Garmin HRM 600 vs Fourth Frontier X2: Which Chest Strap Wins

The Garmin HRM 600 and Fourth Frontier X2 sit at the top of the chest strap market, but they are built for very different athletes. The HRM 600 is a pure performance tool, feeding accurate HR, HRV, running dynamics, and lactate threshold data straight into your Garmin ecosystem. The X2 plays a bigger game, adding ECG, VO2 max estimation, atrial fibrillation detection, and continuous cardiac monitoring you would normally need a medical device to get.

For data accuracy, the HRM 600 is hard to beat during high-intensity work. It pairs seamlessly with any Garmin watch (Forerunner 965, Fenix 7, Epix) and adds running dynamics like ground contact time and vertical oscillation that the X2 simply does not offer. If you are chasing race-day performance data or dialing in lactate threshold zones, the HRM 600 is the sharper tool for the job.

The X2 costs significantly more, around $399 vs roughly $130 for the HRM 600, and that premium buys you clinical-grade heart health features. The built-in ECG and AFib screening put it in a different category than anything Polar, Coros, or Whoop currently offer in a chest strap form factor. For masters athletes or anyone managing cardiac risk, that is a meaningful difference.

Battery life separates them too. The HRM 600 runs for around 500 hours in standard mode. The X2 delivers closer to 24 hours of continuous monitoring, which limits how you can deploy it across a full training week. You would not wear the X2 as a daily driver the way you might the HRM 600 during every session.

Buy the HRM 600 if you train with Garmin and want the most accurate performance metrics for the money. Buy the X2 if heart health monitoring is your priority and the price does not sting. Two good straps. Two completely different jobs.