Optical Heartrate

The Suunto 9 Baro comes equipped with the latest generation PerformTek 1.2 sensor from Valencell, which is one of the best optical heart rate sensors out there. No matter how good it is though, no optical heart rate sensor can match the accuracy and precision that heart rate belts like the Suunto Smart Sensor give.

Despite this, the optical sensor does seem to do quite well, at least once you manage to find your own sweet spot. You see, the accuracy of optical heart rate sensors depend on a huge range of factors: how much you are sweating, the position of the watch on your wrist, how tight the watch straps are, the ambient temperature which affects your blood flow, and factors like how much your arms move and whether you tend to clench your fists or not. Once you do find the right position however, the results will fairly accurately follow the 'trend' of your heart rate. The graph does spike and drop on occasion but the trend is indeed there:

If it were up to me however, I would have left it out to save weight and reduce the cost, and for the time being at least, will still continue to use the Suunto Smart Sensor for my runs. I also do realise that optical heart rate sensors have been added to Suunto watches before, but this write-up is a comparison between the flagship models, and this is the first time an optical sensor has been added to Suunto's highest end device.

Baroless Option

The baroless option--referred to as (just) the Suunto 9, as opposed to the Suunto 9 Baro--was announced just a month ago. The biggest physical changes on the Suunto 9 are the different chevrons on the cardinal points of the bezel, the straps now lie flat, and of course the lack a barometer port on the underside of the case.

The lack of a barometer also slims the Suunto 9 down slightly, and reduces its width by 0.3mm. This, and the change from a sapphire crystal to mineral glass display, make the weight difference quite considerable--a reduction of 9g, more than 10% the total weight of the watch. This weight reduction should, at least theoretically, increase the accuracy of the optical heart rate readings since the watch will be less likely to flop around on your wrist. The lack of a barometer does not mean that altitude readings have been completely omitted however, as the watch still takes GPS altitude readings which, although not completely precise, still manages to capture the ascents and descents. The Suunto 9 may have been announced but it is still in its pre-production phase, and as such, my field tester NDA prevents me from releasing any test results. At least, not at this time.

So, to wrap-up.. here are the pros and cons:

• Amazing battery life of up to 120 hours with GPS tracking.

• Intelligent battery modes and warnings.

• Swappable straps without additional tools.

• Rugged and can withstand the demands of the outdoors.

• Has a very sleek modern appearance.

• The Suunto 9 requires a figure-of-eight arm movement to re-calibrate the compass each time FusedTrack is enabled. Whilst this may indeed be necessary for improved FusedTrack accuracy, the wild flailing does attract a lot of unwanted attention.

The Take-away

The results that the FusedTrack algorithm produces are nothing short of extraordinary. The Suunto 9 Baro (and Suunto 9) can effectively track routes relatively well without the presence of a GPS signal. This in turn allows the amount of time that goes by between each GPS sampling point to be extended without adversely affecting the accuracy of the GPS tracking, which subsequently results in a battery life that is vastly extended.

The device also comes with an array of intelligent and customisable battery modes and settings that boost the battery life even further, which is ideal for ultra runners or for those who are out in the wilderness for multiple days at a time. The accuracy of the GPS and the barometric altimeter readings, and the navigation capabilities of the watch are perfect for those who call the mountain wilderness their home. The sleek yet robust form factor will also be able to withstand almost anything that demanding weather and terrain can throw at it.

This is a watch that has indeed been 'built to last'.