Coffee for studying in exam season: the night before, exam morning and the exam room

Exam season changes how coffee fits your day. A late cup the night before can cost you sleep. On exam morning, a new or extra drink can bring effects you do not want. And many exams limit what you can eat and drink in the room. This guide covers those three moments. It is written for adults.

The short answer: keep your coffee boring in exam season

For everyday study sessions, our guide to the desk coffee ritual covers how coffee fits a study block. Exam season needs a simpler plan.

1. The night before. Have your last cup early and protect your sleep.
2. Exam morning. Have your usual cup at your usual time, with nothing new and nothing extra.
3. The exam room. Finish your coffee before you go in. Many exams limit food and drink in the room.

The night before an exam: an early last cup, and sleep over a late cram

Caffeine stays in your body for hours. Its half-life, the time your body takes to clear half of it, is usually three to seven hours [1]. People also differ a lot in how fast they clear it [2]. So a cup in the late afternoon can still be working at bedtime.

That matters for sleep. A 2023 review pooled 24 studies and found that caffeine cut total sleep time by 45 minutes on average [3]. The size of the dose matters too. In one study, a single 400 mg dose disturbed sleep even when it was taken six hours before bed [4]. That is as much caffeine as the European Food Safety Authority's figure for a whole day. The same authority says a single dose of 100 mg may affect sleep in some adults, particularly close to bedtime [5].

The studies do not all agree on a small cup late in the day. A 2025 trial in 23 young men who already drank caffeine found no significant effect on sleep from 100 mg taken four hours before bed. A 400 mg dose did affect sleep when it was taken within 12 hours of bed [6].

So no single cut-off hour suits everyone. The 2023 review worked out that a cup of coffee needs to come at least 8.8 hours before bed to avoid losing sleep. It assumed 107 mg of caffeine in a 250 ml cup [3]. If you go to bed at 11 pm, that is a little after 2 pm. In exam week, when sleep counts most, the review's earlier cut-off is the careful choice.

Sleep is also why a late cram is a poor trade. In one experiment, 44 college students took a critical-thinking test after either about 8 hours of sleep or 24 hours awake. The students who stayed awake did worse, yet rated their own performance higher [7].

One study adds a caveat. Researchers tracked the sleep of 88 college students through a chemistry course. Sleep over the week and the month before a test was linked with test scores. Sleep on the single night before a test was not [8]. So one good night is not a fix. The night before is the night not to lose sleep, and steady sleep through the weeks of revision is what that study linked with scores.

So the plan for the night before is to have your last cup early, skip the late one, and go to bed at your usual time.

Exam morning: your usual cup at your usual time

Exam morning is not the day to change your coffee. Two sets of findings point the same way.

An extra or unfamiliar dose brings more of what you do not want. In a study of 379 adults, people who drank caffeine regularly had a smaller rise in anxiety after a dose than people who rarely drank it. The authors say regular use builds tolerance to that effect [9]. The US Food and Drug Administration lists jitters, a faster heart rate, trouble sleeping and an upset stomach among the signs of too much caffeine. It also says how much is too much varies from person to person [2].

Skipping your usual cup has a cost too. In the same study, regular drinkers who were given a placebo instead of caffeine felt less alert and reported more headache [9]. A 2004 review of 66 studies found that stopping caffeine can bring headache, tiredness and trouble concentrating. These usually start 12 to 24 hours after the last dose. They showed up even in people who stopped as little as 100 mg a day [10].

So the plan is your usual cup, at your usual time, with nothing new and nothing extra. No study has tested this exact advice on exam day. It follows from the findings above. Do not add a second cup, a stronger brew or an energy drink you have never had. If you do not usually drink coffee, exam morning is not the day to start.

If you want your usual cup to be a settled habit by exam day, start it early in revision. Our guide to building a morning coffee routine that sticks shows how.

The exam room: finish your cup before you go in

Many exams limit food and drink in the room. The rules differ, so check your own exam's rules a few days ahead. Here are four examples.

• GRE, run by ETS. The 2026-27 bulletin says: "Food, beverages, tobacco and e-cigarettes are not allowed in the testing room." [11]
• Institute of Internal Auditors exams at Pearson VUE centres. "No food or drink is allowed in the testing room." [12]
• University of Westminster. Water in a clear, unlabelled plastic bottle and unwrapped sweets are allowed. Other food and drink is not, unless agreed as a reasonable adjustment [13].
• University of Greenwich. Water, a soft drink and unwrapped sweets or fruit are allowed. The drink must be in a clear bottle, not a can [14].

None of these four names coffee as allowed in the room. Some make exceptions for approved medical needs, so ask your exam body if that applies to you. The plan is to finish your coffee before you go in, and take in only what your exam allows.

Where CafeBank fits: the SFE Maca & Guarana Coffee 10g

The advice above comes down to one idea. On exam morning, have nothing new. The CafeBank SFE Maca & Guarana Coffee 10g makes that easy, because every SFE Maca & Guarana Coffee 10g stick is the same sealed 10 g serving. If it is your cup through revision, it can be the same cup on exam morning.

• In the stick. A 3-in-1 instant coffee made with single-origin Arabica, plus maca and guarana extracted by supercritical CO2 (SFE), with no ethanol or hexane in the process. For what SFE means, read what SFE means in functional coffee.
• Directions. One stick in 150 to 200 ml of hot water. Stir until it dissolves.
• Allergens. Contains milk, from the dairy creamer. Not suitable for individuals with milk allergy or lactose intolerance.
• Caffeine. For where the caffeine in a maca and guarana coffee comes from, read does maca have caffeine?

Contains caffeine. Not recommended for children or pregnant women.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Try the SFE Maca & Guarana Coffee 10g early in revision, so it is already your usual cup by exam morning.

Shop the CafeBank SFE Maca & Guarana Coffee 10g

A note on caffeine

For most adults, the US Food and Drug Administration cites 400 mg of caffeine a day as an amount not generally associated with negative effects [2]. The European Food Safety Authority says single doses up to 200 mg, and up to 400 mg a day, raise no safety concerns for healthy adults, except pregnant women [5]. These figures cover caffeine from all sources combined. They are not limits for any one product.

Pregnant or breastfeeding, under 18, living with a heart rhythm disorder, poorly controlled high blood pressure, an overactive thyroid, or a stomach or duodenal ulcer, or taking prescription stimulants or MAO inhibitors: talk to your own clinician before adding any concentrated caffeine source, from any plant. These are the populations named in the European Medicines Agency's herbal monograph on guarana seed and in the food-safety authorities' caffeine opinions.

The CafeBank SFE Maca & Guarana Coffee 10g contains caffeine and is not recommended for children or pregnant women. This article is written for adults.

Coffee in exam season: common questions

Is a late coffee a good idea the night before an exam?

A late cup can cost you sleep. A 2023 review of 24 studies found caffeine cut total sleep time by 45 minutes on average. Have your last cup early and keep your usual bedtime.

Should I drink coffee before an exam?

If you are an adult who already drinks coffee, have your usual cup at your usual time, with nothing new and nothing extra. If you do not usually drink coffee, exam morning is not the day to start.

Can I take coffee into the exam room?

Often not. Many exams limit food and drink in the room. The GRE does not allow food or beverages in the testing room, and neither does the Institute of Internal Auditors at Pearson VUE centres. Check your own exam's rules and finish your coffee before you go in.

How long does caffeine stay in your body?

Caffeine's half-life, the time your body takes to clear half of it, is usually three to seven hours. People differ a lot in how fast they clear it, so an afternoon cup can still be working at bedtime.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This article is general information about food ingredients, not medical advice. If you are pregnant or nursing, take prescription medication, or have a heart, thyroid or anxiety condition, talk to your doctor before adding a caffeinated botanical product to your routine.

References

1. Puri BK, Heard CR, Monro JA. (2020). Is there a sex difference in adult salivary clearance of caffeine (1,3,7-trimethylpurine-2,6-dione)? J Oral Biol Craniofac Res. 10(2):20-22. DOI: 10.1016/j.jobcr.2020.01.010. PMID: 32071850.
2. U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine is Too Much? Consumer Update, content current as of 08/28/2024. Read 8 November 2026. https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much
3. Gardiner C, Weakley J, Burke LM, Roach GD, Sargent C, Maniar N, Townshend A, Halson SL. (2023). The effect of caffeine on subsequent sleep: A systematic review and meta-analysis. Sleep Med Rev. 69:101764. DOI: 10.1016/j.smrv.2023.101764. PMID: 36870101.
4. Drake C, Roehrs T, Shambroom J, Roth T. (2013). Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. 9(11):1195-1200. DOI: 10.5664/jcsm.3170. PMID: 24235903.
5. European Food Safety Authority. Caffeine, topic page. Read 8 November 2026. https://www.efsa.europa.eu/en/topics/topic/caffeine
6. Gardiner CL, Weakley J, Burke LM, Fernandez F, Johnston RD, Leota J, Russell S, Munteanu G, Townshend A, Halson SL. (2025). Dose and timing effects of caffeine on subsequent sleep: a randomized clinical crossover trial. Sleep. 48(4). DOI: 10.1093/sleep/zsae230. PMID: 39377163.
7. Pilcher JJ, Walters AS. (1997). How sleep deprivation affects psychological variables related to college students' cognitive performance. J Am Coll Health. 46(3):121-126. DOI: 10.1080/07448489709595597. PMID: 9394089.
8. Okano K, Kaczmarzyk JR, Dave N, Gabrieli JDE, Grossman JC. (2019). Sleep quality, duration, and consistency are associated with better academic performance in college students. NPJ Sci Learn. 4:16. DOI: 10.1038/s41539-019-0055-z. PMID: 31583118.
9. Rogers PJ, Hohoff C, Heatherley SV, Mullings EL, Maxfield PJ, Evershed RP, Deckert J, Nutt DJ. (2010). Association of the anxiogenic and alerting effects of caffeine with ADORA2A and ADORA1 polymorphisms and habitual level of caffeine consumption. Neuropsychopharmacology. 35(9):1973-1983. DOI: 10.1038/npp.2010.71. PMID: 20520601.
10. Juliano LM, Griffiths RR. (2004). A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology (Berl). 176(1):1-29. DOI: 10.1007/s00213-004-2000-x. PMID: 15448977.
11. ETS. GRE Information Bulletin, July 1, 2026 through June 30, 2027, page 10. Read 8 November 2026. https://www.ets.org/pdfs/gre/gre-info-bulletin.pdf
12. The Institute of Internal Auditors. Checking in at the Pearson VUE testing center. Read 8 November 2026. https://www.theiia.org/en/content/certifications/checking-in-at-the-pearson-vue-testing-center/
13. University of Westminster. Exam and assessment FAQs. Read 8 November 2026. https://www.westminster.ac.uk/current-students/studies/exams-and-coursework/exam-and-assessment-faqs
14. University of Greenwich. Exams FAQs. Read 8 November 2026. https://www.gre.ac.uk/student-services/exams/faqs