How accurate is Garmin heart rate?

By Coach Hunter Bennett

Garmin watches have become increasingly popular over the last few years, regularly used by athletes and recreational runners across the globe to track heart rate.

But how accurate are Garmin watches for heart rate?

How Do Garmin Watches Measure Heart Rate?

Garmin watches use optical heart rate technology, commonly referred to as photoplethysmography (PPG), to measure heart rate.

This technology shines green LED lights into your skin to detect changes in blood flow through the blood vessels in your arm. Using this data, they can estimate your heart rate.

However, this does have some limitations.

How Accurate is Garmin Heart Rate?

Garmin watches (and other wrist-based heart rate monitors) have decent accuracy during lower exercise intensity exercise. However, research has shown that as exercise intensity increases, their accuracy decreases.

In fact, it is not uncommon to see individual measurement variation of up to ~30 beats per minute when compared to laboratory heart rate measures, which is pretty large.

Why is this the case?

• Blood Flow Variability: At higher intensities, blood flow moves rapidly to the working muscles. This can create issues for wrist-based sensors, which need steady blood flow close to the skin to accurately estimate heart rate.
• Increased Movement: When you’re running fast, arm motion can interfere with the sensor’s ability to track heart rate correctly. This is less of an issue when you’re walking or jogging slowly, and arm movement is more stable.
• Sweat and Skin Tightness: High-intensity workouts often mean sweat, which can affect the device’s ability to maintain close skin contact. Also, if the strap is too loose or too tight, readings can fluctuate.

Individual Factors That Affect Garmin Heart Rate Accuracy

It is also important to note that other individual factors can impact the accuracy of your Garmin watch.

The accuracy of Garmin heart rate is impaired by things that impede light transmission through the skin. This includes having a higher body mass index, having tattoos, and having a denser arm hair.

There is also evidence suggesting that these devices are less accurate for those with darker skin tones.

How to Improve Garmin Heart Rate Data

The good news is there is an easy way to improve the accuracy of your Garmin – get a chest strap.

Chest straps use electrocardiography (ECG) to directly measure your heart’s electrical activity, avoiding the limitations that come with wrist-based measured. This means they provide a much more accurate measurement.

In fact, research has shown that commercial chest straps have a near perfect association with laboratory based heart rate monitors, making them a great option.

How Accurate is Garmin Heart Rate: Final Takeaway

While your Garmin watch can be fairly accurate when walking and jogging slowly, this accuracy can decrease rapidly at higher intensities.

If you are someone who cares about the accuracy of your heart rate data or enjoy performing a lot of high intensity exercise, then getting a chest strap that syncs to your Garmin watch might be the best option.

If you are looking for a gym program but are not sure where to start, check out some of our programs or feel free to contact us for more information.