International Coffee Day is upon us, and I hope you're celebrating accordingly.
For me, coffee has always served as a quick source of energy that doesn't come paired with a crash. Yes, it makes me jittery sometimes, but it's all part of the fun—right? I've always been curious about people who avoid drinking it altogether, claiming that it makes them uncomfortably wired for hours on end.
The disparity had me wondering how innocuous caffeine actually is in my body. Had my three to four cups a day been jacking up my heart rate and messing with my sleep the whole time and I'd just been too accustomed to it to notice? Would a healthier life be one without my much-beloved caffeinated companion? Earlier this week, I set out to find answers.
I, a bonafide coffee addict, gave up caffeine (albeit for a day) and monitored how my body reacted. Here's how it went down:
The two-day experiment
I set out on my investigation on Monday: First, I would monitor my heart rate, steps, and sleep patterns on a typical, highly caffeinated day to get a baseline for comparison. (I tracked myself with a Fitbit from try-before-you-buy service Lumoid.)
The day began with three cups of coffee before lunch and one more around 4 p.m. to beat the afternoon slump. My resting heart rate at work toggled at 66 beats per minute and my step count for the day came in at around 16,000. Curious if the afternoon coffee would mess with my sleep quality, I went to bed around 11 p.m. and checked the results as soon as I woke up.
My Fitbit delivered some good news: I fell asleep in less than five minutes, woke up only once, and had a "sleep efficiency" of 91 percent, meaning I was deep asleep for 91 percent of my night. These numbers seemed good, but then again, I didn't have anything to compare it to yet.
On Tuesday, I avoided all caffeine (!) and kept track of how my body reacted. It started out easy enough, but by the time noon rolled around I was experiencing full-on withdrawal headaches. By 4 p.m., my eyes were frozen in a half-closed glare, and the words on my computer screen jumbled together into one hazy ball of sleepy misery. I'd sluggishly check my heart rate every hour or so and noticed that, on average, it was two beats slower than the day before.
I headed home too exhausted to exercise, and my step count for the day came in at under 10,000. Not to mention, I'd distracted myself with food for most of the day and fell asleep around 10 p.m. feeling sluggish, defeated, and completely exhausted. The next morning, I woke up to numbers almost identical to the night before's: I'd fallen asleep quickly, slept for around eight hours, and maintained a sleep efficiency of 91 percent.
This mini-experiment proved that my initial fears were unfounded. The energy I gained from coffee didn't come at the expense of my sleep or health, and all caffeine really did was give me the boost I needed to stay active (not to mention remotely pleasant to be around).
But what made my body more efficient at processing caffeine than others?
The caffeine consensus
It turns out, it's a mix of genetics and lifestyle factors. When you drink coffee, it travels through your stomach, into your bloodstream where it circulates through the body until it lands in the liver to be metabolized.
"Exciting research has found that genetics play a role in how we metabolize caffeine, and some genes can even predict if you are more likely to crave caffeine," Dr. Will Cole, a nutritionist and functional medicine expert, told me.
Cardiologist Dr. Joel Kahn mirrored this idea, adding that not everyone is lucky enough to process caffeine quickly.
"Half of coffee drinkers are slow metabolizers, and three to four cups of coffee or more can raise blood pressure and even the risk of a heart attack," he said.
Hormone expert and author Dr. Sara Gottfried can attest: "I have a gene variant that codes for the enzyme CYP1A2 that makes me metabolize caffeine slowly, so a cup of coffee in the morning makes me stressed, jittery, and bitchy," she explained. "People like me have a greater risk of heart disease when we drink coffee, whereas those who metabolize caffeine quickly receive a longevity benefit from coffee. People without my gene variant don't know what all the fuss is about and drink espresso after dinner."
Lifestyle factors like diet and medications also play a role. Alcohol slows down your ability to absorb coffee while certain meats and vegetables like broccoli, cauliflower, and cabbage speeds up your caffeine metabolism. And medications like birth control actually make you metabolize your cup of joe at one-third of the rate you would otherwise.
The more coffee you drink, the better able you are to tolerate its effects, so you can bet I'm ringing in today's holiday with many, many mugs filled to the brim.