Serendip is an independent site partnering with faculty at multiple colleges and universities around the world. Happy exploring!

Effects of Caffeine

Yashaswini's picture
Caffeine, The Wonder Drug?
I grew up watching my father work late nights in his study, draining 5-6 mugs of coffee in rapid succession. I grew up hearing marvellous tales about a wonder-drug called caffeine that all the ‘grown ups’ took, that enabled them to stay up late and do innumerable things without getting tired! The first time I had coffee, I hated it –it was an oppressing shade of brown, smelt like rancid cocoa beans and tasted grotesquely bitter! However, over the years, as my workload increased, I found it increasingly difficult to stay energised enough all day long and used to get enervated really soon. This was when I started taking the ‘wonder-drug’ in various forms – caffeinated sodas, tiramisu, and the good old coffee – and before soon, caffeine had become a vital part of my daily existence!
Caffeine is a substance that is found in varying quantities in the beans, leaves and fruits of certain plants. It is found artificially in tea, coffee, many sodas, energy drinks, chocolates and even a few medicines (! Though some consider caffeine to be an instant mood-elevator, I feel caffeine to be a drug, no less dangerous than cocaine or nicotine. In a quintessential addiction-scenario, regular intake of caffeine prevents us from experiencing depression and fatigue associated with its withdrawal. However, when regular coffee drinkers are denied their daily intake, they experience acute withdrawal symptoms, descbed furthur down. Caffeine has different effects on different people, most of which can be summarised as follows.
Caffeine does play the part of a wonder-drug to a certain extent. It boosts our energy and banishes any signs of drowsiness and feelings of fatigue. It stimulates the cortex of the brain to produce more of the neurotransmitter, adenosine, a molecule that aids in the transfer of nerve impulses. As adenosine binds with its receptor, nerve cell activity slows down, causing relaxation and drowsiness. To a nerve cell, caffeine and adenosine look alike! Thus, when caffeine binds to the adenosine receptor, it not only prevents the cell from identifying adenosine by blocking the receptors, but also abstains from slowing down the cell’s activity like adenosine would. Thus, instead of nerve activity slowing down, it speeds up. The increased neuron activity sends signals to the pituitary gland, which in turn sends signals to the adrenal gland to produce adrenaline, the “fight or flight” hormone. Adrenaline has many effects on the body such as faster heart rate, increased blood pressure and constriction of muscles ( This is probably why after drinking a cup of coffee, our mental alertness increases many fold!
However, it is imperative to mention that once the effect of the adrenaline wears off, we face fatigue and depression. To counter this, we consume more caffeine to get the adrenaline going again. This results in a vicious cycle and brings up the issue of caffeine tolerance. Tolerance refers to the body's "getting used" to a drug with its repeated intake. With increased quantity and frequency of caffeine intake, tolerance towards it increases. Thus, after a certain period of time, the same dose of caffeine produces a reduced effect (which in turn increases the desire to consume more caffeine, which further increases its tolerance) and a larger dose is required to produce the same level of effect.
Caffeine also urges glucose to be released from its storage temporarily. This burst of glucose in our body gives us a temporary high and we are upbeat about everything. However, this overworks the pancreas that now has to produce extra insulin to reduce the extra glucose in our body. After the blood sugar has been countered with insulin, our vitality level comes back to normal and the temporary. Once the extra insulin has negated the extra blood sugar our temporary lift from the caffeine ends and our vitality level is back to normal. Many times, with frequent intake of caffeine, the pancreas gets accustomed to producing large quantities of insulin. Thus, as a result the insulin negates not just the excess blood sugar but the blood sugar we need to feel alert and energetic. The initial effect of this is a let-down effect and it leads to the body craving for more caffeine to give the mind a further boost (
            Another effect of excessive caffeine consumption that I personally experienced was sleep-deprivation. Despite having physically and mentally exhausting days, I used to find it exceptionally hard to find deep REM sleep. This can be explained as follows: Caffeine stimulates the nervous system till a point where it is too engaged and active for us to have a deep and restful sleep. Also, since caffeine interferes with the functioning of the adenosine-receptor imperative for a deep, prolonged sleep, it is no surprise that caffeine-addicts find it nearly impossible to get a good night’s rest. This also has to do with the half-life of caffeine, which is the number of hours for which the effects of caffeine are present in the body. This is typically 6-8 hours. This means that even after 6 hours of having a caffeinated drink, half of the caffeine remains in our body system. Despite this, however, we might manage to get a few hours of light sleep. Even though we might be able to fall asleep, our body misses out on the benefits of a well-rested night’s deep sleep and feels tired and exhausted the following morning, which again, can be made better only by consuming more caffeine, which further worsens the sleep-scenario! This turns into a vicious cycle which forces us into consuming caffeine, in some form or the other, everyday! And if we address our addiction and try to stop consuming coffee, we are faced with severe “withdrawal symptoms” including but not limited to splitting headaches, lethargy, reduced concentration, dilating blood vessels, irritability, anger and overall restlessness.
Few months back, I had developed anaweful habit of substituting breakfast with a mug of coffee. But last week, while preparing for this paper, I learnt that caffeine on an empty stomach can have nasty consequences! Not only does it irritate the stomach lining, but it also stimulates acid secretion in the digestive tract. This in turn increases stomach acidity and enhances the chances of developing peptic ulcers! After knowing this, I now make it a point to never skip breakfast anymore.
Caffeine, as we can tell, is most definitely a drug. It enhances our senses, makes us more alert and upbeat. Regular coffee drinkers are 80 percent less likely to develop Parkinson’s disease. Caffeine also acts as a carcinogenic as drinking two cups of coffee a day reduces the risk of colon cancer as well! However, it also enhances stress, fatigue and insomnia in us. Too much caffeine intake will not only disrupt sleep patterns, but also kill appetite. With caffeine, moderation is the key.


Paul Grobstein's picture

life and moderation ....

"With caffeine, moderation is the key."

Maybe that's true of all aspects of being alive (such as u-shaped curves for temperature and pH, as per lab).  I wonder why?