Garmin Forerunner 945 review

The Garmin Forerunner 945 is a GPS sports watch for those who don't mess around, offering in-depth training analysis and tracking to triathletes and runners aiming to excel at their next events.

Its predecessor, the Forerunner 935, took the features of the Fenix 5 watch and popped them into a lighter, plastic frame. Garmin has more or less repeated that approach here, but this time it's taken the features of the Marq Athlete luxury sports watch and put them into the slimmer, lighter Forerunner 945. That means the 945 actually has one or two tricks up its sleeve that the pricier Fenix 5 Plus range doesn’t.=

The 935 came out in 2017 and Garmin has come a long way since then, especially in terms of the smart features if offers on its watches, all of which are on the 945. You get music storage and the ability to sync with streaming services like Spotify, NFC payments through Garmin Pay, and navigation features with colour maps and on-the-go routing.

Those smart features are all very well, but it’s probably the updated training analysis offered by the 945 that will most excite its core audience. The new training load analysis displays how much time you’ve spent working in different aerobic and anaerobic zones over the past four weeks, and suggests how you might tinker with your training balance to be more productive. The 945 also has a pulse oximeter sensor to track how well you’re adapting at altitude, and will monitor your acclimation to hot conditions.

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The Forerunner 945 costs , or for the Tri Bundle, which includes two heart rate chest strap monitors. It’s expensive, then, more so than Polar and Suunto’s flagship watches – the Polar Vantage V and Suunto 9 Baro. However, the 945 is cheaper than Garmin’s Fenix 5 Plus range, and it has a feature set that’s as good as anything on the market.

We've been spending serious hours getting to know the 945 to see what it's made of. Here's our full verdict.

Garmin Forerunner 945: Design and comfort

If you’re familiar with the Forerunner 935, there are no surprises here – the 945 is almost exactly the same with dark grey buttons instead of silver. The 945 has a plastic body, which makes it smaller than the more expensive Fenix 5 Plus and Marq Athlete watches. It's lot lighter in fact; the 945 is 50g compared to 86g for the Fenix 5 Plus and 94g for the Marq Athlete.

That lack of weight plus its slim build – the 945 is 13.7mm thick, which is slightly more slender than the 935’s 13.9mm – make it an incredibly comfortable watch to wear at all times.

Spot the difference: Forerunner 945 (left) and Forerunner 935 (right)

The 945 has the same 1.2-inch, 240x240 screen as the 935, Fenix 5 Plus and Marq Athlete watches – Garmin doesn’t vary a lot when it comes to screens on its watches. It’s not a touchscreen, but the standard five-button set up you find on almost all Garmin running watches makes it easy to navigate the menus and control the device during training sessions.

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Turn the 945 over and you see the main design difference with the 935, which is the updated heart rate monitor. Along with usual green lights you see for optical heart rate, there’s a red light for the new PulseOx sensor.

The all-black design of the Forerunner 945 isn’t as flashy as the Fenix 5 Plus or Marq Athlete watches, but its smart enough to wear everywhere, and it’s certainly comfortable enough that you’ll never feel the need to take it off aside from when it needs charging.

Garmin Forerunner 945: Sports tracking and training features

Unless you take a very niche line in sporting activities, the 945 will track any activity you care to do while wearing it. Naturally running, cycling and swimming are recorded in greater detail, but there are also modes for kayaking, cross-country skiing, yoga and countless others, including a gym mode, which automatically identifies the exercise you’re doing and counts your reps, with a reasonable degree of success.

Outdoor exercise is where the Forerunner 945 really comes into its own, and we're going to focus on running in this review, but we also also used it for cycling plus some indoor workouts like yoga and strength sessions. The 945 uses GPS, GLONASS and Galilieo satellites to accurately track your routes and ensure you’re not waiting long at the start of a run for it to lock on. We never had to stand around longer than 30 seconds for a signal to lock on. The roll call of other sensors is extensive and includes a barometric altimeter for extra accuracy in tracking activities in the mountains, and the Pulse Ox sensor to measure blood oxygen saturation.

If all of those sensors don’t satisfy, you can also link the 945 to ANT+ and Bluetooth devices, including bike power meters and a running footpod, which will allow to 945 to display live feedback on your running technique including stats like ground contact time.

More useful still is the new training load analysis, which doesn’t just tally up your overall workload and tell you whether it’s productive, but also breaks down your last four weeks of training into three zones – anaerobic, aerobic high and aerobic low – and gives you a target range for each.

Broadly these three zones translate to short, sharp interval workouts – anaerobic, steady to hard efforts – high aerobic, and easy runs – low aerobic. For your training to be as productive as possible, you need a mix of three, and the 945’s simple training load widget shows if you have attained the right balance.

I have a running coach and trust him absolutely to create the right balance with my training, so we were keen to see how the 945 rated our training. The watch had us down as productive, but detected that although overall training load was optimal, I could use some more anaerobic work.

As it happens, this rating was during a spell where I was racing a 10K most weeks with my club, so had reduced my track work to stay fresh for those. I’m going give the 945 credit here as say its overall analysis lined up quite closely with what I was doing. I’d definitely say that this more in-depth look at your training load is more useful than the rating of your overall load provided by the 935 and Fenix 5 Plus.

The 945 also rates each workout you do by its anaerobic and aerobic effect, estimates your VO2 max, and even give predicted race times. Interestingly the latter, which have always been wildly optimistic on past Garmins I’ve used, are now overly pessimistic. That might be something to do with the fact that these predictions are now based on historical training data, which wasn't the case in its first iteration.

Another new feature on the 945 is the heat and altitude acclimation measurement. These are activated when the temperature is over 22°C or the altitude is over 800m, and can be checked on the training status widget on the watch. Training in flat, wet north London we found this new feature less useful than the training load analysis, but they’d be handy for those heading to high elevations or hot climates for training camps.

The Forerunner 945 also links up to Garmin Coach, a new feature in Garmin Connect which sets up training plans for events ranging from 5K to a half marathon and beams them over to the watch to follow workouts on your wrist. Garmin Coach is smart and well implemented, but it’s aimed more at beginner runners we'd say, and anyone buying the 945 will probably have little use for it.

All in all, the sports tracking on the 945 is as good as anything available today. It’s accurate, unrivalled in its depth, and provides useful analysis in an engaging way that you can use to shape your training. Unless you fancy spending over on the Marq Athlete, this is the watch you should get if top-notch sports tracking is your priority.

Garmin Forerunner 945: HR accuracy

One major advantage that the Forerunner 945 has compared to Garmin’s more premium watches is that its light and slim build means it’s easier to get the secure fit required for accurate optical heart rate tracking. Since heart rate feeds into all of the training analysis mentioned above, this is crucial.

The 945 uses Garmin’s next generation Elevate heart rate sensor and during our month or so with the device every run with it has passed the smell test, in that the heart rate has been more or less what we'd expect it to be. However, when compared to a MyZone MZ-3 chest strap monitor linked to the Fenix 5 Plus it matched up very closely throughout a steady run, but did lag when it came to some short sprints we threw in at the end of the session. Not so much that you can really see it on the heart rate graph after the workout, but during the run we could see the 945 was three to four seconds behind the Fenix in responding to the change in heart rate.

Heart rate accuracy compared: Forerunner 945 (left) and chest strap (right)

The optical heart rate tracking on the 945 is certainly accurate enough for most of your everyday training, in that it will have you in the correct heart rate zone at least, and most likely be within a beat or two of a chest strap on steady runs.

We'd still be tempted to link it to a chest strap for interval or tempo workouts for maximum accuracy, but the 945 is as good as any wrist monitor we’ve tried. It was far more accurate for than the Suunto 9 and Polar Vantage V, for example, and a little better than the Fenix 5 Plus too.

Garmin Forerunner 945: Navigation

While the 935 offered breadcrumb navigation and a back to start pointer you could activate during a run, the 945 has full color maps and the ability to create routes on the fly, whether that’s to guide you back to the start of your run or to a point of interest.

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The maps are impressive and the route guidance is well done, with notifications when you’re off course and automatic zooming in and out to help you find the right way. We found that having maps rather than that breadcrumb trail came in handy on runs where a simple line isn’t enough to identify which way to go. Having a map showing all the paths including the correct one make it easy to see the way.

You can also create a round-trip course on the watch by choosing the overall distance and direction you want to go, which is a quick way to create a route when in a new place. We found these routes weren’t particularly inspiring in general, often sticking to bigger roads, so we'd rather take a little more time to map one out ourselves and send it to the watch, which you can now do in the Garmin Connect app rather than needing to use the website.

When following a preset course the 945 will also display how much climbing you have left to do, which is especially useful for cyclists and trail runners, along with the overall distance remaining and an estimated arrival time.

All of these features are the same as you get with the Fenix 5 Plus range, and they put both the Forerunner 945 and those watches well ahead of the competition from other companies when it comes to navigation.

Garmin Forerunner 945: Activity and sleep tracking

The Forerunner 945 is undoubtedly a sports-focussed watch but that doesn’t mean it’s lacking when it comes to everyday activity tracking. All the standard stats are there – steps, floors climbed, active minutes and the like – and it will even automatically adjust your step goal in line with how active you are.

You also get Garmin’s Body Battery feature, which provides a snapshot of your overall energy levels out of 100 and takes into account your activity and sleep, and 24/7 stress tracking based on heart rate variability. You can also track your blood oxygen saturation levels at all times using the PulseOx sensor, though this does impact on battery life.

The 945 will also use the PulseOx sensor for more detailed sleep tracking and it has the potential to be able to identify problems like step apnea. The automatic sleep tracking on the 945 can identify whether you’re in light, deep or REM sleep, and monitors your movement throughout the night as well as your blood oxygen saturation levels.

Unfortunately we didn’t find it was all that accurate, with awake periods often being logged as light sleep. Having just had a kid so I was up a lot in the night, and many of these awake periods were put down as light sleep, elevating total sleep time to numbers we’d love to say were true, but were highly optimistic.

Garmin has also recently introduced menstrual cycle tracking to Garmin Connect, and you can download a Connect IQ app to the 945 for this. It’s not something we could test ourselves, but it ensures Garmin keeps pace with the likes of Fitbit and Apple, who have also brought period tracking to their wearables.

Garmin Forerunner 945: Music and smartwatch features

The 945 is compatible with Garmin's Connect IQ store to add additional watch faces, apps, data fields and widgets. You also get the same notification support that is rolled out on other Garmin watches. That notification support might not be as polished as it is on an Apple Watch or Samsung smartwatch, but it's going to more than acceptable for most.

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The addition of music to the 945 is another major upgrade compared the 935, but it’s fair to say it was an entirely expected update, given that Garmin has been adding music to all of its new sports watches bar the budget Forerunner 45.

You can plug the 945 in to your computer to transfer across your favourite running playlists and podcasts, but the process is far easier if you have a premium account with a supported streaming service like Spotify, which will allow you to wirelessly update the music on your watch.

Once the music is on the watch you can access it at any time by holding down the bottom left button. It’s easy to control and pairing Bluetooth headphones seemed simpler and more reliable to than it did when Garmin first introduced music to its watches with the Forerunner 645 Music.

Since the music feature is now common across all Garmin watches it’s easy to be a little blasé about it. However, there was one run where we turned on a playlist while following a map around the forest and it really brought home how impressive this watch is – it really does do everything.

Everything, that is, except make NFC payments easy. Garmin Pay is still short of supported high street banks, with Santander the only one available. You can work around this using the Boon app or by signing up with a supported bank like Starling, but Garmin Pay is still not in the same league as something like Apple Pay.

The Forerunner 945 also has Garmin’s new Assistance and Incident Detection features. Set these up in Garmin Connect and you’ll be able to notify up to three contacts via both text and email in an emergency by holding down the top left button. It’s a smart feature and worth setting up immediately, even if the hope is you never have cause to use it.

Garmin Forerunner 945: Battery life

When the Fenix 5 Plus added features like music and maps across the range it resulted in a slight drop in overall battery life compared to the Fenix 5, so we were pleased to see this wasn’t the case with the Forerunner 945.

In GPS mode it will last 36 hours, a big jump from the 24 hours of the 935, and even if you have music playing with the GPS running it lasts 10 hours. That’s a bigger battery than the Fenix 5 Plus (18 hours of GPS, eight of GPS and music) and the Marq Athlete (28 hours of GPS, nine of GPS and music), for those keeping score. There’s also the UltraTrac mode, which sacrifices some GPS accuracy to extend the battery life to up to 60 hours.

In the real world we found that the Forerunner 945 would last about a week of training if regularly using the music and maps features and running every day. If we didn’t use the music at all then the battery life was more like 10 days. A one hour run where we played music and used the maps drained the battery by around 15%, while a 90 minute run without either maps or music took off 8%.

It’s a big battery, and it’s another key factor that would make us opt for the Forerunner 945 over the Fenix 5 Plus if you’re looking to pick between the two.