-lunch second wind.
What you might not know is that the buzz you feel after slamming a latte is not actually the caffeine.
Adenosine, the circadian rhythm hormone that helps usher in sleep, starts as a slow trickle when you wake up in the morning and slowly builds in your system so that by nightfall, you're ready for a little shut-eye. Caffeine is adenosine's doppelgänger, essentially mimicking its shape and grabbing up all the adenosine receptors when it hits your brain.
Once the adenosine supply is cut off, the naturally occurring stimulants dopamine and glutamate act like a couple of kids with mom and dad on vacation, which is to say: it's party time. That surge of energy is just your dopamine and glutamate going wild.
Caffeine hits your adenosine receptors within fifteen minutes of ingestion and remains in the bloodstream for a full 24 hours. It has what's called a six-hour half life, which means a cup of coffee after lunch will still retain half its potency by bedtime. Although it might give you a temporary pick-me-up, enough of it can greatly disrupt your REM cycle sleep, leaving you emotionally spent the next morning. Your solution? Another cup of coffee.
Once your brain catches onto the pattern, it starts producing more and more adenosine receptors to offset the caffeine. This means you have to keep ratcheting up your intake to get the same high. You are now in a mini arms race of escalation, doing battle with your own brain.
It's like any other addictive drug. In "Caffeine: The Silent Killer of Emotional Intelligence", Travis Bradberry explains what happens when people try to quit: "The researchers at Johns Hopkins found that caffeine withdrawal causes headache, fatigue, sleepiness, and difficulty concentrating. Some people report feeling flu-like symptoms, depression, and anxiety after reducing intake by as little as one cup a day."
When it comes to sleep, caffeine is not your pal.
But stop the presses. As Gary L. Wenk writes in Your Brain on Food, coffee itself is an excellent source of phenols, substances that function as both anti-oxidants and anti-carcinogens. He cites preliminary studies that suggest drinking 3 to 5 cups a day (decaf counts) has a positive effect on Parkinson's disease and prostrate disease, diabetes, and certain cancers. Two or three espressos can also get the job done, he notes. Of course, two or three espressos can also keep you up all night, smoking cigarettes and ordering truckloads of ShamWow.
In the end, it looks like coffee might be a much better friend than caffeine alone will ever be, and decaf might actually be your BFF.