Your instructor will guide you through workout phases. Warm-up, sprints, climbs, cool-downs, etc. You control resistance on your bike to make the pedaling as easy or difficult as you choose. Constant adjustment is normal. All you'll need is workout clothes, a towel (to wipe your face) and a water bottle. (Indoor bike have toe clips so you can wear tennis shoes)

Indoor Bike classes can be a great way to get in a vigorous but low impact workout in a fun environment.