Limited Validity of the Low-Cost Coospo H808S Heart-Rate Monitor Compared to the Polar H10

This study assessed the validity and agreement of the low-cost Coospo H808S chest-strap heart-rate (HR) monitor compared with the Polar H10 during varied conditions.

Fifteen recreational runners (25 [5] y) participated in the study. Each participant wore both the Polar H10 and Coospo H808S simultaneously, with strap placement randomized. HR and HR variability (HRV) were recorded for 5 minutes in 3 conditions: supine, seated, and low-intensity running (rating of perceived exertion 2-3/10). The last 4 minutes of each recording were analyzed using Kubios HRV software, with both raw and medium-filtered data. Agreement between devices was evaluated using intraclass correlation coefficients (ICCs) and Bland-Altman plots.

The raw data of the Coospo H808S demonstrated excellent agreement with the Polar H10 for HR and HRV in the supine condition (ICC > .96, P < .001). In the seated position, agreement remained excellent (ICC > .99, P < .001). During running, the HR agreement slightly decreased (ICC = .94, mean bias = -2.35), and root mean square of successive difference showed a marked reduction to poor agreement (ICC = -.24, mean bias = +17.6 milliseconds). After applying the filtering to the running HRV data, the agreement remained poor (ICC = .13, mean bias = -5.1 milliseconds).

The Coospo H808S is a low-cost valid alternative to the Polar H10 for HR and HRV assessments in resting conditions and HR during running, but it presents divergences during low-intensity running for time-domain vagally related HRV indices. Researchers and practitioners should be cautious when using HRV data from low-cost monitors in dynamic conditions.