I can’t remember a time when I didn’t consume caffeine, either in the form of soda, tea, or coffee. Since middle school, I had at least one serving every day. By the time I went to South America, I was a one-cup-a-day coffee drinker, but repeated gastrointestinal illnesses during my travels rendered my stomach sensitive, fragile, and apparently, lactose intolerant. I switched to tea instead, particularly Earl Grey. It was easier on my stomach but still packed a strong caffeine punch.
It took a couple years for me to be able to drink coffee again. I resumed my one-cup-a-day habit, usually in the form of a cappuccino, which I’d take with a lactase pill. In Europe, cappuccinos are quite small, so I started getting two a day to make up for the stinginess in portion size compared to my birth country. Then the habit turned to three a day, and some days even four. My afternoons became a build-up to the moment I’d start drinking coffee, like it was the highlight of my day.
The problem was that I gradually desensitized myself from the caffeine—I no longer felt a boost when drinking. Instead, I was drinking just to feel normal and stable. I knew I had become dependent on it, so I decided to quit caffeine cold turkey, just to see what would happen.
For the first two days I had headaches and was irritable and moody. More severely, I was constantly tired. I’d wake up at my normal time around noon, eat breakfast, work for an hour, then feel the urgent need to sleep again. I had to take daily naps to function. My body seemed to be catching up on its sleep debt, which the caffeine masked, and it wasn’t until one full week that I no longer had the urge to nap.
I carefully monitored my body for changes in the subsequent weeks. The biggest was that I was having more vivid dreams. Whereas before my dreams were short scenes, they now become full stories that seemingly lasted for hours. They were the type of dreams where upon waking you have to think for a few seconds to consider if it really was a dream or not. This suggested to me that I was experiencing a deeper sleep.
The second thing I noticed is a more constant energy level throughout the day, except for a dip around 8 hours after waking when I would feel a bit tired for an hour or so. And that’s it. The benefits were quite marginal, but enough to suggest that caffeine was disrupting my sleep cycle and causing me to mis-read signals that my body was trying to send me. This is not surprising when you consider how caffeine works.
In your brain, caffeine blocks the attachment of a molecule that builds in concentration as you get tired. This molecule attaches to a specific receptor to give you the conscious feeling of fatigue. Caffeine, by attaching to the receptor instead, prevents this feeling of fatigue, sending your body into a state of confused overdrive. The molecule doesn’t disappear while caffeine hogs the receptor—it waits around to attach itself once the caffeine breaks down. When it does, you get a massive feeling of fatigue, often referred to as the “crash.” Therefore caffeine doesn’t create energy—it simply makes an advance on your energy stores that your body has to immediately pay back when the caffeine gets excreted in your urine (its half-life is 5 hours).
My difference in sleep quality suggested that caffeine can linger in my system for well over 8 hours, as its long half-life suggests. While it will be in concentrations too low to make you feel alert or energetic, it will be high enough to disturb your sleep.
At the end of my no-caffeine month, I decided I didn’t want to be dependent—physiologically or psychologically—on a substance just to feel normal, and would only consume caffeine infrequently and randomly like alcohol. Instead of being a habit, I make it a treat for far earlier in the day, at least 12 hours before I plan on going to sleep.
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