Res. Assist. Ekin Çevik from the Department of Nutrition and Dietetics at Üsküdar Üniversitesi addressed the issue of coffee and energy drinks, which students turn to in the hope of increasing their cognitive performance on the morning of and before the Higher Education Institutions Exam (YKS) to be held on June 21-22.
Caffeine, the most widely used central nervous system stimulant worldwide
Stating that students increase their consumption of caffeinated beverages to increase alertness, overcome fatigue, cope with stress, and improve cognitive performance during the upcoming exam, Ekin Çevik said, "Caffeine is the most widely used central nervous system stimulant and psychoactive substance worldwide, and it is estimated that more than 80 percent of the world's population consumes caffeine. A recent study shows that caffeine consumption mostly takes place at home, and the most consumed caffeine sources are coffee, tea, energy drinks, and soft drinks."
Coffee or energy drinks do not provide energy, they suppress the feeling of fatigue
Explaining that the main active ingredient in coffee and energy drinks is caffeine and that it exerts its effect by stimulating the central nervous system, Ekin Çevik continued:
"The most prominent effect of caffeine is to temporarily block the effect of a chemical called adenosine, which affects many processes in our brain such as sleep, attention, memory, and learning. Normally, adenosine accumulates during the day, making us feel tired and sleepy; however, after consumption, caffeine occupies the receptors to which adenosine binds, blocking its effect. Since nerve cells cannot distinguish caffeine from adenosine, caffeine steps in at this point and creates a stimulating effect. This allows one to feel more energetic, awake, and focused for a short time after caffeine intake. The stimulating effects of caffeine begin approximately 15-30 minutes after consumption and can last for several hours. However, what we call energy is actually the fuel provided by the body through real nutrients. Coffee or energy drinks do not provide energy; they only suppress the feeling of fatigue. This is a temporary illusion."
Energy drinks can cause fatigue and anxiety when consumed in high doses
Ekin Çevik noted that taurine, another important component found in energy drinks in addition to caffeine, also functions as an inhibitory neuromodulator on the nervous system. "Taurine plays a balancing role by preventing excessive stimulation in nerve cells. Therefore, the use of taurine in energy drinks aims to achieve a more stable response on cognitive performance by balancing the stimulating effects of caffeine. Furthermore, taurine can create indirect effects on cognitive functions, learning, and memory by regulating intracellular calcium balance and affecting synaptic transmission. When consumed in high doses, it can cause fatigue and anxiety with the opposite effect. It is stated that taurine may also have effects on the brain, heart, and skeletal muscle due to its effect on calcium release," she said.
Excess sugar can also cause sudden fatigue during the exam
Ekin Çevik also stated that some instant coffees and energy drinks contain high amounts of sugar, adding:
"Simple sugars (especially glucose) that enter the bloodstream after consumption are used as the brain's main energy source, and this can lead to a short-term improvement in cognitive processes such as attention, memory, and reaction time. This effect can be more pronounced, especially when hungry or after prolonged mental fatigue. However, the rapid insulin release that follows this sudden energy boost, which starts with simple sugars rapidly entering the bloodstream, lowers blood sugar levels and results in sudden fatigue, weakness, irritability, and difficulty concentrating, known as a 'crash'. If this effect occurs during an exam, it can lead to a severe impairment of cognitive performance. This effect is generally felt more intensely in energy drinks because, in addition to sugar, they also contain high doses of caffeine. Caffeine masks this energy boost by providing short-term alertness; however, when its effect wears off, both low blood sugar and adenosine accumulation combine to make the crash deeper and more uncomfortable. This dual effect is the main reason for the sudden exhaustion felt after energy drinks."
On a full stomach 1 hour before the exam
Ekin Çevik also stated that the recommended safe upper limit for caffeine intake is limited to 400 mg/day, and this amount generally corresponds to 2-3 cups (1 cup=240-250 mL) of filtered coffee. "For individuals with health problems such as heart rhythm disorders (arrhythmia), hypertension, and anxiety, caffeine consumption should be limited to 100-200 mg/day. On the other hand; 200–300 mg of caffeine is considered an effective and safe range to support the cognitive functions such as attention, memory, and focus of healthy individuals during the day. This corresponds to 1-2 cups of filtered coffee or 2-3 cups of Turkish coffee daily. Especially energy drinks, while containing 80 to 320 mg of caffeine per serving, also stand out with their high sugar content. Therefore, their regular use is definitely not recommended; only single and low-dose consumption is advised. Although caffeine temporarily increases attention and alertness, it does not truly provide energy. For this reason, it is recommended that coffee or energy drinks be consumed at least 1 hour before the exam and on a full stomach," she said.
Can cause palpitations during the exam!
Emphasizing that excessive caffeine consumption can create undesirable effects such as palpitations, sweating, restlessness, and anxiety during the exam, Ekin Çevik said, "Especially excessive consumption of energy drinks can lead to a state of overstimulation that makes it difficult to focus. Unconscious consumption of these drinks can lead to negative consequences for both cognitive functions and general health in the long term, due to the caffeine, sugar, and other stimulating substances they contain. Excessive caffeine habit can lead to disrupted sleep patterns, increased stress hormones, and decreased retention of learned information. This negatively affects both academic success and general health. From a cardiovascular perspective, both caffeine and taurine can increase heart rate and blood pressure. While these effects are moderate in healthy individuals, the risk is greater in children, adolescents, and individuals with low body weight. Therefore, in many countries, the sale of energy drinks to young individuals has been restricted or banned. The increased stimulating effects of caffeine and taurine on the heart when taken together further increase the potential danger of these drinks."
In some countries, the sale of energy drinks to those under 18 is prohibited
Stating that adolescence is a critical period during which brain and nervous system development continues, hormonal balances change, and behavioral habits are shaped, Ekin Çevik said, "Excessive or unconscious consumption of energy drinks in this age group can lead to short-term effects such as heart palpitations, blood pressure fluctuations, sleep disturbances, irritability, anxiety, and addiction risk, as well as long-term negative effects on brain development and stress coping capacity. In addition, young people's sensitivity to stimulating compounds such as caffeine and taurine is higher compared to adults. This situation can lead to more intense and risky results in young people with the same amount of consumption. Research has shown that even a single energy drink consumption can push approximately 70% of children and 40% of adolescents above the safe caffeine limit of 3 mg/kg/day. Therefore, in some countries, the sale of energy drinks to those under 18 has been banned or restricted."
Exam success comes from regular sleep, balanced nutrition
Emphasizing that coffee and energy drinks can provide short-term alertness when consumed in the right amount and at the right time, Ekin Çevik concluded, "However, the foundation of exam success lies in regular sleep, balanced nutrition, and a healthy study plan. Building lasting habits instead of temporary solutions is the safest way for both mental and physical health."
