Given the effectiveness of caffeine, many athletes, both beginners and professionals, regularly use or are tempted to use caffeine before training to boost their performance. The obvious question then is what caffeine doses should you consume to maximize your performance?
You could use the sledgehammer approach and consume very large caffeine doses to ensure you’re getting plenty to improve your performance. However, the problem is that massive doses of caffeine increase the risk of unwanted side effects. These can include fast or irregular heart beating, restlessness, anxiety, nausea and insomnia, none of which are wanted, regardless of how keen you’re to improve your performance.
This has led experts to examine what could be the minimum effective caffeine dose, this is the one that decreases the risk of any unwanted side effects but still improves performance. Studying the scientific literature on optimum caffeine intakes to boost performance, numerous studies have reported a variety of results.
Listed below are some key findings:
- Events lasting less than 30 minutes: caffeine doses of 6-9mg/kg appeared to produce major performance gains in trained subjects
- Events lasting 30-60 minutes: in runners, doses of 3mg/kg and 6mg/kg improved performance, but 9mg/kg had no effect. In cyclists, doses of 5, 9 and 13mg/kg all contributed to improved performance, and the magnitude of performance gain was the same for all doses. Another biking study produced performance benefits with doses of 2.1, 3.2 and 4.5mg/kg – the gains being highest at 3.2 and 4.5mg/kg.
- Events lasting over an hour: caffeine doses of 1-2mg/kg improved biking performance toward the end of two hours of biking to the same degree as 6mg/kg given at the start. Some scientists have suggested that this is because people may become more sensitive to caffeine as fatigue accumulates. Additionally, some studies have proven that large amounts of caffeine (9mg or more per kg) may actually be detrimental to performance in longer endurance events.
Taking into account these and other studies into different caffeine doses for sport performance, the balance of evidence has suggested that the optimum dose of caffeine depends on the exercise duration as follows:
- For short, high-intensity events lasting about 30 minutes, a caffeine dose of about 6-9mg/kg appears most effective.
- For events lasting about 60 minutes or longer, a caffeine dose of 3-6mg/kg is most effective.
The theory from these results is that you only use enough caffeine to boost your performance in a specific event, and therefore minimize the risk of any unwanted side effects.
It’s worth mentioning however that 6mg per kg of bodyweight equates to a dose of 420mg for a 70kg person, which is the same amount of caffeine that you’d get by consuming around 6 cups of instant coffee or 12 cups of freshly brewed tea.