Wearable technology has become not only a way to track steps, caloric expenditure throughout the day, but now a fashion statement as well. Apple watches, Fitbits, Polar and Garmin watches all offer heart rate monitoring that have become a viable tool for not only the fitness oriented person, but also for the average individuals looking to gauge their daily activity levels. However, as opposed to the traditional chest strap transmitter with wrist watch display, recent technology has started to utilized wrist based light therapy to monitor blood flow and in turn display resting and active heart rates (Stal, An, Dinkle, Noble, & Lee, 2016). Yet, these fashion based fitness trackers do not have the backing of scientific literature despite the appeasing display and usability. By 2012, consumers spent over $800 million on watches, bands, and bracelets to monitor heart rate using a method that has not widely been validated or even studied (Stal et al., 2016).
At Revolution Physical Therapy and Weight Loss, we utilize heart rate monitors to ensure our patients are working within the correct heart rate zones to optimize weight loss. Our Polar monitors utilize the chest strap transmitters that might seem far past their prime in regards to their technology, but they have been scientifically researched. Since the introduction and influx of these new wrist based light therapy devices in the current fitness market, only a few studies have examined their validity. As the new wrist based heart rate monitoring is on the rise, the traditional chest strap still continues to be a step above and the most reliable in comparison with an EKG. When compared to the EKG, the HR monitors had variable accuracy as assessed by the concordance correlation coefficient. The monitors tested were Polar H7, Apple watch, Fitbit, Mio Fuse and the Polar H7 had the highest correlation coefficient (.95 with a 95% CI) (Apple watch .91 with a 95% CI; Mio Fuse .91 with a 95% CI; Fitbit .84 with a 95% CI) ( Wang, Blackburn,Desai, Gillinov, Houghtaling, Gillinov, 2017).
Ensuring that our patients are working within their prescribed zones is essential for their success. Reliable and accurate real time heart rate monitoring is a key factor in this process. While the wrist based heart rate monitors do provide the advantage of blood flow monitors, their accuracy and validity are not fully established. When heart rate measurement is imperative as it is at Revolution, chest strap monitors should be utilized when available (Gillinov et al, 2017).
Engström, E., Ottosson E., Wohlfart, B., (2012). Comparison of heart rate measured by Polar RS400 and ECG, validity and repeatability. Advance Physiotherapy ;14:115–22.
De Rezende Barbosa M.P.,Silva N.T.,De Azevedo .FM., (2016). Comparison of Polar RS800G3™ heart rate monitor with Polar S810i and electrocardiogram to obtain the series of RR intervals and analysis of heart rate variability at rest. Clinical Physiological Function Imaging;36:112–17.
Stahl, S.E., An, H., Dinkel, D.M., (2016). How accurate are the wrist-based heart rate monitors during walking and running activities? Are they accurate enough? BMJ Open Sport and Exercise Medicine 2016; 2.
Gillinov.S., Etiwy, M., Wang, R., Blackburn, G., Phelan, D., Gillinov, A.M., Houghtaling, P., Javadikasgari, H., Desai, M. Y., (2017).Variable Accuracy of Wearable Heart Rate Monitors during Aerobic Exercise. Medicine and Science in Sport and Exercise. 49(8), 1697-1703