Garmin Forerunner 735XT review

When it comes to Garmin watches, if you see an XT you know this device is built for serious training – these are the multi-sport specific devices. Since the release of the bulky Garmin Forerunner 920XT, the company has had its engineering wizards working on overtime to shrink the wrist-dweller to what's here in the Forerunner 735XT.

Despite being small enough to wear day-to-day, the 735XT crams in a powerful battery, optical heart-rate monitoring, all-day activity tracking, smartphone notifications and plenty of training metrics. But does it stand up to the competition from Polar, Suunto and TomTom?

The $449.99 price tag places this above some high-end running watches but below more comprehensive multi-sport wearables. Has Garmin found the sweet spot that makes this ideal for everyone? We got sweaty to find out.

When you consider how much this watch offers, the GARMIN FORERUNNER packs everything into a relatively small body. It's light and thin enough to complete a full triathlon without worrying about noticing it – even when slipping off your wetsuit. But it also looks a bit basic.

We're all for minimalist designs and have to admit this does do everything you could need. There's a good enough sized colour screen and functional, easily controlled buttons that make for ideal access while bouncing about on a run.

The gripe? It could be better looking: less bezel, more metal and a punchier screen. The Polar V800, for example, has a great mix of metal and coloured buttons to add a bit more of a stylish feel. But if it's a toss-up between looks and functionality most sports watch makers, including Garmin, seem to go for the latter.

The strap on the Forerunner 735XT is excellent, with a slight stretch to the rubberised material. This makes for a snug yet comfy fit, which is ideal for holding the watch in place to get the most accurate wrist measured heart rate.

The optical heart-rate monitor is automatic when left on, allowing the device to save battery when not in use. The problem is this isn't so smart. We found that even with the watch off, on a table, the heart rate light remained on for a little while before cutting out. That said, battery life wasn't massively affected so it's not a big deal.

The watch can also be bought with an optional heart-rate strap which delivers greater data metrics thanks to that more accurate measurement.

When it comes to the core events of running, cycling and swimming the 735XT has everything covered. Track indoor training using the motion sensors or head outside using the GPS – an ideal option when it comes to pool and open water swimming. But it's the deep data metrics that make this special.

The built-in heart rate monitor can be used for training in zones, or for at-a-glance feedback, but a chest strap still offers more accuracy and even more metrics. When activity trackers started using optical heart rate the serious GPS companies like Garmin and Polar held off, saying chest straps were superior. Then a certain fruit named gadget manufacturer plonked optical heart rate on its first wearable and Garmin folded to the will of the people.

So while the optical heart-rate monitor is there to please everyone, Garmin still offers chest straps for the more serious athlete that wants supreme accuracy and the resultant data.

With the chest strap in place you can benefit from running dynamics that measure – deep breath – vertical oscillation, ground contact time, cadence, stride length, vertical ratio, ground contact time balance and even an estimated lactate threshold figure, recovery time and VO2 max. If all that lot isn't clear enough, for the less hardcore you can turn on virtual partner and set that to a pace you need to follow – ideal for specific race finish goals.

Swim tracking is pretty much spot on for length count thanks to the auto stroke detection system. On a 1,000m swim we found it to be one length out in a 50m pool – although that might have just been our pesky fleshy brains miscounting when tired. However if you're planning on stopping and starting you will need to press pause, as this doesn't do it automatically like the Suunto Ambit3 Vertical, for example. Despite the built-in heart rate monitor, you'll need the tri-chest strap to track heart rate as all that water sloshing disables the wrist HR tracking.

When cycling the data is accurate thanks to Garmin GPS smarts, but we'd say that the optical heart-rate monitor can get glitchy here. If you're riding a racer the drop-handlebars can flex your wrist muscles in a way that works the watch off your wrist and down to your hand, we found. Tightening the strap helps sort this but it's verging on uncomfortable, so we opted for the chest strap when out on the bike.