Originally Posted by
terrymorse
The most important reason to increase your cadence is to spare your legs from muscle fatigue. On a long and hard ride, it's always your leg muscles that get tired. Heart and lungs can go on forever.
As an example, consider weight lifting. 10 reps at 100 pounds is more exhausting than 20 reps at 50 pounds.
Well your muscles fatigue because your lungs can't supply them with enough oxygen. But yes minimizing that fatigue is the name of the game.