Exercise should include nonstop activity performed for 30 or more minutes in order to keep the heart rate up. In other words, it should be done in a(n) ________ way.

【参考答案】

答案：cardiovascular解释：根据句子的描述，这种运动应该是持续的，时间至少为30分钟，目的是保持心率的提升。......

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