What is good cardio exercise?!

Question: I don't know if the rowing machine is a good cardio machine?

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Answers: I don't know if the rowing machine is a good cardio machine?

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Anything that keeps your heart rate up, really. A rowing machine would do the trick, but would also strengthen muscle at the same time.
Running, cycling, and stair activities or machines would work really well too.

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jump roping.

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