Exercise bikes are very popular. You can find them not only in every professional gym in the country, but in many home gyms as well. There are programmable upright bikes and recumbent exercise bikes as well. Some folks with back trouble prefer recumbent cycles. If you are considering getting an exercise bike for yourself, it is probably best to try out a few at a local gym first.
In the warmer weather like we have now, I generally prefer to ride a bicycle outdoors and only use an exercise bike as a warmup at a gym. However, during the cold winter weather when it is icy outside it can be safer to rely on an indoor bike unless you can head out to areas away from traffic. Many auto drivers aren’t as used to looking for bicyclists on the road in the middle of winter.