There’s a moment in the life of almost every student when the exam begins and your mind, right on cue, goes on vacation. It’s not that you didn’t study, or that you don’t know the answer. It’s that something in your body has flagged this exam as a real threat, and has triggered a survival response at the worst possible moment.
Let’s try to understand what’s happening inside us when we get overwhelmed before an exam, which solutions have experimental backing, and how to build yourself a system that can hold up under real pressure.
Remember that on Pensar es Gratis we only cite reliable data and sources that pass our content filter. At the end of each post there’s a practical guide on the topic if it makes sense for one to exist.
Why we get overwhelmed
Test anxiety has a specific neuroendocrine basis. The hypothalamic-pituitary-adrenal (HPA) axis activates in response to social evaluation situations and releases cortisol into the blood, a glucocorticoid that in turn triggers sympathetic nervous responses: rapid heartbeat, sweating, muscle tension [1]. A now-classic 1985 study measured cortisol excretion in elementary school children and found it was significantly higher on exam days than on regular school days, and that this increase was associated both with slightly above-average intelligence and with poor academic performance [2].
That cortisol isn’t bad in itself. The problem is its magnitude and timing. When sympathetic activation is high and sustained, the prefrontal cortex — the seat of working memory and complex reasoning — loses resources. Sian Beilock and Thomas Carr demonstrated this with expert performers put under pressure: the more automatic a skill is, the more it deteriorates if the pressure prompts you to consciously monitor it step by step, instead of letting it flow [3].
A systematic review with meta-analysis published in 2026, covering 35 studies and more than 13,000 medical students in twelve countries, found a prevalence of test anxiety of 49.8% [4]. By region, Southeast Asia and the Eastern Mediterranean showed the highest rates, though the differences weren’t statistically significant.
Mock exams work
A German study with 95 medical students measured heart rate variability during oral mock exams led by peers and led by professors. Both formats produced a significant reduction in parasympathetic activation, a sign of real physiological stress, and both reduced anxiety before real exams and increased perceived competence over the long term [6]. Professor-led mocks triggered a somewhat more intense sympathetic response; peer-led ones a more moderate but equally useful one. Worth noting: this data comes from a conference abstract not yet published as a full paper, so it should be treated as solid preliminary evidence, not the final word.
In nursing, a study with Iranian students who took a simulated clinical exam (OSCE) found a very marked drop in anxiety between before and after the mock exam, and the group that had practiced scored higher on the final exam than the control group [7]. The mechanism isn’t just “getting familiar with the format.” There’s something more interesting going on: the mock exam acts as a form of graded exposure. Your nervous system learns that the room, the clock, and the silence aren’t real threats, and along the way you discover something that can only be learned under real conditions: how your attention behaves under pressure, and what you need to adjust.
A team from Georgia State University trained capuchin monkeys on a video game with high- and low-pressure trials — same difficulty, different reward value — and found that monkeys with higher baseline cortisol levels performed worse precisely on the high-pressure trials, while repeated experience with that pressure improved their performance over time [8]. Choking isn’t a modern invention of school. It looks like an evolutionarily old mechanism, and like any old mechanism, it responds to training.
Time management
The basic rule is simple: time per question = minutes available ÷ number of questions. If you have 90 minutes for 100 questions, you have 54 seconds per question. That doesn’t mean each one should take exactly that long, but that if one takes more than double that average, you mark it and move on. The second pass, using 30-35% of the remaining time, goes to the marked ones.
You also need to factor in accumulated cognitive fatigue, independent of any given question’s difficulty. A study using administrative records from fifteen million Brazilian students who took the ENEM — the country’s largest university entrance exam — exploited a design detail: each student received the same questions, but in a different, randomly assigned order. This made it possible to isolate the pure effect of a question’s position within the day. The result: the probability of getting a question right dropped 18.7% when it appeared at the end of the exam instead of at the beginning, with the same objective difficulty [9]. It’s not that you know less by the end. It’s that sustaining mental effort for hours has a measurable cost.
That cost doesn’t hit everyone equally, and here’s some good news: a field experiment with 1,636 elementary school students in Lucknow, India, randomly assigned different groups to twenty minutes a day of cognitively demanding activity — math problems or games with no academic content — versus a control group. Those who practiced that sustained mental effort showed a 22% smaller drop in performance across long tests, and also improved their overall school results [10]. Endurance for sustaining mental effort doesn’t look like a fixed trait of intelligence. It’s trainable, just like physical endurance, and someone who has never done a long mock exam arrives at the real exam at a disadvantage even if they know exactly as much as their classmate.
Blanking out
Mental blanking on an exam — going blank on something you knew perfectly the night before — isn’t a memory failure. It’s an access failure. The information is stored. The problem is that acute stress compromises the executive control circuits of the prefrontal cortex, and without that control, retrieval becomes erratic. Beilock and Carr called this the fragility of expert performance: the more automatic a skill is, the more it can break down if pressure prompts you to consciously take it apart [3].
What does blanking do? You lose time, yes. But it also triggers a loop: you blank, you get distressed about having blanked, that distress consumes even more working memory, and the blank deepens.
The simplest intervention with the best experimental backing is writing about your worries right before the exam. Gerardo Ramirez and Sian Beilock published in Science two lab experiments and two field experiments showing that a brief expressive-writing assignment, ten minutes before an important exam, significantly improved scores. In one of the studies, the more anxious students who wrote about their worries went, on average, from a B- to a B+ [11]. The mechanism likely has to do with offloading working memory: if worries are taking up cognitive space, writing them down externalizes them and frees up that space for the exam. Worth noting: a later replication in a different university context didn’t find the same effect, so it’s not a universal guarantee.
Procrastination and anxiety
Academic procrastination and test anxiety are consistently linked in the literature — we’ve covered this in another post. A study with university students at Universidad de Congreso, in Mendoza, found a significant relationship between the two variables, with measurable negative consequences for academic performance [12].
A longitudinal study with adolescents at a high school in Changsha, China, measured procrastination and anxiety at two different points in the same semester, and found that procrastination at the first point predicted higher anxiety levels later on, while initial anxiety didn’t predict a later increase in procrastination [13]. Procrastinating doesn’t eliminate anxiety. It postpones it, and makes it bigger in the process.
What works isn’t abstract discipline. It’s reducing the friction of starting. Anxiety over a big task — “study all of unit 5” — is greater than anxiety over a small, concrete task — “read pages 47 to 52 and make an outline.” Realistic planning, with short blocks and scheduled breaks, reduces the anticipatory load before it has a chance to set in.
Practical guide
Before you prepare. Plan ahead, as we’ve covered in another post, but in small blocks. Avoid the trap of “studying the whole weekend.” A realistic plan includes breaks, 7-8 hours of sleep, and regular physical activity. Sleep isn’t optional: during sleep the brain consolidates what’s been learned, and sacrificing it to study more is a bad trade.
While preparing. Do mock exams under real conditions at least twice before the exam. Time yourself. Use the same type of answer sheet, the same silence, the same rule against checking notes. The more it resembles the real situation, the more useful the exposure will be.
The night before. Don’t study new material. Review outlines, headings, key words, try recalling the headings or main ideas out loud. Spend ten minutes writing down everything that’s worrying you about the exam. Don’t edit it. Don’t organize it. Just write it. Then close the notebook.
Exam day. Arrive with time to spare. If the exam is long, calculate your time per question before you start and write it on a piece of paper. Start with the questions you’re most confident about: every correct answer you mark reduces anxiety and frees up cognitive resources for the harder ones. (There’s also the option of starting with the hard ones first, if you want to use the “diffuse mode” approach.) If you blank, write down whatever you know about the question even if it’s not the full answer; sometimes the act of writing unblocks access to the information. And if the block persists, move on to the next question. There’s no medal for getting stuck on question 3 for fifteen minutes.
During the exam. Slow diaphragmatic breathing — inhale for 4 seconds, exhale for 6, no pauses — activates the parasympathetic system and lowers heart rate in under a minute. It’s not magic, it’s vagus nerve physiology. A brief mindfulness training, following the same logic of turning down mental background noise, showed a moderate-to-large effect on evaluative anxiety in a recent meta-analysis of 18 studies with more than 1,200 participants, though the authors themselves warn of possible publication bias in that literature [14].
The relationship between procrastination and anxiety is probably bidirectional in the long run, but the Chinese study suggests the loop breaks more easily from the action side than from the emotion side. In other words, starting to study reduces anxiety faster than trying to calm the anxiety in order to start. Action precedes mood, not the other way around.
References
[1] Hinds, J. A., & Sanchez, E. R. (2022). The Role of the Hypothalamus–Pituitary–Adrenal (HPA) Axis in Test-Induced Anxiety: Assessments, Physiological Responses, and Molecular Details. Stresses, 2(1), 146-155.
[2] Tennes, K., & Kreye, M. (1985). Children’s adrenocortical responses to classroom activities and tests in elementary school. Psychosomatic Medicine, 47(5), 451-460.
[3] Beilock, S. L., & Carr, T. H. (2001). On the fragility of skilled performance: What governs choking under pressure? Journal of Experimental Psychology: General, 130(4), 701-725.
[4] Omar, Y. M., Darwish, N. E., Elsaadany, M. A., Darwish, Y., & Eladawy, Y. (2026). Prevalence of test anxiety among medical students: a systematic review and meta-analysis. BMC Medical Education, 26, 1448.
[5] Infocop (May 27, 2026). Test anxiety: how to recognize it and how to manage it effectively. Consejo General de la Psicología de España.
[6] Gellisch, M., Brand-Saberi, B., & Schäfer, T. (2025). Targeted reduction of test anxiety: how peer- and lecturer-led simulations affect autonomic stress responses — HRV analyses compared. Annual Conference of the Society for Medical Education, 25gma149.
[7] Examining the Impact of MOCK OSCE on Test Anxiety and Clinical Performance of First-Term Nursing Students in the OSCE Exam (2024). Future of Medical Education Journal, 14(4). Lorestan University of Medical Sciences, Iran.
[8] Sosnowski, M. J., Benítez, M. E., & Brosnan, S. F. (2022). Endogenous cortisol correlates with performance under pressure on a working memory task in capuchin monkeys. Scientific Reports, 12, 953.
[9] Reyes, G. (2023). Cognitive Endurance, Talent Selection, and the Labor Market Returns to Human Capital. Working paper.
[10] Brown, C. L., Kaur, S., Kingdon, G., & Schofield, H. (2022). Cognitive Endurance as Human Capital. NBER Working Paper No. 30133.
[11] Ramirez, G., & Beilock, S. L. (2011). Writing about testing worries boosts exam performance in the classroom. Science, 331(6014), 211-213.
[12] Jofré Neila, M., Galván, D., & Riccio Cresto, B. (2024). Anxiety as a factor in procrastination and its consequences for academic performance in university students. PSIUC Revista de Psicología, (10). Universidad de Congreso, Mendoza, Argentina.
[13] Wang, Y. (2021). Academic procrastination and test anxiety: A cross-lagged panel analysis. Journal of Psychologists and Counsellors in Schools.
[14] Yılmazer, E., Hamamci, Z., & Türk, F. (2024). Effects of mindfulness on test anxiety: a meta-analysis. Frontiers in Psychology, 15, 1401467.
[15] Beilock, S. L. (2010). Choke: What the Secrets of the Brain Reveal About Getting It Right When You Have To. Free Press.