Caffeine is a popular stimulant that helps people to get up and going in the morning. It helps them to wake up and feel alert, and it increases concentration and productivity. Caffeine however, is very addictive and a withdrawal from it often causes headaches, including severe migraines. The headaches usually occur within 12 to 24 hours from the time the last dose of caffeine was taken, and can last anywhere from three to nine days, depending on how bad the individual is hooked on the caffeine.
According to a study done at the John Hopkins School of Medicine, the headaches occur as a result of changes in the brain’s electrical activity and changes in the blood flow to the brain. Caffeine constricts blood vessels, and thus stopping caffeine increases the blood flow, which is said to be a factor in causing the headaches.
Other studies have shown that caffeine has a molecule similar to a neurotransmitter, known as adenosine. Since the molecule is similar, it is able to fit perfectly into the adenosine receptors and thereby block the effects of adenosine. Caffeine and adenosine may have a similar molecule, however they have total opposite effects on the body.
Caffeine can cause the blood vessels to constrict, and thereby it increases the release of neurochemicals, which stimulate the body. Adenosine acts as a natural tranquilizer or painkiller when it is within the nervous system, and outside of the nervous system it can cause pain such as headaches and migraines. In large quantities, it can cause the blood vessels to dilate, particularly in the head and neck areas.
When caffeine is consumed for a long period of time, the body becomes more sensitive to adenosine, as the adenosine receptors are occupied by caffeine. This causes the body to release more adenosine and activates more receptors. In addition, the body also slows down the rate at which the adenosine is eliminated from the body. According to medical findings, those who suffer from headaches have higher numbers of adenosine circulating around the head and neck area.
As a result, caffeine can cause headaches and migraines when it is taken in excess amounts, as well as when it is stopped abruptly. A caffeine withdrawal headache is an indicator that too much caffeine is consumed, and the individual should consider reducing the amounts gradually. The headaches caused by caffeine withdrawal are generally harmless, as they will go away as soon as caffeine is reintroduced into the body, or when the effects of it wear off in the body.