Coffee and Working Out: Investigating 4 Myths

My workout

Published on 30 January 2018
by Philippe Morvan
Having a coffee before/during your workout dehydrates you? FALSE

In moderation (3 cups of coffee or less a day), caffeine has a rather negligible diuretic effect. Research has shown that drinking a glass of water and drinking a cup of coffee produce a similar amount of urine. What’s more, coffee may even help maintain good hydration levels. However, this is not the case for alcoholic beverages, which do cause dehydration.

Caffeine boosts athletic performance? TRUE (partly)

Caffeine can improve athletic performance in many disciplines, especially in long-distance aerobic endurance exercises (marathon, half-marathon). In addition to stimulating the nervous system, caffeine reduces perceived exertion and delays fatigue, allowing you to exercise for longer. On average, a runner who consumes caffeine (around 2–3 cups of filter coffee) before or during a run can improve their performance by about 5%. It should be noted, however, that these effects aren’t the same for every athlete and that frequent coffee drinkers will experience less of an effect than occasional ones. Furthermore, since caffeine can cause some intestinal discomfort, it’s better to test its effects during training, before trying it out during a competition.

Excessive caffeine consumption may harm your health? TRUE

Excessive caffeine consumption can have several adverse side effects that could pose a danger to your health. These include heart palpitations, increased blood pressure, irritability, anxiety, tremors, insomnia, and intestinal problems. As with every good thing, it’s important to be reasonable and consume in moderation. Health Canada recommends no more than three 237 ml cups per day for healthy adults and two 237 ml cups per day for pregnant or nursing women.

Drinking coffee helps you lose weight? FALSE

Many studies have indeed shown that caffeine promotes lipolysis, i.e. the burning of lipid (fat) reserves, while simultaneously maintaining glycogen (sugar) levels during physical exertion. However, the effects of coffee or caffeine supplements on body fat or weight loss appear negligible. In fact, certain researchers have found that excessive caffeine consumption (6 cups a day) may even cause weight gain. What’s more, adding flavouring agents (sugars, artificial flavours, syrup, etc.) significantly increases calorie counts and promotes weight gain.



Philippe Morvan
Kinesiologist, training supervisor