Some machines tend to be very similar in the motion they offer, such as the recumbent bike and the upright bike. Though you would be switching machines, the movement and the muscles used will be similar to the previous machine. As a result, you still wouldn’t be burning as many calories as you could be.
The best machines to switch to are those that are entirely different. Switching from a treadmill to a rower would be a perfect example of a good switch. The two motions are very different and as a result work different muscles causing an increase in your body’s calorie loss. Because the rower is so unique, it tends to be a great machine to switch to.
If you are really looking to increase the amount of calories you burn during a workout, it is best to actually skip the cardio machines and go right to strength training. Strength training isn’t always thought of as a fat-loss method, but I can assure you it most definitely is. It does this by increasing your basal metabolism (your metabolism at rest), turning you into a fat-burning machine even when you aren’t working out.
The overall theme that should be realized by those who are attempting to get a leaner body is that change is a must. You need to change what you are doing and also progress your workouts effectively so that your body does not become stale.
Your body will continue to burn calories and change as long as you continue to keep things challenging for it.