The Schwinn Airdyne is an indoor exercise, or stationary, bike. While stationary bikes generally burn similar amounts of calories, the Airdyne offers optional upper-body exercises, which increase calories burned. Specific caloric figures are not available for the Airdyne, but you may wish to use an online calorie-burn calculator to estimate.
Stationary bikes gauge your level of effort in different ways, such as pedal rotations per minute, distance covered over time or watts of energy you generate by pedaling. The Schwinn Airdyne has its own calorie calculator and also measures rotations per minute and resistance level, the manufacturer explains.
On the Schwinn Airdyne, the pedal resistance increases the faster you pedal. This change approximates the effect of wind resistance for road biking. Measuring your speed alone isn't enough to estimate how many calories you're burning, because the resistance level controls how hard you must exert yourself to maintain speed.
The American Council on Exercise cites data indicating that stationary bike users burn 0.05 to 0.22 calories per minute per kilogram of body weight. The low end of this scale is for low energy outputs of 50 watts, while the high end is for 250 watts. The more you weigh or the faster you pedal, the more calories you'll burn. The Internet Fitness website calculates that a 160-pound person can burn 403 in 30 minutes of vigorous stationary cycling, for example.