Coffee, tea and cocoa beans all contain the chemical caffeine. This chemical has a similar structure to a chemical in the human brain called adenosine. Adenosine is released by the body when it is tired. It attaches to specific sites in the brain to slow down nerve cell activity to bring on drowsiness and makes the blood vessels in the brain wider (dilate) to increase the amount of oxygen taken to the brain while the body sleeps.
Caffeine prevents this taking place by binding to the sites and blocking the adenosine. This prevents the drowsy feeling but also the brain gets used to not having the blood vessels dilated when the body is tired due to regular caffeine consumption.
When we decide to give up caffeine this is reversed. Adenosine freely attaches to previously blocked sites and the blood vessels in the brain dilate more than ever, causing splitting headaches.
Caffeine prevents this taking place by binding to the sites and blocking the adenosine. This prevents the drowsy feeling but also the brain gets used to not having the blood vessels dilated when the body is tired due to regular caffeine consumption.
When we decide to give up caffeine this is reversed. Adenosine freely attaches to previously blocked sites and the blood vessels in the brain dilate more than ever, causing splitting headaches.
