Fourth Frontier Continuous ECG to measure heart strain

Hi all, I’m wondering if anyone has tried the Fourth Frontier X2 continuous ECG monitor? It is supposed to measure heart strain so you don’t over-tax your heart. Which is important because I’m in my fifties and because it relates to my other question on doing Sprint Interval Training to increase FTP here: Sprint Intensity Intervals to increase FTP.

Has anyone tried this device? Is it just a gimmick, or does it really work to help you understand the strain level on your heart for example during hard intervals?

FWIW, I have had the Frontier X2 for the past 3-4 months. I intend no disrespect to Frontier. I also want to be candid: their customer service leaves a whole lot to be desired. E.g., putting up a post as to a topic, and, it was in moderation limbo. It never did get “moderated.” And it had to be with a serious issue of assessing the significance of PSVT events. The Heart Program subscription for $150 a month left me in limbo awaiting the link that would have allowed me actually to get a Cardiologist to provide commentary on that issue. So, I quit that program.

The HR monitor itself is a heart rate monitor. Cardiac Strain is a proprietary metric based upon data they own, if I understand their site correctly. The device itself appears far more susceptible to artifact than either my Polar H10, but especially compared with the rock solid Movesense Medical device. FWIW, each of those devices can provide realtime ECG while doing a workout.

The recommendations for upcoming workouts are insipid, so I won’t take up bandwidth, and that’s especially true if you’ve been working out on programs like or you have your own coach or you are familiar with PerfPro.

End of story: I’ve quit using it, relying instead on the data from VO2 Master to provide connections to all my sensors, to include my Smart bike from Wahoo, two Moxy monitors, my Movesense MD HR monitor and I get power, cadence, speed from either the Kick or my Assioma pedals.

I wasted $500 on Frontier. You can also do a YouTube video search to find out what other folks have had to say about their use of the program.

Hope this helps, Anthony

1 Like

@Anthony_S thanks a lot for your reply and review. Based on that it looks like the Frontier X2 is not ready for prime time yet. The Movesense sounds pretty good but it doesn’t look like a consumer-ready product I could purchase. I already have a Polar H10 but I don’t know how I would get it to show continuous ECG during a workout on a head unit like Wahoo or Karoo 2.


You’re welcome and IMHO exactly correct with regard to “prime time.” Movesense can be reviewed at Muscle Oxygen Training: Muscle Oxygen Training blog index. Dr. Rogers is brilliant AFAIC. Further, Movesense has it’s own dedicated application that allows me to see my ECG in real-time when installed on my iPhone. Moreover while using, e.g. can swipe between the Movesense app and the Xert app to see the metrics important to me. I’m doing that, however, on my indoor Kickr Smart Bike. So, if you’re riding out doors that may prove to be a clunky operation. The other thing to keep in mind is that Kubios Premium is expensive and only the expensive version allows ECG data to serve as the basis for its calculations of the multiple parameters of cardiac function that it records. While also not primetime, in fact it’s only in alpha version now, is on the horizon. I hope this helps. Anthony