Coffee is known worldwide for its stimulating effect, which helps us wake up and stay focused when needed. However, not everyone responds the same way to caffeine, the main active compound in coffee.
Some people may experience a paradoxical feeling of drowsiness after consuming coffee. But how can this happen? The answer lies in the complex interaction between caffeine and a neurotransmitter called adenosine.
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It is a neurotransmitter that increases throughout the day, contributing to the feeling of tiredness that we feel in the mid-afternoon or evening. It works as a signal to the brain that it's time to rest, reducing brain activity and dilating blood vessels.
Caffeine action: the opponent of sleep
In turn, caffeine acts by blocking adenosine receptors in our brain, preventing us from feeling drowsy. It's like the caffeine says "not today, adenosine!" and take over the body's warning system.
This effect is what makes us feel alert and energized after a cup of coffee. However, adenosine does not completely disappear while caffeine is in action.
Once the caffeine starts to wear off, the adenosine returns, and often with greater intensity. This “revenge” of adenosine can result in an even stronger feeling of drowsiness, a kind of rebound effect.
Caffeine tolerance: decreased stimulant effect
If you are a heavy coffee drinker, you may develop a caffeine tolerance. This means your body has become accustomed to the substance, and the stimulating effect wears off over time.
In such cases, drowsiness may return despite coffee consumption. To counter this, experts recommend decreasing consumption for a while to allow the body to process caffeine more efficiently.
It is important to note that each person reacts differently to caffeine. While some can drink several cups of coffee without feeling drowsy, others can experience drowsiness or other side effects such as heart palpitations even with a small amount.
These individual reactions can be influenced by a variety of factors, including genetics, metabolism and caffeine tolerance.