I love exercise bikes or real ones, though I tend to get more exercise on my stationary bike. If you have never tried one, then you should. If you have access to a gym, try a spin class. Lots of calories will be burned and it is a lot of fun.
Even if you can’t make it to a spin class, you can still create your own circuit workout. Simply hop on an exercise bike, warm up for about five minutes or so. From there, increase resistance and speed... do this in increments, 8 seconds of pedaling as fast as you can, with 10/12 seconds of less frequent pedaling. Continue on this path for 5 mins or so, then rotate that with pedaling as fast as you can for 1 - 2 minutes, then slowing back down for 2 mins. Keep rotating so you keep your body guessing. Once your workout is complete (40 or so mins later), enjoy a 5 minute cool down on the exercise bike.
Congrats you just burned a LOT of calories!!!!