Effect of Caffeine on Cognitive Function

Caffeine is a substance that elicits pharmacological changes in the human body. It is one of the most frequently ingested substances in the world, strongly imbedded in cultures worldwide in different forms. It is found in beverages like coffee, tea and soft drinks, in chocolate and in medication. The fact that it is widely consumed has evoked interest in the scientific community to research its effects on human health and function. Many people rely on a cup of coffee in the morning to the extent that some people are self-declared coffee addicts.

So what effect does this cup of energy have on our cognitive function? Caffeine is a central nervous system stimulant which noticeably makes one alert upon ingestion. It makes a person feel more awake, less tired, and provides a boost in energy levels within minutes. This is great for Monday mornings, for those who struggle with shaking off sleepiness once they wake up in the morning and for moments when you need to work through the night. However, research has shown that habitual drinking of coffee in the morning replaces the production of cortisol, a hormone naturally produced in high levels early in the morning to provide the body with a morning energy boost. It has been proven that delaying taking a cup coffee to 9am or 10am is better since cortisol levels would have gone down, and so, caffeine can now step in to boost someone's energy once again. Aside from inhibition of cortisol production, taking caffeine is also associated with hyperactivity and feelings of anxiety. Research shows that in excess amounts, caffeine over stimulates the brain.

Alertness and energy transforms to agitation, which impacts cognitive function negatively by making a person lose concentration on what needs to be done. This happens when caffeine is ingested in very high amounts. In a study done on the effect of black tea on human performance(Rizwan 2017), the conclusion drawn was that black tea consumption “speeded the performance, improved memory, reduced number of errors in the various cognitive tasks. . . even in small volumesblack tea consumption can speed up cognitive processing. ” The subjects were put through a battery of cognitive tests and findings revealed that drinking of black tea improved delayed memory recall which can be explained by caffeine's ability to increase a person's level of alertness. Additionally, the subjects who consumed caffeine were faster in the visual search task than their counterparts who were on a placebo since caffeine had increased their alertness and short term memory. This view is further supported by a review done by McLellan TM, et al. (2016) which stated that low tomoderate consumption of caffeine increases alertness, vigilance, attention, reaction time and attention. However, they did not note any improvement in memory. Another study however showed that regular coffee and black tea consumption had a correlation with the prevention of cognitive decline hence lowering the risk of Alzheimer’s and dementia. This is only possible if it is taken in reasonable amounts, within the daily intake limit since ingestion of too much coffee can over-stimulate the brain leading to confusion.

The study on black tea consumption further found out that caffeine had no effect on arithmetic calculation and memory span, i. e. . long term memory, but it did enhance iconic memory. In high amounts caffeine can be potentially harmful to human cognitive function; however, in moderate amounts, it’s ability to stimulate the brain to increase the level of alertness, short-term and reaction time is remarkable and should be embraced.