In this case the first person is probably complaining that they don't get enough exercise or need to get fit. The second person is replying with your sentence which is a conditional sentence. (2nd Conditional) In this case if you do one thing the second will happen. For more on conditionals I have some videos on youtube. https://www.youtube.com/watch?v=rkEiw_H1fp8&index=10&list=PLIcNItpI5Y7CByenUL965_JYRKIeFp0Ch Hope this helps Bob

"Get more exercise" is a comparative statement meaning that if you rode your bike to work you would get more physical activity than using some sort of automotive transportation.

For me it sounds the same as to say "If you rode your bicycle to work, you would GO INFO SPORT MORE.

In this case, the word "exercise" is being used as a noun instead of a verb. Therefore if you rode your bike to work instead of driving, you would "get more exercise."