Top 6 Reasons Why Drinking Coffee Can Make You Feel Sleepier

If you enjoy sweet coffee with a lot of sugar and cream, you might experience a "sugar crash" – fatigue caused by consuming large amounts of carbohydrates. When your body processes refined sugars, your blood sugar levels begin to drop. As a result, you may feel drained and exhausted.

Coffee is a diuretic, which means it increases urination and causes dehydration. As a result, drinking too much coffee can leave you feeling extremely tired and sleepy. When your body becomes dehydrated, the water levels in your blood decrease, affecting blood pressure and circulation, which in turn impacts the cardiovascular system. Additionally, cells lose essential fluids, affecting their normal functions and leading to sluggishness and fatigue. If you drink another cup of coffee to fight off this tiredness, the cycle repeats, and you'll feel even more drained.

It may sound unpleasant, but if you drink a cup of coffee contaminated with mold, you’re likely to feel instantly tired and drowsy. Studies have shown that most coffee beans are infected with mold, and the toxins they contain can make you feel sleepy and fatigued. Therefore, it's essential to carefully check the quality of your coffee before drinking it to ensure optimal health.

If you're getting enough sleep but still feel sleepy after drinking coffee, the reason could lie in your genetics. Yes, certain genes in your body determine how sensitive your nervous system is to caffeine. These genes have been identified in various studies by experts worldwide, including research from the Feinberg School of Medicine at Northwestern University in the U.S. The genes CYP1A2, AHR, POR, ABCG2, and CYP2A6 are responsible for metabolizing caffeine.

People with the right combination of these genes can process caffeine faster, so they feel the effects of coffee sooner. However, some people have difficulty digesting caffeine, which means even after drinking coffee, they still feel tired. This is because their bodies haven't fully processed the caffeine yet.

A meta-analysis published in Neuroscience & Biobehavioral Reviews found that consuming sugary snacks can cause fatigue in less than an hour. If you drink coffee that’s sweetened with cream, honey, syrup, or sugar, you may start to feel tired and drowsy.

When you consume more sugar than usual, your body produces insulin to offset the sugar intake. However, insulin also lowers blood sugar levels. As a result, when your blood sugar drops, you may feel drained and fatigued. You may also experience hunger, irritability, anxiety, sweating, dizziness, or nausea when your blood sugar levels dip.

Drinking a cup of coffee before bed can actually boost your energy levels. When you're feeling sleepy, your body produces adenosine, a chemical that promotes sleep. What you may not know is that caffeine blocks your brain from receiving adenosine. That’s why having coffee before a nap can leave you feeling refreshed and full of energy when you wake up.