About six months after I began using my Suunto Ambit GPS watch, I bought the paired Dual Comfort Belt so that I could train based on effort, as measured by heart rate. After 18 months of nearly daily use, and now on my second strap and third battery, I feel confident in offering a long-term review.
The value of heart rate
Before addressing the Dual Comfort Belt specifically, I want to briefly discuss the value of heart rate data. As an ultra runner who trains at altitude primarily on mountainous trails, I personally find heart rate to be a more valuable data point than my pace, which fluctuates wildly based on the trail’s slope angle. I use heart rate mostly to exert discipline:
- By capping my heart rate on a run, an easy day remains easy; and,
- By capping my heart rate early in a race or long run, I avoid depleting myself prematurely and slowing down dramatically later.
I seldom do tempo runs, but on those occasions I have used heart rate to ensure that my effort was hard enough. For example, I’ll let my HR climb into the low-160’s and then keep it there for an hour.
Suunto offers three heart rate belts, each with different compatibility:
- Smart Belt, for Suunto Ambit3 watches and bluetooth-enabled devices like your smartphone;
- Dual Comfort Belt, for pre-Ambit3 watches and non-GPS Suunto HR watches, plus compatible gym equipment like treadmills and stationary bikes; and,
- ANT, also for pre-Ambit3 watches and non-GPS Suunto HR watches, but not gym equipment.
On a man especially, the Dual Comfort Belt looks odd and dorky. You might hesitate before running shirtless; since I wear a shirt anyway to protect my skin from the sun and my running vest, it’s less of a concern for me.
The Dual Comfort is low profile and I barely notice that it’s there. It’s never caused any chafing. And so long as I wet it beforehand, it stays put — I rarely must fiddle with its position.
If not washed regularly, the Dual Comfort Belt will begin to smell like unwashed running apparel — because, essentially, it is. I wash mine daily, during my post-run shower.
Before you can use the Dual Comfort Belt, it must be paired with your Suunto watch. If you own a Ambit or Ambit2, watch this video. The process is uncomplicated and worked as designed for me.
There are similar videos for the Smart Sensor and ANT belts, and other Suunto watches.
I’m optimistic that wrist-based heart rate monitors will replace chest straps within a few years. But for now their accuracy sounds too questionable for my tastes. Plus, no high-end GPS sport watch like the Ambit family or the Garmin Fenix 3 has this feature yet.
The Dual Comfort is unreliable only in a few instances. If the belt sensors are not at least damp when I begin my run, HR readings will be way off until I begin to perspire. I solve this problem by soaking the belt and sensors before I walk out the door. This also helps the belt to stay in place.
The accuracy of the Dual Comfort also declines when the belt or battery needs replacement. A few weeks ago, for example, towards the end of my run I noticed that my HR dropped into the double-digits even though it was probably in the 130’s or 140’s. It happened again the following day, but even worse. I solved the issue by replacing the battery.
In November I was having a similar issue, but I traced it to the belt, not the battery. After 300+ hours of use, the sensor was not as reliable as it should be been, due to degradation of the sensors or lost elasticity in the belt.
According to my Strava profile I ran nearly 2,500 miles last year in about 350 hours. On most of my runs, I wore my Dual Comfort Belt.
A few weeks ago I replaced the battery for the second time, which to me indicates very long battery life. And in late-November I replaced the belt (but not the sensor). While that sounds admirable, frankly its craftsmanship is poor and the durability could be much better. This is the only complaint I have about the Dual Comfort Belt.
On both of my belts, within a few weeks of use the welded seams between the sensor straps and the elastic began to fail. Spandex fibers are visibly pulling out of the seam, which compromises the elasticity of the belt, increasingly over time. This flaw is very annoying: it is mentioned by countless reviewers, and the design fix is easy and inexpensive — the welded seam must be wider and/or reinforced with some stitching. Come on, Suunto.
Disclosure: I spent personal funds on the Dual Comfort Belt. This post contains affiliate links.