The air bike is hard because of the resistance created by the fan. Most stationary bikes work with a motor or a magnetic resistance flywheel, whereas an air bike works with a fan. The harder you pedal, the more the resistance increases. Air bikes also typically have full-motion handles that give you a full-body workout when you use them with the pedals. The progressive resistance combined with your upper and lower body working in tandem can result in a brutal workout. However, you can also pedal slower, remove your arms from the handles, or rest your legs on the foot pegs to reduce the intensity.