To maximise your cycling comfort and efficiency, it helps to ride with the right cadence. Cadence is your pedaling speed as measured in revolutions per minute (rpm), how many times you turn the pedals around in a full circle each minute.

Each time you push on your pedals, your muscular system kicks in to produce power, and your cardiovascular system fires up to deliver oxygen and fuel to your muscles and to clear metabolic waste, like lactic acid, that you produce as you ride. The cadence you select should allow you to balance both of these systems without either one burning out before the ride is done.
What’s the sweet spot? For most riders it’s somewhere in the 80 to 100 rpm range, the place where you can pedal fast, but in control, while still applying a moderate, sustainable amount of pressure on the pedals. (Obviously, your cadence will drop when going uphill, which is fine.) There are some bike computers that will tell you your cadence, but you can also simply count. To count your cadence, use a stopwatch to count the number of times your leg pushes down on the pedal for 30 seconds and multiply by 2. Or if that is too difficult to do while you ride, just count for 10 seconds and multiply by 6. Once you get the hang of what various cadences feel like, it will become automatic to use your shifting to keep your cadence in a quick and comfortable range.

If your cadence is low, say below 80, try to increase it. How high depends on your physiology. The riders who benefit from a higher-end cadence are generally lighter riders, women, master (older) cyclists, and others whose aerobic capacity tends to be greater than their muscle power. As a general rule when you’re starting out, if your legs are giving out before your lungs, increase your cadence. If you’re gasping for breath but your legs are fine, lower it. Practice will help you improve your cadence and find the right rpm for you.