Caffeine is a bitter xanthine alkaloid that acts on humans as a psychoactive stimulant. Caffeine naturally occurs in many plants, but humans generally consume it mostly from the beans of the coffee plant. In nature, caffeine is a natural pesticide produced by plants. It serves to protect the leaves, fruits and flowers from various insects. Insects are driven away by the bitter taste of caffeine. On humans, caffeine has a quite different effect. It stimulates the central nervous system and provides a lot of benefits such as pain relief, restored alertness and release from the sleepiness. However, the effects of caffeine are just temporary, and the body will soon need another dosage in order to remain fresh and vigorous. Unfortunately, excessive caffeine consumption results in caffeine resistance which further leads to overuse and intoxication. Breaking the chain of addiction is not an easy job, since the reduction in caffeine intake results in unwelcome withdrawal symptoms. Let us take a closer look at this serious health problem.
Caffeine acts upon the central nervous system’s receptors for the neurotransmitter adenosine. The caffeine molecule is structurally similar to the aglycone of adenosine, which is also involved in the control of the sleep-wake cycle, and other metabolic processes. People who consume caffeine on a regular basis and in excessive quantities can easily become dependent on the presence of the substance. At the same time, the number of the adenosine receptors in their central nervous system will increase. This way, a reduction in caffeine intake will effectively increase the normal physiological effects of adenosine, resulting in unwanted withdrawal symptoms.
Caffeine withdrawal symptoms
Caffeine tolerance can develop very quickly. Scientists estimate that the total tolerance to the sleep interruption effects of caffeine develops after consuming 400 mg of caffeine 3 times a day for a week. To develop a complete tolerance to subjective effects of caffeine it takes 300 mg 3 times per day for 18 days, in some cases even earlier.
Caffeine withdrawal symptoms may be very severe. The increased effects of adenosine may cause the blood vessels of the head to dilate. This results in the increased blood flow to the head and causes severe headache and nausea. Another unwanted symptom is the feeling of fatigue, often accompanied with drowsiness. Caffeine withdrawal also causes lower serotonin levels and causes anxiety, irritability, and problems with concentration, low motivation or even milder depression.
Other symptoms include abdominal pain, pain in the upper body, and joint ache. The symptoms are the most severe after 48 hours, and they usually last from one to two days. The best way to fight against these symptoms is to take controlled doses of analgesics.