When providing your body with the proper amount of caffeine to boost your sports performance, don’t rely too much on a coffee or tea. It’s much better idea to use caffeine supplements.
The majority of studies on caffeine and sports performance have been carried out with pure caffeine in sports products, rather than by consuming tea or coffee, for good reason.
The exact amount of caffeine in your tea or coffee can vary significantly. For instance, one consumer test of espresso coffees purchased in a number of different shops showed that the exact caffeine content varied from 25mg to 214mg per cup.
Similarly, instant coffee can contain anything from 40-108mg of caffeine, while fresh tea can range from 20-50mg per cup. The fact is that if you use tea and coffee to consume your caffeine, there’s no way of being sure how much caffeine you’re consuming in reality.