At first, you taste it from the very tip of your tongue…

« Yuck! It tastes so bad compared to hot chocolate! It’s not even sweet! »

The second time, you order a « French Vanilla », and you now think you’re such an accomplished adult.

Then come the experimentations with one less sugar packet. One less milkette.

You’re slowly realizing that what you initially found utterly bitter and way too hot has now become the very reason you enjoy your morning routine. You even caught yourself blowing a morning kiss to the first rays of sunshine last week!

Before you jump to the next step (AKA becoming best buddy with your corner barista), I suggest learning about caffeine safety. And as usual, I added a little sports angle to « pumpkin spice » it up! (too much, okay)

Daily consumption of caffeine

Caffeine is overall very safe. You must not, however, exceed a certain dosage. Also, there are strategic moments when its consumption is recommended if you want to get the most out of it without any adverse effects.

Caffeine in everyday drinks

Caffeine is found in the following drinks :

  • 1 can cola – 34 mg
  • 1 can diet cola – 45 mg
  • Black tea – 47 mg
  • Single espresso (30 mL) – 75 mg
  • Energy drink (250 mL) – 80 mg
  • Home-brewed coffee (250 mL) – 95 mg
  • Double espresso (60 mL) – 150 mg
  • Energy drink (473 mL) – 160 mg
  • « Grande » size coffee (473 mL) – 330 mg
  • « Venti » sized coffee (591 mL) – 415 mg

Recommended dosage

According to Health Canada, the Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA), consumption of caffeine is safe up to 400 mg per day for healthy adults and up to 300 mg per day during pregnancy.

Knowing that a home-brewed coffee contains 95 mg of caffeine on average, we can already answer the question in the title of this article! « Too much coffee » would be more than 4 cups daily.

In children, Health Canada recommends the following dosage :

  • 4–6 years old ➞ 45 mg, about 1x 355 mL can of cola
  • 7–9 years old ➞ 5 mg, about 1.5x 355 mL can of cola
  • 10–12 years old ➞ 85 mg, about 2x 355 mL can of cola

Adverse effects

Higher doses (> 400-500 mg) of caffeine are linked to an increase in anxiety, especially in non-habitual caffeine consumers.

Smaller doses (~100 mg) can increase time before falling asleep, but only when caffeine is consumed close to bedtime. And by « close to bedtime », I mean immediately before going to sleep, according to the study in question. I mean, why not drink a cup of coffee right before bed right? ¯\_(ツ)_/¯

Sports nutrition has joined the chat

In my latest blog, we covered all sources of caffeine available as supplements. Whether you consume it as a sports gel, a preworkout or an effervescent table, caffeine is quite easy to get when you know where to look. It can be found in small amounts (e.g. 25 mg in s « GU Espresso Love » sports gel) or in large amounts (e.g. 200 mg in « Wake Ups » tablets).

As a supplement, dosage matters more than the product you get it from. Across dozens of studies, a caffeine intake before an effort has consistently been shown to improve endurance by 2-4%. Aerobic endurance is particularly central in sports such as running and cycling. 2-4% may seem rather small, but you have to consider that at the highest levels of performance, it takes very little to separate the winner from the others. For example, in the men’s individual road race during the 2016 Rio Summer Olympic Games, the difference between the top three medalists was less than 0.01%. 2-4% suddenly appears much bigger in retrospect!


The protocol most studied for supplementing with caffeine is to consume 3-6 mg/kg body mass 60 minutes before an effort. A similar dose taken during and towards the end of an endurance event is also associated with a decrease in perceived exertion, making the effort feel easier.

An exception to the 60-minute window is when caffeine is consumed in the form of a gum. Caffeine is absorbed quicker that way, allowing athletes to have it closer to the effort.


To maximize the improvement on performance and minimize adverse effects that may come with a larger dose of caffeine, it is recommended that athletes try to test and find the lowest dosage for which they notice an improvement on their performance.

In fact, improvements can be seen at doses as low as 2 mg/kg in non-habitual caffeine users.

Doses larger than 9 mg/kg should be consumed cautiously, as they are associated with a greater risk of adverse effects : jitters, gastrointestinal issues, trouble focusing, headaches, hindered sleep quality, tachycardia, altered sports performance, etc.

In short, recommendations point to testing the lowest dosage for which a noticeable improvement to performance is seen. A good starting point is 2 mg/kg, increasing slowly up to 6 and for some even 9 mg/kg.

The question on everyone’s lips : does caffeine dehydrate?

What science tells us ➞ caffeine is a diuretic, meaning it decreases fluid reabsorption from the kidneys, resulting in an increased urine output.

What science also tells us ➞ contrary to popular belief, caffeine consumption has little to no impact on hydration status or thermoregulation and does not put us at risk of dehydration. The same findings are seen in warm environments.

In the end, drinking a caffeinated beverage implies having more liquid going in that what we lose from urine output. Net positive, we like that.

Final words

You now know the answer to our initial question : « How much coffee is too much coffee? ». Will you drink past that number? Your call! (*but you can wait until after your 4th coffee to make such a big decision, no stress)



Bagchi, D. (Ed.). (2017). Sustained Energy for Enhanced Human Functions and Activity. Academic press.

Burke, L. M. (2008). Caffeine and sports performance. Applied physiology, nutrition, and metabolism33(6), 1319-1334.

Guest, N. S., VanDusseldorp, T. A., Nelson, M. T., Grgic, J., Schoenfeld, B. J., Jenkins, N. D., … & Campbell, B. I. (2021). International society of sports nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition18(1), 1-37.

La Vieille, S., Gillespie, Z., Bonvalot, Y., Benkhedda, K., Grinberg, N., Rotstein, J., … & Krahn, A. D. (2021). Caffeinated energy drinks in the Canadian context: health risk assessment with a focus on cardiovascular effects. Applied Physiology, Nutrition, and Metabolism46(9), 1019-1028.

Landolt, H. P., Dijk, D. J., Gaus, S. E., & Borbély, A. A. (1995). Caffeine reduces low-frequency delta activity in the human sleep EEG. Neuropsychopharmacology12(3), 229-238.

NDA, E. S. P. (2015). Scientific opinion on the safety of caffeine. Efsa Journal13(5), 4102.

Rotstein, J., Barber, J., Strowbridge, C., Hayward, S., Huang, R., & Godefroy, S. B. (2013). Energy drinks: an assessment of the potential health risks in the Canadian context. International Food Risk Analysis Journal3.

Santé Canada. Caféine : Foire aux questions – Information à l’intention des parents sur la caféine dans les boissons énergisantes. Ressource consultée en ligne le 21 mars 2022.


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