Is Your Fitness Tracker the Most Accurate on the Market?

Fitness trackers are becoming increasingly popular as more Americans are turning to technology to help motivate, evaluate, and improve their workout sessions. 1 out of every 6 consumers in the U.S uses some type of wearable technology such as a fitness band or smartwatch. Historically, the most precise heart rate monitors have used chest straps and electrode attachments such as the Polar heart rate monitors. However, more recently today’s fitness trackers use optical sensing technology that goes further than just monitoring heart rate it also analyzes body temperature, perspiration, oxygen saturation, and physical and electrical activity of the skin.

A study last year compared the accuracy of five wearable heart rate trackers that use optical sensors to gain an understanding of just how accurate they can be. The study had 50 aerobically active men and women complete a 4.5 minute light, moderate, and vigorous exercise sequence (1.5 minutes each) on the following four pieces of equipment: treadmill, stationary bike, elliptical trainer with arm levers and without. Subjects rested 2 minutes after completing each modality. Each participant wore standard electrocardiograph (ECG) leads, a Polar H7 chest strap, a Scosche Rhythm+ on the forearm, and 2 of the following: Apple Watch, Fitbit Blaze, Garmin Forerunner 235, TomTom Spark Cardio on each wrist. The scientists compared the accuracy of the devices to that of the ECG. An ECG correlation above .80 was considered acceptably accurate. The table below shows results for each device on each modality.

Heart Rate Device	Treadmill	Bike	Elliptical with Levers	Elliptical without Levers	Average
Polar Chest Strap	.99	.99	.99	.99	.99
Apple Watch	.93	.88	.94	.75	.88
TomTom	.88	.77	.55	.76	.74
Garmin	.92	.91	.54	.31	.67
Scosche Rhythm+	.92	.84	.27	.41	.61
Fitbit	.76	.41	.58	.48	.56

As you can see from the chart above, Polar Heart rate monitors are still the most accurate tool for measuring heart rate across different modalities and intensities. Most consumers prefer the convenience of many optical sensing monitors also evaluated. As proven from the table above Apple Watch comes in second as the most accurate tracker and the most popular amongst consumers the Fitbit came in last.

When designing your workouts and trying to get the most of your sweat sessions, and especially when trying to improve performance, chest strap heart rate monitors still prove to be the gold standard and most accurate piece of technology on the market. The Apple Watch is a close second.