To begin with, I want to say that the effect of caffeine on the brain with modern science cannot yet be fully understood and explained easily. At every moment that you are awake, the neurons in your brain begin to become active. When these neurons become active, they produce adenosine as a product. But adenosine is much more than an excrement. Your nervous system actively monitors the adenosine levels via receptors. Normally when adenosine in your spine and in your brain reaches a certain amount, your body tells you that you are tired. There are different types of adenosine receptors in the human body, but caffeine is mainly related to the A1 receptor. Caffeine thus occurs in all kinds of plants and chemicals that resemble caffeine occur in your own body. The 100 mg caffeine that you get through a cup of coffee functions as an extremely talented adenosine imitator. The caffeine goes directly to the adenosine receptors in your body that is because of the similarities between caffeine and adenosine. Your body sees the caffeine as adenosine and therefore the caffeine ends up in the receptors. The caffeine really binds with the receptors, when the receptors are not activated, because the receptors are blocked. The own stimulating substances of the brain, dopamine and glutamate, can go their own way. There are other substances and receptors that have an effect on how your energy level feels like GABA. But caffeine is a way to prevent your brain from stopping things. “You can,” writes Braun, “only become so wired that your natural excitatory neurotransmitters support this.” In other words, you cannot use caffeine to completely eradicate a whole week of studying all week long, but you can use it to make yourself feel less tired by sleepy feelings in the morning. These effects will vary from person to person in length and strength. Depending on genetics, other physiological factors and tolerance. What is also important to know is that caffeine is not as simple as direct stimulant, such as amphetamines or cocaine; the effect on your alertness is much more subtle. Caffeine is one of the most used central nervous system stimulants, just like amphetamine and cocaine. By taking caffeine brain activity accelerates and makes a person more alert. As told, one of the reasons for drinking coffee is the light stimulating effect of caffeine on the central nervous system. It dispels sleep and fatigue, and improves concentration, reaction speed and endurance. A Dutch man is given a daily intake of 600 mg caffeine and the Dutch woman 500 mg caffeine. Most people get no side effects from this number of caffeine. The sensitivity of caffeine is different per person. A daily dose of up to 400 mg of caffeine is recommended for people who are sensitive to caffeine. Caffeine starts working after 15-30 minutes. Adenosine receptors are present in numerous places in the body.
(The structural formula of caffeine and adenosine)
For example in the brain, airways, heart, kidneys, fat cells, blood vessels and also in the gut tissue. If adenosine binds to the receptor, it makes you feel drowsy because it has a restoring effect on nerve cell activity. Caffeine connects with the adenosine instead of the adenosine binding to the receptor. Because the receptors are occupied, the cell no longer detects adenosine. This ensures that the brain becomes active again, just like the airways, the heart, the intestinal tissue and the kidneys. Fat is also burned and blood vessels become wider. These activities ensure the production of adrenaline, which accelerates the heart rate. Caffeine also influences the serotonin and dopamine system in the brain, which is why a coffee drinker feels comfortable.
Caffeine and work Johan Sebastian Bach loved coffee and there are many more, but in the kind of work that Bach did, consuming coffee did not benefit him. Most caffeine studies show that it can improve the work output but generally only for specific types of work. For tired people doing work that is relatively simple, this does not require much abstract thinking, but coffee has shown that it increases output and quality. Caffeine has also been seen to improve the creation and preservation of memories when it comes to ‘declarative memory’, which students use to remember lists or answers. This effect was only seen in morning tests, indicating that the subjects were either slightly dependent on caffeine, or at that time of the day were more inclined to perform such tasks. So we do not yet know very much about the effect of caffeine on work behavior.
Effective time of caffeine The effectiveness of caffeine varies considerably from person to person due to genetics and other factors that play. The mean half-life of caffeine, that is, how long it takes for half of the ingested dose to wear away, is about five to six hours in a human body. Women who use oral contraception need about twice as long to process caffeine. Women between ovulation and the onset of menstruation see a similar half-life. For smokers it takes half the normal time before the effect works out, which in some respects explains why smokers often drink more coffee and feel anxious because they are not aware of how their bodies work without cigarettes.
Caffeine tolerance If someone regularly starts taking caffeine, the body and mind build a tolerance for it. To get the same boost as the first time you drank caffeine, you always have to take caffeine. Exactly how that tolerance develops is not so clear. Many studies say that, as with any drug addiction, the brain strives to return to its normal function while being “attacked” by caffeine under caffeine, or by making more adenosine receptors. But regular caffeine use also appeared to reduce the receptors for norepinephrine, a hormone related to adrenaline, together with serotonin, a mood enhancer. A 1995 study showed that people become tolerant of their daily dose of caffeine, they had made two groups, in a group they started with one hundred mg of caffeine, and they increased this daily by ten, and in the second group they gave 900 daily. Mg of caffeine. After 18 days she discovered that the two groups were identical in behavior, energy and alertness. The group that took 900 mg did not feel that much anymore, but she felt it when they went from 900 mg to 0 mg caffeine
Adrenaline and dopamine Caffeine also influences the release of hormones, after an increase in the activity of adenosine receptors causes the pituitary gland to react by releasing hormones. These hormones ensure that adrenal glands produce adrenalin. This hormone ensures that the brain and body of the person is ready to defend themselves in an emergency, thus the person is very alert and can work quickly. As I said, caffeine increases the production of dopamine. Increased activity of dopamine is compared with other stimulant drugs such as amphetamine or heroin. Dopamine is a neurotransmitter that causes a feeling of reward and happiness.
Withdrawal symptoms You start to feel caffeine withdrawal very quickly, somewhere between 12 and 24 hours after your last use. That’s a big part of why that first cup or can is so important in the morning – it discourages the early effects of withdrawal. The reasons for the withdrawal are the same as for each substance dependency: your brain was used to working with caffeine in a way and now it suddenly works under completely different conditions, but all those changes in the receptor are still present. Headache is the almost universal effect of cutting off caffeine, but depression, fatigue, lethargy, irritability, nausea and vomiting can also be part of your cut-off, along with more specific problems, such as muscle spasms in the eye muscles. But in general you will be back in about ten days. Also, caffeine can cause the activation of frontal lobes, the consumption of caffeine activates the frontal lobes in the brain, these areas are responsible for the short-term memory and attention, and caffeine can thus increase these functions in a personThe long-term effects of caffeine are not as pleasant, long-term consumption of low doses of caffeine slowed down the functions of the hippocampus. This area in the brain is responsible for long-term memory and learning. So in a short time, caffeine can improve your alertness, but for a longer period of time it can also cause the deterioration of learning and memory.