But fat as fuel is not as readily available to the muscles as carbohydrates. Fat must be used with carbohydrates to fuel working muscles. So anything that can make the thousands of calories of stored fat more available for use by the muscles will conserve the limited carbohydrate storage that much longer, prolonging the workout, often at a higher intensity. That is where caffeine comes in. About an hour after a couple of cups of strong coffee, muscles begin to use fat from the blood more efficiently, reducing the need, at least temporarily, for carbohydrates.
Caffeine has other benefits.
Mentally it increases alertness, makes the exercise seem easier than it is. The bottom line for caffeine is that a cup or two of strong coffee, three cans of soft drinks with caffeine or three cups of strong tea, can improve the performance of athletes working out at near maximal effort. Caffeine has no effect on sprint events. 1999, The Times-Picayune. Used with permission.