Whether you’re looking to improve your cardiovascular health for sport or general wellness, there are a few key things you’ll want to learn to make this process as efficient and effective as possible. This guide is all about teaching you heart rate zones and how you can use these metrics to fast-track improving your cardio.

The American Heart Association (AHA) recommends that individuals aim for at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity cardio each week. Activities like running, cycling, swimming, or HIIT (High-Intensity Interval Training) are great options. But what the heck does that actually mean?!

Measuring Your Heart Rate During Activity

You’re going to need a heart rate monitor of some kind to see exactly what your heart rate is while you’re exercising. One of the most common ways to do this today is by using a smartwatch like a Garmin or an Apple Watch. Personally I use the Garmin fēnix^® 6S – Pro Solar Edition. 

It’s All About Cardio Zones

Cardio zones are different heart rate ranges that correspond to varying levels of exercise intensity. These zones are typically calculated as a percentage of your maximum heart rate (MHR), which is roughly estimated by subtracting your age from 220. This is a quick-and-dirty way of calculating it, but you can also get this professionally tested to know exactly what your MHR is.

1. Warm-Up Zone (50-60% MHR):

   • This zone is ideal for warming up and cooling down. Your heart rate is elevated, but not working hard enough to count as moderate-intensity exercise.

2. Fat-Burning Zone (60-70% MHR):

   • Moderate-intensity activity falls within this range. You’re burning fat as fuel, and this is the minimum intensity needed to count towards the AHA’s recommendation of 150 minutes per week.

3. Cardio Zone (70-80% MHR):

   • This is a higher intensity where you’re improving cardiovascular fitness and endurance. Exercise in this zone counts as moderate to vigorous intensity, contributing to both the 150 minutes of moderate or 75 minutes of vigorous activity per week.

4. Anaerobic Zone (80-90% MHR):

   • This vigorous intensity zone is where you’re pushing your limits, improving your anaerobic capacity, and increasing strength. Spending time in this zone contributes to the 75 minutes of vigorous activity per week.

5. Maximal Effort Zone (90-100% MHR):

   • This zone is reserved for short bursts of very intense exercise. It’s not sustainable for long periods but can significantly boost fitness levels.

Calculating Your Moderate Intensity Requirements

To meet the AHA’s guidelines, aim for 150 minutes per week in the heart rate zone that’s 60-70% of your maximum heart rate. Your maximum heart rate is generally calculated as 220 minus your age. Once you have your max heart rate, multiply it by 0.6 and 0.7 to find your target heart rate range for moderate-intensity workouts.

Example: If you’re 40 years old:

• Maximum heart rate: 220 – 40 = 180 beats per minute (bpm)
• 60% of max HR: 180 x 0.6 = 108 bpm
• 70% of max HR: 180 x 0.7 = 126 bpm

So, for moderate intensity, your heart rate should be between 108 and 126 bpm for a total of 150 minutes per week.

Calculating Your Vigorous Intensity Requirements

For vigorous activity, the AHA recommends 75 minutes per week in a heart rate zone that’s 70-90% of your maximum heart rate.

Example: Using the same 40-year-old person:

• 70% of max HR: 180 x 0.7 = 126 bpm
• 90% of max HR: 180 x 0.9 = 162 bpm

For vigorous intensity, your heart rate should be between 126 and 162 bpm for a total of 75 minutes per week.

By understanding and utilizing cardio zones, you can effectively use your fitness watch to ensure you’re meeting the AHA’s recommendations for exercise. Whether you’re focusing on moderate or vigorous activity, staying within the correct heart rate zones will help you achieve optimal fitness and health benefits.

Always consult your doctor before starting a fitness program.