Caffeine, found in coffee, tea and other beverages or delicacies such as chocolate, promotes brain stimulation and alertness in most people. The biological mechanisms that cause drowsiness and sleep deprivation, as well as how caffeine prevents them, have not been fully understood to date.
Understanding these mechanisms is important because it can have practical applications in treating insomnia and other sleep disorders.
It is also possible to have practical applications in occupational medicine, shift workers and in the prevention of drowsiness accidents.
When the cells of an area of the brain work too hard, a substance is released which signals that they need to enter a state of rest with a substantial reduction in their function.
This substance, which causes drowsiness and sleepiness, is called adenosine. The action of adenosine is suppressed by caffeine. This is why people who drink coffee, tea or other caffeinated beverages can stay awake for longer.
Adenosine acts as a biological fatigue agent. In brain stimulation centers, neurons communicate with each other, process information, and coordinate all of a person’s activities. These centers control the activity of the whole brain.
The constant activity of neurons increases the concentration of adenosine. It is a control mechanism that forces the cells, through sleep, to rest and rejuvenate.
In cases where there is a disturbance in the adenosine control system in the brain, insomnia may be caused.
Insomnia and chronic sleep deprivation are very common problems that plague modern man. In addition there are many mental illnesses that are accompanied by insomnia. Depression, schizophrenia, and post-traumatic stress disorder are characterized by significant sleep disturbances.
Consumption of caffeine, from any source (coffee, tea, chocolate, soft drinks), suppressing the adenosine system in the brain, inhibits sleep. Caffeine easily crosses the blood-brain barrier.
Caffeine also delays the onset of fatigue during prolonged exercise. It has been estimated that caffeine consumption, from 3 to 9 mg / kg body weight can increase the exercise time that can be performed by 50%.
So we see that drowsiness, sleep and fatigue are controlled by a complex system of neurotransmitters, which control the activity of brain stimulation centers with adenosine as the main protagonist, which creates the feeling of fatigue and need for sleep.
The investigation of abnormalities of this system, the role of exogenous factors, such as caffeine are of great interest and may have practical applications for human health and activities.