Why a Headache After a Day of Not Drinking Coffee?

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Missing your morning coffee may not seem like a big deal until you develop a headache that feels like a beating drum in your temples. Even worse, your caffeine-withdrawal headache may be accompanied by other unpleasant symptoms like fatigue, difficulty concentrating, mood changes and feeling like you have the flu.

The Headache of Caffeine Withdrawal

A caffeine-withdrawal headache causes a throbbing sensation on both sides of the head and occurs within one day after the last caffeine intake. It may occur in people who consume 2 or more cups of coffee daily. Relief of this headache occurs within one hour of consuming 100mg of caffeine -- about one cup of coffee -- or within one week after complete caffeine withdrawal.

The Science Behind Caffeine Withdrawal

Caffeine binds to adenosine receptors in the brain. Adenosine is a chemical that slows down nerve cell activity in the brain, which makes you feel drowsy. Caffeine also binds to these same receptors, blocking out adenosine. This causes an increase in nerve activity, creating the energizing effect of caffeine.

In response to caffeine intake, scientists believe the brain adapts by increasing the number of adenosine receptors. So when you miss your cup of coffee, you now have an increased amount of adenosine-bound receptors. This causes blood vessels in the head to dilate, creating a withdrawal headache.

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