Coffee is the most popular stimulant in the U.S., consumed by nearly 75% of Americans. As a long-time coffee drinker, there’s no doubt that it’s my favorite stimulant (even if its effects are unnoticeable due to my crazy high caffeine tolerance). Even though I crave coffee’s taste, with a slight bitterness and light sweetness, based on taste alone, I sometimes reach for coffee simply for a major boost of energy from its caffeine content.
At times, I feel perkier after a cup of coffee, but there are also times I’m struggling to stay awake. This phenomenon has left me questioning,” Why does coffee make me sleepy?” If you’ve felt that random wave of tiredness hit you after consuming caffeine, you might have asked yourself this question, too. The question of how coffee and tiredness are interrelated can get confusing, especially given coffee’s well-known reputation as a drink that keeps you awake. Here are a few reasons you might feel tired after drinking coffee.
Why does coffee make me sleepy?
Regular coffee drinkers may experience the opposite of their desired effect after drinking coffee, leaving them more tired and sluggish than before their last cup. Sleepiness after drinking coffee doesn’t affect everyone; it may only affect you sometimes or not all. People who drink coffee regularly may also notice tiredness after coffee more than those who drink coffee occasionally. Here’s why.
Effects on adenosine receptors
You may feel sleepy after drinking coffee because caffeine blocks adenosine receptors in the brain. Adenosine is an important brain chemical that impacts our sleep-wake cycles. Typically, adenosine levels will increase throughout the day and decrease during sleep, as molecules will bind to receptors in the brain to prepare the body to go to sleep. However, drinking coffee can interfere with this natural process and prevent adenosine from binding to the appropriate brain receptors.
Although you might feel fine immediately after drinking coffee, Adenosine receptors will begin to bind again as the caffeine wears off. Thus, you may feel a wave of tiredness rush in — leaving you ready for a mid-day nap.
Caffeine tolerance
Caffeine tolerance frequently affects regular coffee drinkers as the body adapts to regular caffeine intake. As tolerance develops, the body will require more and more caffeine to feel those “stimulant” effects. The concept of “caffeine tolerance” is so real that some regular coffee drinkers wonder if there is even any caffeine in their cups. Studies have shown that the brain adapts over time to regular caffeine exposure. This means a person who drinks caffeine daily will produce more adenosine receptors, binding more adenosine and reducing the “stimulant” feelings from drinking coffee. I know “caffeine tolerance” all too well, which could be my sign to give matcha a chance instead.
Blood sugar levels
Most of us have felt an actual blood sugar crash at one point or another, especially after consuming a heavy meal (think post-Thanksgiving dinner). However, caffeine may also impact your glucose metabolism and blood sugar levels. In one study, researchers found that consuming 100mg of caffeine hurt glucose metabolism. While consuming coffee might not affect every person’s blood sugar levels, those with metabolic issues or Diabetes may find coffee makes them more tired.
Another component of why coffee may make you tired could be what you’re putting in your coffee. Many coffee drinkers have a heavy hand when adding sugar to their coffee or maybe consuming pre-packaged coffees that contain sugar. Hidden sugars in your coffee can impact blood sugar levels, leaving you feeling more tired after finishing your cup. Switching to sugar-free coffees, such as by adding zero-sugar coffee syrups, can help support healthier blood sugar levels.
The coffee sleep cycle
