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But fear not, there is a simple answer: intensity and the lack thereof. Cardio can be an effective supplement to your training. If the goal is to be lean, you must either do high-intensity cardio or low-intensity cardio as well as weight-lifting.
High-intensity cardio is similar to weightlifting, and the body responds to it in a similar way, by getting stronger or faster. This is a good thing, as improving performance makes you look better! Also, high-intensity cardio forces the body to adapt in a more favorable way than it does to medium pace cardio; to sprint faster your body needs to become stronger, and this leads to some muscle gain in the muscles being used, but more importantly it leads to no muscle loss! Examples of high-intensity cardio include sprinting, walking intervals on an inclined treadmill and circuit training with weights.
Low-intensity cardio is walking or riding a bike at a conversational pace, as you can carry on a conversation while doing it. The good thing about low-intensity cardio is that it too does not burn muscle, or at least a lot less than medium pace cardio does. This is because walking does not cause an adaptation to occur, your body does not need to change drastically to become more efficient at walking. It just needs energy, which it will get primarily from fat.
The final word on cardio is that it has its place as a supplement to your weight lifting and not as the only form of training you do - so if you’re gonna run,...