The Best Cardio Bodyweight Exercises You Can Do Right in Your Living Room

The higher the knees the higher the heart rate. "High knees are perfect for boosting cardiovascular endurance and activating the lower body, especially the quads and hip flexors," Cooper says. Here's how to do high knees:

• Start standing with your feet hip width apart.
• Drive your right knee up to hip height.
• Return your right foot to the ground.
• Repeat with your right leg.
• Continue to run your knees up, pumping your arms, and alternating your legs.
• Repeat for 30 seconds.