Caffeine is a naturally occurring alkaloid found in coffee, tea, cocoa and guarana, among other sources, and is one of the best-studied active substances in sport. It acts on the central nervous system and can influence subjective alertness and the ability to concentrate.
The effect of caffeine usually sets in after about 30 to 60 minutes and, depending on individual metabolism, lasts several hours. How sensitively someone reacts to caffeine differs greatly and depends on habituation, genetics and time of day, among other things.
Relevance for nutrition and sport
In sports science, caffeine is considered one of the best-supported substances in connection with endurance performance and perceived exertion, especially at moderate intake before training. Commonly cited amounts are around 3 mg per kilogram of body weight as a rough guide, while the manufacturer's instructions on the product are what count.
In sensitive people, caffeine can cause palpitations, nervousness or sleep problems, so taking it later in the day can impair sleep. People with cardiovascular disease, during pregnancy or when taking certain medications should have their caffeine consumption checked by a doctor first. The guide pre-workout boosters tells you more about caffeinated products before training.
