To reap the benefits of low-intensity cardio, make sure what you're doing actually is low intensity. If you're used to performing sprint workouts or high-intensity cardio, you may slip into your old habits and hinder progress toward your current goals. Low-intensity cardio is performed at between 40 and 60 percent of your maximum heart rate. Calculate your maximum heart rate by subtracting your age from 220. Multiplying that number by 0.4 and 0.6 will give you the end points for your low-intensity cardio range.