How does coffee keep us awake?


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The first edible of the day in the life of an adult is a cup of coffee. Previously a premium drink served on special occasions, drinking coffee has now become a cultural commodity used particularly for social bonding. Several profitable businesses have been set up to serve nothing other than coffee because of the superiority of coffee over other beverages to facilitate social networking and interaction.

In India and even other countries, the first coffee of the morning is a customary routine, which has people claiming that their day cannot start without a cup of coffee. Although coffee was not designed to enable millions of people to be able to socialise over it, it has become an icon of culture. Coffee has so many variants and is so diverse than even young adults look forward to having it.

The main component in coffee which imparts the qualities which adults require to go to work daily is CAFFEINE. In basic terms, caffeine is the world’s most used DRUG. It is a STIMULANT for the CENTRAL NERVOUS SYSTEM (CNS) and that is the precise reason why humans gravitate towards the beverage of coffee or anything with caffeine in it – like tea or soft drinks.

The foremost trait associated with drinking coffee is the ability of the individual to stay awake and alert during the day. Caffeine is attributed to this since it affects the nervous system – thus gaining the term of a PSYCHOACTIVE DRUG. In the biological ecosystem, presence of caffeine (in a compound form) in nuts, leaves or the seeds of a plant gives it protection against predatory insects because it is a naturally bitter substance. The source of caffeine humans are provided with is from the seeds of the Coffea plant, commonly called as COFFEE BEANS.


The numerous brands which sell coffee powder engage in the refinement of the coffee beans, mixing of other flavours and packaging, which greatly reduces the bitterness of caffeine and gives the beverage (when mixed with water or milk) a desirable taste. However, people seldom drink coffee for its taste – they usually drink to benefit from the core impact of caffeine on their bodies. So, how exactly does caffeine stimulate the nervous system?

The ADENOSINE RECEPTORS are susceptible to the intake of caffeine. A receptor is a region for a specific molecule to dock – either to kickstart a reaction or to hinder one. In the case of adenosine receptors, a chemical molecule of ADENOSINE attaches to it to send a signal to the brain of the body being tired. As the adenosine molecules place themselves in their receptors, we feel sleepy. Chemically, adenosine is a PURINE, one of the major components in the DEOXYRIBONUCLEIC ACID (DNA) in our cells.

Adenosine is produced as a by-product of neuronal reactions in the body and is also involved in immunity and the major organ systems of the body. Thus, the formation of adenosine in the body (as a by-product) indicates that the body has performed a lot of its functions and is ready to rest. However, it is unpredictable when the body may decide when it is the time to rest – it maybe during a meeting at 11 A.M. or 7 P.M. Here is when caffeine enters the scene.

Caffeine is a STRUCTURAL and CHEMICAL ANALOGUE of adenosine. Structural analogue is a term used when two compounds are similar in their structure and/or their chemical composition. When coffee is consumed, the caffeine present in it enters the cells and substitutes the adenosine molecules on their receptors. Since caffeine and adenosine look like to a cell, the cell is unable to reject the entry of caffeine. This mechanism is true for nearly all the drugs and this is the property of drugs which is being exploited in the pharmaceutical industry to make medicines.


If adenosine were bind to the adenosine receptors, the activity of the NERVE CELLS would slow down, thus giving a drowsy feeling. In the cases of extreme fatigue, a higher concentration of adenosine is produced and so more adenosine receptors are also produced to bind to the excess molecules.

When caffeine binds to the adenosine receptors, the opposite reaction takes place. The nerve cell activity is either stabilised or increased – so the brain is tricked into believing that the body is rested and can carry forward. The adenosine molecules have nowhere to bind to. The cells, having recognised the adenosine molecules, deem them as ‘extra’ and raise more receptors on their surface.


This is one of the reasons why people may still feel tired and may need to consume more cups of coffee. This is a vicious cycle – as more adenosine molecules accumulate in the body, the more receptors would be generated. At such a point, one should restrict themselves from any more cups of coffee. A caffeine WITHDRAWAL may be experienced by the person (as observed in case of several other drugs), but the person’s body will revert to its normal state in a short while.

Is caffeine good or bad?

It is rather difficult to term a naturally occurring entity as good or bad. Caffeine protects the plants from insects – making it good for the plant and bad for the insects. Caffeine keeps a person awake and alert – making it good in moderation and bad in excess due to the withdrawal symptoms. The tolerance of a person to caffeine is heavily based on their genetics of the person.

Overdosing on caffeine is a real spectacle. The PITUITARY GLAND recognises a caffeine overdose as an emergency and puts the body in a FIGHT OR mode and releases adrenaline. This adrenaline causes the most common symptoms observed when someone consumes several cups of coffee – dilated pupils, faster heartbeat and rise in blood pressure. This condition ultimately puts the body in a highly alert and functional state but can be extremely lethal to it as well.

Thus, coffee is one of the most studied upon commodity in the food industry and even the study of narcotics. It is one of the only drugs which is legal worldwide and remains unregulated. The misuse or overuse of coffee will not only harm the individual consuming it but will also destroy several years of cultural routines.

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