For those of us who are aging-athletes with many decades of ultra-endurance training and competition and consequent cardiovascular issues, the metrics FF X2 provides are indispensable to be able to see in real-time. For me, those data, when combined with real-time measurement of muscle oxygen and watt output allow me to calibrate my work to enhance safety and fitness. To my knowledge, there are no other wearable monitors at the price point of the X2 and Premium subscription that can provide such data.

Quick background--I had been having some irregular heart beats during exercise and was looking for a way to investigate what was going on. Found the Fourth Frontier X2 online. I use it every time I workout now and also when I sleep. I have gotten a lot of great insight into my heart health and am quite happy with the product. The X2 is helping me and my doctor manage my newly diagnosed Atrial Fibrillation. --The Heart Strain indicator is quite helpful. I have had the "buzz" on the device go off a couple of times. It tells me to lower my workout intensity. --The heart rate is accurate--as compared with my Polar H10 strap and several manual counts. --Breath rate is helpful information not supplied by other heart rate devices --The HRV reading is helpful and compares very close to my Oura ring. --Sleep data is impressive and compares very close to the Oura ring. --The X2 could easily take the place of the Polar H10 strap and Oura ring. --The App is intuitive and provides a lot of useful information. --I love that the app will generate a PDF of the ECG that can be emailed to your cardiologist/doctor. --I love that the X2 is charged via USB instead of a battery like the H10. --Battery life is impressive--I have worn it all night while sleeping followed by 3 hours of use during exercise and have not gone below 70% charge. I once wore it for 18 hours and only got to 60% charge. The X2 charges in just a few minutes-much faster than my Apple watch. --My cardiologist was enthusiastic about my use of the X2. He found the ECG data useful--especially because he could see what was happening during a specific activity. I had worn a 2 week monitor through him--but of course I didn't have any weird beats until after I turned in his device. The X2 ECG is helping to guide my treatment.

If you want to really learn about your heart health and what impact it, this is the device. I’ve used many health devices, and they all more or less give you the same data. While that data is informative, I wanted deeper insights into my heart health and Fourth Frontier does this better than any device I know. Yes, it’s on the pricier side and I was reluctant about that, but the great thing is that you can get a full, one-on-one demo. I talked with Vijay Kumar who took the time to walk me through what it does, answered all my questions, and made sure the device is a fit for my needs. I was looking for a device that would give me all-day readings, and he showed me exactly how it could do just that. So, the purchase was seamless. I never felt rushed or pressured. The device itself far outdid my expectations. I was nervous about whether the battery would give all-day readings, and it does. The readings give me much better insights into my heart function than any device I’ve tried. What’s even better is that you get a consultation with a real healthcare professional who helps you understand your readings. I learned more in that session than months and years of data from other sources and/or doctor visits. Both the mobile device and the desktop dashboard give you a lot of insights. Finally, in just the few months I’ve owned this device, they have updated and added features and services so that the device and the information continue to improve. As someone who loves to try out new tech and learn about my health through insights, I’m super impressed!

I've had lots of exercise monitors over the years but was looking for one with multiple and extensive features. The Fourth Frontier X2 is an excellent monitor providing me with all the stats I'm interested in for a heart monitor...as well as special features such as an indication of VO2 Max (with the premium membership). Also, customer service has been excellent vie email whenever I've had a question.

I can't find information on, what you call, 'Noisy signal/Not interprable 'Grey background'. The instrucion-picture does not show the 'Grey background' I find in my grafics? Noisy signal can be an Technical matter or an Hartmatter or both!? I see this grey background on a regular base. I know the meaning of flags in the grafics. I have them alwais! That's wy I bought this device.

Placed order more the 2 weeks (delivery 3-5 days). Contacted via Live Chat. They would investigate and contact me back (no response for almost a week now) Filled in contact form... nor response. Not even that they received the form or that they would investigate. Very poor customer support. On the product(s) itself I cannot comment, because I have not received them. But hey... they got the money. So why would they care...

The Frontier X is an excellent product, backed by a team that listens to its customers and responds promptly—a refreshing approach in today’s market. It may be the best heart rate monitor for fitness enthusiasts.

Not sure where all these other reviews have come from but in general, for a device that costs in excess of £350 - it's very poor. I use the HRM for variety of exercises - mainly treadmill running, HIT and kickboxing. My main concern and issue is the amount of 'noisy rhythm' that gets reported, generally resulting in a useless and overpriced HRM unfortunately. My past 4 activities have resulted in 27%, 40%, 30%, and even one activity had 80% noisy rhythm. Customer service informs me of the usual tactics to ensure contact, proper position etc. But the amount of items that can seem to interfere with this device is crazy. Zips or metal on your workout gear, even static generated by your clothing can cause interference. For a device that costs this much, that is just plain ridiculous. Back to Garmin and Polar it is.

The sales pith was good. But after the sale was supposed to get done furyher assistance re set up and setting parameters. Also called technical support. This was call centre in India, said they would email me the answer. No response for weeks. Device also gives spurious readings. Would not recommend

Avoid this company. They potentially have a great product if they could sort out these issues, poor quality materials, bugs in the software and poor customer service. I bought my unit in August 2023 and generally it was ok, it started to go wrong in January 2024. The customer service team refused to acknowledge that there was an issue and kept sending me the same instructions to reboot the unit, which worked for a day or two, but this became tedious. Finally after 5 months of no action from them I managed to get them to agree it was a faulty unit and to replace it. The replacement unit worked fine for 3 months and now it wont charge using their bespoke charging cable. As I am over 12 months from original purchase, even though the replacement is 3 months old they wont replace the cable. They are a very difficult company to deal with if you have an issue, they won’t accept the problem is with their equipment. Update, since this review they have resolved the issue by sending out the replacement cable.