This 30-Minute HIIT Cardio Workout Can Be Done Anywhere and Requires Zero Equipment

• Start standing with your feet hip-distance apart.
• Walk in place, driving your knees about half way up to your hips and pumping your arms. Make sure you're standing tall and pull your abs toward your spine to keep your core engaged.
• Continue for 30 seconds.

You can also use this as your active recovery exercise during the circuit.