Caffeine is a natural stimulant, which can be found in plant based foods and drinks, like coffee, tea, chocolate, cola and guarana. Caffeine typically boosts our alertness and energy levels, though it affects everyone differently, with some people being very sensitive to it, whilst others notice very few effects. Caffeine typically boosts our alertness and energy levels.
Caffeine in its raw form is a white powder that is bitter to taste, the chemical name is 1,3,7 trimethylxanthine. It typically takes about 45 minutes to be absorbed into the bloodstream, but you can notice the effects from 15 minutes. Caffeine from drinks is quickly absorbed, whereas that from solid foods can be slower to absorb. That means drinking your morning espresso on an empty stomach will give you a quick caffeine hit then after breakfast.
Caffeine is broken down mainly by the liver and can remain in the bloodstream for 1.5 to 9.5 hours.
The amount of caffeine per coffee can vary widely depending on roast profile, brew type and variety of coffee, but it is widely accepted that for 400mg of caffeine per day is a recommended daily maximum for healthy adults (200mg for pregnant women), 400mg being equivalent to about four mugs of coffee.
A typical espresso coffee coffee will have about 50-65mg (per ounce/28g) and a normal cup of filter coffee about 12-14mg of caffeine (per ounce/28g), but your normal filter coffee might be 150-200ml, meaning the total amount of caffeine per mug can be 100mg.
Arabica vs Robusta Coffee
Robusta coffee beans have on average 83% more caffeine than arabica beans, so making coffee with these beans will produce a cup of coffee with 83% more caffeine. So a robusta espresso could have 120mg, and a mug of robusta filter could be 200mg of caffeine.
Coffee and Exercise
Cyclists are particularly fond of strong coffee due to the performancing enhancing boost it gives, particularly for endurance. Caffeine was actually placed on the World Anti-Doping Agency’s (WADA) banned list in 1984 and remained there until 2004 when it was removed.
Caffeine is known to bind with the receptors for adenosine. Adenosine promotes muscle relaxation, sleepiness, and blocks dopamine. This is the cause of many of caffeine’s more typical effects such as increased heart rate, blood pressure, alertness, and also is one of the things that helps with performance enhancement.
How much do I need to help with exercise?
In short quite a lot! When studied by sports scientists, the recommended amount is 3-6mg per kg of body weight. So for an average male of 75kg that would be 225-400mg of caffeine - so at least 2-4 mugs of coffee. That said, if you are a regular coffee drinker you will build up a tolerance and therefore need more.