Caffeine and sport, everything you need to know
What is caffeine?
Caffeine is a natural alkaloid found in coffee beans and tea leaves, although there are other natural sources such as kola nuts, yerba mate, guarana berries and Yaupon holly.
What are the effects of caffeine?
Caffeine, alerts and attention
Based on scientific evidence, the European Food Safety Authority (EFSA) has confirmed that caffeine in doses of at least 75 mg increases alertness and attention. This means that it increases the speed of reaction times in healthy people.
When do you 'feel' the effects of caffeine?
Caffeine is quickly absorbed via the gastrointestinal tract, reaching peak plasma concentrations approximately 30 to 60 minutes after ingestion. It then remains relatively constant for a number of hours.
How does caffeine help physical performance?
Increased endurance
Several studies in physically active people show that caffeine doses between 3 and 9 mg/kg can increase endurance performance.
These effects are provided by: maximal pulmonary ventilation, elevation in VO₂-max (maximal amount of oxygen in the blood for metabolic activities), and muscle oxygen saturation during exercise.
Running performance
Scientific evidence shows two main areas where caffeine supports physical performance:
- Vertical jumping and running performance: review of over 34 sport experiments measuring physical and physiological variables during sessions, with an average caffeine intake dose of 4.5 mg/kg, showed that vertical jumping and running performance were positive in both overall distance covered, agility and accuracy.
On the other hand, caffeine intake did not affect the level of perceived effort during exercise, and the dose was taken between 10 and 70 minutes before the onset of exercise.
- As a fuel source: Other recent studies also show that caffeine intake increases the rates of fatty acid oxidation in both male and female healthy individuals, being a primary source of fuel before carbohydrates.
The effects of caffeine on athletes
A pre-exercise intake of a moderate dose of caffeine has been shown to be effective in increasing several physical performance variables in team sport athletes during specific events and matches.
Caffeine has been shown to be effective in improving performance in different kinds of sporting activity: endurance, high-intensity, team sports, power-strength activities and even sub-maximal exercise, because it reduces fatigue and increases muscle strength at the end of exhaustive exercise.
It is also effective in increasing alertness, response time, motor learning and recent memory.
Caffeine has not been included on World Anti-Doping Agency's list of banned substances since 2004.
Are there any contraindications to caffeine?
Caffeine, in normal doses, has mild side effects, such as gastrointestinal discomfort, anxiety, headache, tremor, restlessness, nervousness, psychomotor agitation, difficulty concentrating, insomnia, irritability, dependence, tachycardia and hypertension.
There are warnings about its use, but no contraindications.
Pregnant women should carefully reduce their caffeine intake to less than 300 milligrams a day (less than 445 ml of coffee, or 15 ounces), and people under 18 years of age are not recommended, and those with cardiovascular or neurological disorders should ask their doctor before taking caffeine.
Benefits of Caffeine, fatty acid oxidation
Several studies have evaluated the benefits of caffeine during exercise.
Study in Spanish Universities
A study in 2021 by Ramirez et al, performed at the University of Granada and King Juan Carlos University, evaluated the effects of caffeine intake on fatty acid oxidation taking into account diurnal variation during sports practice.
For this purpose, healthy, active subjects underwent a graded cycling test four times at seven-day periods, with one group taking caffeine (3 mg/kg) and the other placebo (no caffeine), at 8 am and 5 pm.
Maximal fat oxidation rate (FFR) and maximal oxygen consumption were measured, and the exercise intensity induced by the FFR was calculated.
Study results
The results showed that caffeine compared to placebo increased fat oxidation by 10.7% in the morning, and by 29.0% in the afternoon.
These results suggest that:
Afternoon fat oxidation by caffeine.
The combination of caffeine intake and moderate-intensity exercise in the afternoon provides the best scenario for people looking to increase whole-body fat oxidation during aerobic exercise.
Ergogenic support from caffeine in the morning
Caffeine intake in the morning could be used by athletes as an ergogenic support to help them avoid morning-induced reduction in muscle performance.
What is the maximum amount of caffeine to be taken daily?
According to the Spanish Society of Sports Medicine, single caffeine doses of up to 200 mg and daily intakes of up to 400 mg, distributed throughout the day, do not raise safety problems for healthy adults.
There is also no problem with taking caffeine (at the above doses) less than 2 hours before the onset of intense exercise.
