Think about how you feel on the treadmill versus during a high-intensity interval workout: You probably feel like you could maintain that steady-state for a pretty solid amount of time without wheezing, while just one round of HIIT leaves you gasping for breath.

That difference is important to understand because it’s how you can tell aerobic vs. anaerobic workouts apart. Your body creates energy in two basic ways: anaerobically (without oxygen) and aerobically (with oxygen), and each of those methods will affect your body differently. Understanding that process can help you burn calories and fat—plus increase your overall strength, power, and endurance.

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