The Effect of Caffeine on Academic Performance
Sabryna Cadavillo, Dominican University New York
Abstract: Caffeine is classified as a stimulant – a drug that stimulates the brain and central nervous system – along with cocaine, methamphetamine, nicotine, and amphetamines, among others (“Stimulant,” 2024). The vast majority (91.1%) of undergraduate students regularly consume caffeinated drinks and products (Riera-Sampol et al. 2022). Students may associate caffeine use with academic study and may consider it an aid to academic performance due to its biochemical properties. But use of caffeine also produces negative biochemical effects such as jitters and increased anxiety. This study measured the effect of caffeine on subjects’ academic performance in terms of accuracy and speed. Due to the biochemical properties of caffeine, I hypothesized that the test performance of participants who have consumed caffeine will either remain the same or worsen. The study also surveyed participants about their perception of caffeine’s effects, the amount they consume daily, and their consumption on the day of the experiment. Results showed no correlation between caffeine consumption and improved academic performance.
The Effect of Caffeine on Academic Performance
Caffeine and Its Effects on Users
Caffeine, a widely-used stimulant, plays an important role in day-to-day life. While this drug does have medicinal properties and is used in analgesics and cough medications, caffeine is most commonly consumed in beverages such as coffee, tea, and soda. Due to the wide availability of these beverages, people may consume caffeine multiple times a day. Rodak et al. (2021) note that caffeine is absorbed through the small intestine, achieving “peak performance” at 30 minutes post-consumption, on average. The rapid absorption of caffeine by the small intestine means that it impacts bodily performance within 30 minutes after oral consumption. Because of the performance increase that caffeine gives the consumer, many age groups, including college students, drink some form of caffeine.
Rodak et al. (2021) reviewed the effects of caffeine to analyze its effect on multiple body systems and its effect on certain diseases. Caffeine is structurally similar to adenosine, which allows caffeine to bind to adenosine receptors. These receptors are then blocked, producing the common effects associated with caffeine consumption like increased alertness and wakefulness. Appropriate consumption levels of caffeine – 200 mg or less – have no adverse effects but surpassing 300 mg can cause symptoms of anxiety and jitters (Rodak et al., 2021).
Caffeine can affect multiple body systems, including the immune, digestive, respiratory, circulatory, urinary, and musculo-skeletal systems. Some of these effects are positive, some negative. In the immune system, caffeine reduces the inflammatory response; however, the necessary dosage to obtain this effect would be toxic to the body (Rodak et al., 2021). In the digestive system, caffeine helps with the breakdown of food through gastric acid and gastrin secretion but lowers enzymatic activity. The lowered enzymatic activity stimulates colon movement and suppresses inflammation and fibrogenesis (Rodak et al., 2021). In the respiratory system, caffeine may reduce symptoms associated with respiratory disease (Rodak et al., 2021). For example, caffeine consumption improves lung function for those with asthma. In the circulatory system, caffeine increases blood pressure which can lead to problems with cardiac function such as tachycardia and arrhythmias (Rodak et al., 2021). Caffeine’s effect on the urinary system includes diuresis (increased urine production) and natriuresis (increased sodium excretion). Caffeine has also been shown to decrease kidney stone formation and may help prevent renal fibrosis (Rodak et al., 2021). Finally, in the skeletal and muscle systems, caffeine can improve exercise performance. Caffeine’s effects on the body are numerous and these effects can be both positive and negative. The nature of the effects depends on additional factors including the age and gender of the consumer and the source and dosage of the caffeine consumed.
Caffeine also affects cognitive function. Studies have investigated caffeine’s effects on memory and behavioral performance. Lin et al. (2023) studied caffeine’s effects on working memory and behavior, finding multiple results: (1) a moderate dose of caffeine compromised working memory but did not produce any behavioral changes, (2) acute caffeine intake produced behavioral changes due to higher metabolic demand, and (3) caffeine withdrawal produced an impaired attention process, reducing hippocampal grey matter. Lin et al. (2023) also found that daily caffeine intake can inhibit the activity of the hippocampus during memory-related tasks. In a study of chronic caffeine users, Pavia et al. (2022) noted that chronic caffeine consumption affected RNA transcriptomes through an enhancement of different genes in the bulk hippocampus. This suggests that caffeine helps in cognitive function (Pavia et al., 2022). Based on the results of this study, regular caffeine consumption can lead to changes in synapses and neural activity in the brain. While promising, it is important to note that this study was done on mice in comparison to Lin et al. (2023) who focused on human participants.
The Role of Genetics in Caffeine’s Effects
Genetics can play a role in how caffeine affects a drinker’s digestive system. Zhou et al. (2018) conducted a genetic study that examined the link between caffeine intake, genetics, and cognitive function. The associations of focus are “genetically instrumented habitual coffee intake, and cognitive function in mid- to later-life, with the aim of establishing causal evidence for potential long-term cognitive effects of coffee consumption” (Zhou et al., 2018). Genetic analysis in this study focused on eight loci: CYP1A1/2, AHR, POR, EFCAB5, GCKR, ABCG2, MLXIPL, and BDNF. Loci are the positions of either the gene or mutation on a chromosome. Zhou et al. (2018) focused on the first two loci, as CYPA2 accounts for ~95% of caffeine clearance in the kidney with AHR playing a role in caffeine’s metabolism and the transcription of CYPA2. To study caffeine intake, participants self-reported the amount they drink. Cognitive function analysis was studied using different tests such as the Mini-Mental State Examination (MMSE), Trail Making Tests, Digit Symbol Coding, and the Paired Associates Learning test. Study results showed no evidence to support any beneficial or long-term effects of coffee consumption regarding cognition or memory, thus also suggesting that there is no genetic link between caffeine consumption and memory. Zhou et al. (2018) also found that CYPA2 and AHR are prevalent in habitual caffeine drinkers, suggesting an association between genetics and caffeine consumption.
Assumptions about Caffeine’s Influence on Academic Performance
Because caffeine can improve alertness and decrease the symptoms of fatigue, college students may assume that caffeine consumption also has a positive impact on academic performance. Students widely consume caffeine: one study (Riera-Sampol et al., 2022) found that 91.1% of participants consumed caffeine. Reasons reported for caffeine use were cognitive enhancement, negative affect relief, reinforcement effects, and weight control (Riera-Sampol et al., 2022). Other studies have found a similar association between caffeine use and academic performance. Idoko et al. (2023) noted that 56.7% of their study participants consumed caffeine, but the frequency of substances (whether caffeine or drugs) increased during exam periods, presumably to help students stay awake and alert for studying purposes. Khan et al. (2017) reported that their participants consumed caffeine for reasons including improved academic performance, overnight study, self-confidence, and social purposes. Lucke et al. (2018) found that most participants consumed caffeine to help improve or prolong academic performance, while an additional 177 participants abused prescription stimulants to help increase academic performance. All three studies (Idoko et al., 2023; Khan et al., 2017; & Lucke et al., 2018) found that participant use (and, potentially, abuse) of caffeine rested on the assumption that caffeine would help them do better academically by helping them stay awake and keeping them alert.
Methodology
This study investigated caffeine’s effects on academic performance as well as student assumptions about caffeine’s effects on academic performance. Students were recruited from the Dominican University’s SONA pool. To test caffeine’s impact on academic performance, participants took a timed test. A questionnaire was used to gather information about student attitudes toward caffeine.
Participants
The experiment recruited a total of 31 participants from Dominican University New York’s SONA pool with 16 female and 15 male participants. Screening questions were used to eliminate potential participants who have never consumed caffeinated products or have vision problems that might confound their performance on the online test.
Design
Participants were divided into two groups. The experimental group consumed Mio Energy, a sugar-free drink mix that contains 90 mg of caffeine. This dosage of caffeine was chosen for three reasons: (1) ready availability at a local pharmacy, (2) the caffeine dosage was within the appropriate consumption level at less than 200 mg, and (3) it eliminated sugar as a confounding factor. The control group consumed Mio Sugar-Free, a flavoring for water that is both caffeine and sugar-free. As a motivational factor, participants were told that a $20 Dunkin Donuts gift card would be given to the participant with the best test performance. In the end, participants were made aware of this deception and were allowed to participate in a random phone number drawing to win the gift card. All participants were given an initial questionnaire about their use of caffeine, their reasons for consuming caffeine, and their perception of the effects of caffeine on their mind and body.
Procedure
A 75-question test and 26-item questionnaire were made through Microsoft Forms and shared with participants via Microsoft Teams. Participants were split into two groups: Non-Caffeinated (A) and Caffeinated (B) (see Figure 1 below). Participants were self-selected into a group through their choice of drink cup. The non-caffeinated group were those who chose a cup filled with Mio Fruit Punch made with 1 teaspoon of the flavor additive (per package instructions). The caffeinated group were those who chose a cup filled with Mio Black Cherry Energy made with ½ teaspoon of flavor additive (per package instructions). After consuming the Mio beverage chosen, participants were asked to complete a 26-item questionnaire on Microsoft Forms (see Appendix – Caffeine Perception Questionnaire). These questions asked participants about their perceptions of caffeine. The time participants took to complete the questionnaire was between 10 – 20 minutes, allowing for the caffeine to be absorbed. Although peak performance is estimated between 30 – 45 minutes (Rodak et al., 2021), time constraints for the study only allowed for 10 – 20 minutes for caffeine absorption and distribution. After completing the questionnaire, participants were then asked to take a timed examination (general trivia), completing as many questions as possible in 15 minutes.
Results
Questionnaire Findings
Questionnaire data was analyzed using Excel and Microsoft Forms through a given generated rundown from Forms. Participants were asked to answer each question on a 4-point scale, with 1 as “not likely” and 4 as “very likely.”
While a previous study conducted by Riera-Sampol et al. (2022) found that 91.1% of participants reported the assumption that caffeine improved their academic performance, in the present study, only 35% of participants reported this assumption. Surprisingly, 65% of this study’s participants felt that drinking caffeine does NOT help them perform better academically (see Figure 2 below). The most common reasons for caffeine consumption reported in this questionnaire are for the taste (84%) and to combat drowsiness (71%). In response to questions about caffeine’s effects on the body and mind, participants generally noted that they experienced common symptoms such as increased diuresis (61.3%), jitters (61.3%), and anxiety (42%) with caffeine intake.
Test Questions and Participant Response
A test was administered to all participants to assess the effects of caffeine on simulated academic performance. The 75-question multiple-choice test had general trivia questions on topics ranging from geography, art, literature, science, English, math, everyday life, to random facts. Several errors in the creation of the test created problems for data analysis. First, due to anonymity during the questionnaire and test completion, participants’ questionnaire responses could not be linked to their test scores. Another creation error involved a question that had no correct answer. This question was removed from analysis. Participants reported that they found the questions relating to literature and geography difficult. Many participants had mixed feelings about the test, some reporting that “it wasn’t so bad” while others described the test as “extremely hard.”
Data Analysis
Participant performance on the test was evaluated through Microsoft Forms and Excel. The test had a question asking participants which cup they took to distinguish those who consumed caffeine and those who did not. The multiple-choice format of the test allowed for easy grading with Microsoft Forms tracking the time it took for participants to finish the test. Results showed only slight differences between the caffeine and non-caffeine groups in terms of overall score and time to completion. The caffeine group answered more questions accurately. The average score for the non-caffeinated group is 49.6%, while the average score of the caffeinated group is 52.8% (see Figure 3 below). The caffeine group completed the test more quickly. On average, the non-caffeinated group took around 10 minutes and 15 seconds to finish while the caffeinated group took 9 minutes and 15 seconds to finish (see Figure 4 below).
Data was also analyzed by removing outliers in the data (i.e., the one participant who did not finish within 15 minutes) through a 10-sample group. Overall scores for the non-caffeinated group in this analysis was 47.1% with the caffeinated group at 53.5% (see Figure 5 below). Times for the non-caffeinated group was 11 minutes and 31 seconds with the caffeinated group taking 10 minutes and 15 seconds to finish the test (see Figure 6 below).
Analyzing the score and time results on Excel through a t-test shows a p-value > α (α = 0.05) thus the null hypothesis is accepted. Overall, while the p-value was higher than 0.05, there is an observed trend that participants who consume caffeine tended to perform better and finish quicker when taking the test.
Discussion
The results of the current study demonstrated no correlation between caffeine consumption and academic performance. Data gathered through questionnaire results reproduce results found in previous studies (Idoko et al., 2023; Khan et al., 2017; Lucke et al., 2018; & Riera-Sampol et al., 2022) with caffeine being consumed for taste, increased alertness, and wakefulness.
Limitations were numerous, including the small sample size and the errors in the questionnaire and test design. Four participants in the experimental group (those who consumed caffeine) appeared to answer questions haphazardly. These same participants incorrectly answered the attention questions in the questionnaire, suggesting that these participants did not take the test seriously and filled in random answers. However, due to a flaw in the study design, these haphazard test results could not be isolated from the other results, potentially impacting the analysis of data. Rodak et al. (2021) stated that it takes 30 – 45 minutes for caffeine to be absorbed by the small intestine for peak performance. Due to time constraints, participants had to take the test within 10 – 20 minutes after caffeine consumption, thus the caffeine may not have fully taken effect before the test was administered.
Future studies should include a larger sample size, as the current study only involved 31 participants which lead to high p-values in the data analysis. Future studies might also recruit participants from different age groups, as most of the current study’s participants were first-year undergraduate students. Studying caffeine’s effects in different age groups would be interesting as the recommended caffeine consumption differs by age group. Understanding how the same dosage of caffeine can affect these age groups would be interesting when considering tolerance levels. Riera-Sampol et al. (2022) report that women metabolize caffeine 20 – 30% faster than men, so a future study might consider the biochemical role of gender in both the effects of caffeine and assumptions about its effects.
Ultimately, the results of this study showed no statistically significant relation between caffeine and academic performance. The caffeine group did not perform significantly better on the test either in terms of overall score or time to completion. The questionnaire results suggest that while participants associate caffeine use with increased wakefulness and attention, they do not necessarily think that this improves their academic performance.
References
Idoko, C. A., Chidolue, I., Idoko, C. I., Eze, C. K., & Ucheya, E. (2023). Substance abuse among medical students of a Nigerian University: Prevalence, factors influencing use, and effects on academic performance. International Journal of Medicine and Health Development, 28(2), 156. https://journals.lww.com/ijmh/fulltext/2023/28020/substance_abuse_among_medical_students_of_a.12.aspx
Khan, M. S., Nisar, N., Naqvi, S. A. A., & Nawab, F. (2017). Caffeine consumption and academic performance among medical students of Dow University of Health Science (DUHS), Karachi, Pakistan. Annals of Abbashi Shadeed Hospital and Karachi Medical & Dental College, 22(3), 179-184. https://doi.org/10.58397/ashkmdc.v22i3.126
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Lin, Y., Weibel, J., Landolt, H., Santini, F., Slawik, H., Borgwardt, S., . . . Reichert, C. F. (2023). Brain activity during a working memory task after daily caffeine intake and caffeine withdrawal: A randomized double-blind placebo-controlled trial. Scientific Reports (Nature Publisher Group), 13(1), 1002. doi:https://doi.org/10.1038/s41598-022-26808-5
Lohsoonthorn, V., Khidir, H., Casillas, G., Lertmaharit, S., Tadesse, M. G., Pensuksan, W. C., Rattananupong, T., Gelaye, B., & Williams, M. A. (2013). Sleep quality and sleep patterns in relation to consumption of energy drinks, caffeinated beverages, and other stimulants among Thai college students. Sleep & breathing = Schlaf & Atmung, 17(3), 1017–1028. https://doi.org/10.1007/s11325-012-0792-1
Lucke, J., Jensen, C., Dunn, M., Chan, G., Forlini, C., Kaye, S., Partridge, B., Farrell, M., Racine, E., & Hall, W. (2018). Non-medical prescription stimulant use to improve academic performance among Australian university students: prevalence and correlates of use. BMC Public Health, 18(1). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6245847/
Paiva, I., Cellai, L., Meriaux, C., Poncelet, L., Nebie, O., Saliou, J.-M., Lacoste, A.-S., Papegaey, A., Drobecq, H., Gras, S. L., Schneider, M., Malik, E. M., Muller, C. E., Faivre, E., Carvalho, K., Gomez-Murcia, V., Vieau, D., Thiroux, B., Eddarkaoui, S., ...Blum, D. (2022). Caffeine intake exerts dual genome-wide effects on hippocampal metabolism and learning-dependent transcription. Journal of Clinical Investigation, 132(12), NA. http://dx.doi.org.libdb.dc.edu/doi.org/10.1172/JCI149371
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Appendix
Caffeine Perception Questionnaire
What is your sex?
(a) Male
(b) Female
What is your age?
______
Are you of Hispanic or Latino origin?
(a) Yes
(b) No
What is your race?
(a) White
(b) Black or African-American
(c) American Indian or Alaskan Native
(d) Asian
(e) Native Hawaiian or other Pacific Islander
(f) Mixed Race
(e) Other: _______________________
What year are you in?
(a) Freshman
(b) Sophomore
(c) Junior
(d) Senior
Did you drink caffeine today before coming to the study?
Yes
No
Please circle one number with 1 being not likely to 4 being very likely.
I drink a caffeinated beverage (coffee, tea, soda, energy drink) every day.
1 2 3 4
Not Likely Very Likely
I drink MORE THAN ONE caffeinated beverage every day.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage because I feel like I perform better in my studies.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage because it increases my attention span.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage to stay awake.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage to combat drowsiness.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage to combat headaches.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage to relax.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage because of the taste.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage because of the buzz it gives me.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage because it keeps me alert.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage because it is easy to obtain/buy.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage because the people around me are drinking it.
1 2 3 4
Not Likely Very Likely
I drink a caffeinated beverage because of cravings.
1 2 3 4
Not Likely Very Likely
Drinking a caffeinated beverage makes me anxious or more anxious.
1 2 3 4
Not Likely Very Likely
Drinking a caffeinated beverage makes me tired or more tired.
1 2 3 4
Not Likely Very Likely
Drinking a caffeinated beverage gives me headaches.
1 2 3 4
Not Likely Very Likely
Drinking a caffeinated beverage makes me use the bathroom more.
1 2 3 4
Not Likely Very Likely
Drinking a caffeinated beverage makes me antsy or unable to sit still.
1 2 3 4
Not Likely Very Likely
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