Next time you do cardio get on an;

Elliptical trainers tread motion is similar to that of a stair climber machine but instead of stepping up and down the elliptical trainer steps in an elliptical motion. This elliptical motion produces less impact on the knee and hip joints. This low impact feature is one of the main benefits of the trainer.
The full body exercise features and the weight bearing design are what allow you to burn more calories than you would on an exercise bike or treadmill. Although you can get some strength building benefit from the load bearing design of an elliptical trainer, it is primarily made for cardiovascular exercise. You can really get quite a cardiovascular workout with one of these machines. Some people compare the workout to walking through sand or snow.
Ultimately, working all of these different muscle groups will give you a toner, fitter body. The workout is more even. You will also lose weight, tighten your muscles, and improve the health of your cardiovascular system.