Are there negative side effects for using stationary bicycle for exercise?
I'd say that all the so-called "negative side effects" are more disadvantages compared to outdoor cycling. Indoor cycling is an excellent cardiovascular exercise, so please do not let the following dissuade you from doing it.
- It's boring. However, to make things more interesting and depending on your setup, you can use an online training program like Zwift, TrainerRoad, or SufferFest.
- Since there's no wind to cool you down, you may overheat more easily. That can be solved by riding with a fan in front of you.
- I personally get more saddle sores when I do indoor training than when I ride outside. I think it's because I tend not to get out of the saddle as much when I'm doing indoor training.
- Cycling (both indoor and outdoor) is not fully weight bearing. If you are looking for something to prevent osteoporosis, you'll need to add something else like walking to your program.
- Oh, I almost forgot about the fact that you do not gain any bike handling skills from indoor training. If you aren't interested in riding outdoors, it's obviously not a problem.