The Good: Isn’t Really Good
Most people start drinking caffeine because it makes them feel more alert and improves their mood. Many studies suggest that caffeine actually improves cognitive task performance (memory, attention span, etc.) in the short-term. Unfortunately, these studies fail to consider the participants’ caffeine habits. New research from Johns Hopkins Medical School shows that performance increases due to caffeine intake are the result of caffeine drinkers experiencing a short-term reversal of caffeine withdrawal. By controlling for caffeine use in study participants, John Hopkins researchers found that caffeine-related performance improvement is nonexistent without caffeine withdrawal. In essence, coming off caffeine reduces your cognitive performance and has a negative impact on your mood. The only way to get back to normal is to drink caffeine, and when you do drink it, you feel like it’s taking you to new heights. In reality, the caffeine is just taking your performance back to normal for a short period.
The Bad: Adrenaline
Drinking caffeine triggers the release of adrenaline. Adrenaline is the source of the “fight or flight” response, a survival mechanism that forces you to stand up and fight or run for the hills when faced with a threat. The fight-or-flight mechanism sidesteps rational thinking in favor of a faster response. This is great when a bear is chasing you, but not so great when you’re responding to a curt email. When caffeine puts your brain and body into this hyper-aroused state, your emotions overrun your behavior.
Irritability and anxiety are the most commonly seen emotional effects of caffeine, but caffeine enables all of your emotions to take charge.
The negative effects of a caffeine-generated adrenaline surge are not just behavioral. Researchers at Carnegie Mellon University found that large doses of caffeine raise blood pressure, stimulate the heart, and produce rapid shallow breathing, which deprives the brain of the oxygen needed to keep your thinking calm and rational.
The Ugly: Sleep
When you sleep, your brain literally recharges, shuffling through the day’s memories and storing or discarding them (which causes dreams), so that you wake up alert and clear-headed. Your self-control, focus, memory, and information processing speed are all reduced when you don’t get enough—or the right kind—of sleep. Your brain is very fickle when it comes to sleep. For you to wake up feeling rested, your brain needs to move through an elaborate series of cycles. You can help this process along and improve the quality of your sleep by reducing your caffeine intake.
Here’s why you’ll want to: caffeine has a six-hour half-life, which means it takes a full twenty-four hours to work its way out of your system. Have a cup of joe at eight a.m., and you’ll still have 25% of the caffeine in your body at eight p.m. Anything you drink after noon will still be at 50% strength at bedtime. Any caffeine in your bloodstream—with the negative effects increasing with the dose—makes it harder to fall asleep.