Heart rate variability (HRV) is a versatile and powerful biometric. Wearable health tech companies rushed to create HRV monitors in many form factors. We wrote about Emfit Limited’s Emfit QS that unrolls and claims to measure HRV accurately through your mattress while you sleep at night. toSense’s necklace-like CoVa Monitoring device may be the most attractive wearable HRV tracker available today. Even fitness tracker companies have entered this game, as evidenced by the Fitbit Alta HR.

According to Elite HRV, whose own CorSense HRV tracker is currently in a Kickstarter crowdfunding campaign, there are several important reasons why a handheld sensor is better than a wearable. Elite HRV claims many wearable users get tired of the 24/7 aspect of continuous monitoring and stop wearing tracking devices by the end of the first six months. The company also claims that not only is 24/7 monitoring unnecessary, but many wearable HRV monitors are not very accurate. We’ll leave accuracy comparisons to independent testing agencies, but let’s focus on why CorSense says its device has a high degree of accuracy. Customers use the handheld CorSense for just two minutes a day. According to Elite HRV, the CorSense wearable is comparable in accuracy to a 5-lead  electrocardiogram (ECG) for both HRV and pulse waveform. CorSense processes data from multiple LEDs using onboard algorithms and filters. The device also has physiologically optimized sensors and fast sampling rates. CorSense captures a full cardiac pulse waveform for accurate measurements of HRV and the heart at rest. CorSense raw data feeds to the Elite HRV app, but the platform is completely open source so you can transmit the data to any open HRV app with Bluetooth connectivity.

If Elite HRV’s claims about wearable HRV trackers are correct that wearables cannot measure heart rate variability as accurately as the CorSense model, the allure of wearing a watch or a necklace or a brooch that works all the time to monitor significant biometrics could fade quickly. The next step would be to question if other popular function wearables should be put aside in favor of more accurate handheld devices.