Garmin Forerunner 945 Multisport GPS Watch Review


Basic summary: An update to Garmin’s premium multisport GPS watch that features enhanced battery life as well as extensive new training and physiological metrics, safety features, and music playback.

Deep dive:
This spring, Garmin introduced a new lineup of five new Forerunner (FR) GPS watches. Each model kept existing features of its predecessor, and added features first introduced on higher-priced models. The Forerunner 945 is an update to the Forerunner 935, which had been our watch of choice for the past couple of years. We’ve used the 945 through a full training and racing season this spring and summer.

In the case of the Forerunner 945, it retains virtually all the features of the 935, but also incorporates almost all of the functionality of the Fenix 5 Plus, as well as some key physiological metrics from the ultra-high-end MARQ series. It has a price point that is $100 higher than the initial FR935 MSRP, but from our standpoint, the added features justify the price, especially for what is perhaps the most important item you’ll use every day for several years.

Perhaps the most impressive thing about all of the updates to the FR945 is that it has not changed in size, weight, or fit of the FR935 in any way. The new watch is significantly more powerful, in a virtually identical container. This is an important consideration for those of us who wear the watch all day long – even in work settings – because the FR945 has a low enough profile to wear under dress clothes, and is light enough to not feel cumbersome when worn casually, or even with pajamas. Six months ago, the Fenix 5 had a more robust feature set, but its size made it too cumbersome to wear as a 24-hour tracker. Now, the FR945 has all of the Fenix 5 features (plus some from the MARQ), with the slim and comfortable fit we loved in the FR935.

Large numbers, easily visible data

Smart Watch Capacity
Some of the new FR945 features help Garmin keep pace with high end smart watches from Apple or Fitbit, such as the capacity for digital payments. Music storage and playback is another huge upgrade, and allows you to store MP3 files directly from your computer or access downloaded playlists from third party services like Spotify and listen through Bluetooth-connected headphones. You can control playback through the watch, even during activity through a separate screen you can scroll to, but from a practical standpoint we didn’t find it to offer a huge advantage over controlling playback from your phone – especially because loading playlists onto the watch proved to be quite time consuming.

Ultrarunning Specifics
For ultrarunning purposes, the key improvements of the 945 fall into three categories listed below in increasing order of impressiveness:

  1. The ability to download color street maps and topo maps, and access them in real time during your run
  2. Incident detection and automatic contact notification in case of emergency
  3. A ton of new physiological metrics and analysis

Let’s go through these in order. A couple of years ago, downloadable color maps was a super big deal; now, just like with music, it’s way easier to handle with your phone and most apps work effectively on airplane mode in the backcountry, so keeping maps on your wrist is more of a last resort contingency. Garmin’s own Earthmate app is a much more user-friendly option, as are numerous other trail apps. But it’s still worth noting that this was a hallmark feature of the Fenix 5 series and is now standard on the FR945.

Emergency Notification
Incident detection is one of those things you’ll hopefully never use, but if you ever have to, buying this watch will be the smartest thing you ever did. This technology was first introduced in cycling devices, and uses the watch’s accelerometer and gyroscope to determine if your activity has come to a sudden and possibly dangerous stop, like getting hit by a car or falling off a cliff. Prior to using the watch, you identify an emergency contact in the Garmin Connect app. When an incident is detected and you need assistance from your device, Connect uses its LiveTrack function to send your name and location to your emergency contacts, along with a real-time feed of your location during the activity. We inadvertently triggered this once after a hard fall going downhill; the watch displays a prompt asking if you’d like to notify your emergency contact; luckily, we were able to select “no.”

Physiological Upgrades
This leaves us with the physiological metrics, which are significantly augmented compared to the FR935. Most interesting for mountain runners is the addition of pulse oximetry, which tells you the percentage of oxygen in your blood. Unfortunately, this is only possible at rest, so the prospect of checking your saturation as you’re climbing a peak in real time isn’t possible – but it does give you a sense of acclimation if you are staying at high altitude for a length of time. And if you happen to be training for Western States or Badwater, the FR945 can also tell you how well you are becoming heat adapted over a period of time.

Other training analytics monitor your performance and generate personalized feedback over a specified period, and many of the time periods can be customized from one week to several months. The FR945 tracks your VO2 max and adjusts the value based on heat and altitude. Training status evaluates your recent exercise sessions to indicate if you’re training productively, peaking or overreaching; this seems highly dependent on intensity, as approaching your max HR (such as in a track workout) is the quickest way to improve your overall status. After each workout, you see a recovery recommendation for the time you should wait before your next hard effort. An overall training load screen consolidates your exercise volume and intensity from the past seven days and compares it to the optimal range for your fitness and recent training history.

Body Battery
The most intriguing aspects of the physiologic metrics are your real-time stress level and body battery, which is new on the FR945. Initially these were hard to distinguish, but with prolonged use, the distinction becomes clear. Cardiac stress is a real-time measurement taken at regular intervals throughout the day, while body battery is a comprehensive feature that combines heart rate variability, stress, and recent activity to estimate your energy reserves throughout the day. It tends to peak after sleep or a rest day, and bottoms out after a hard effort or poor night’s sleep. In our training, the body battery was eerily accurate in its predictive value, in that whenever we started a run with a low body battery level (less than 40% or so), it seemed like we had a lousy run. We learned that this was a great indicator to take an extra rest day if we woke up and our body battery was still low.

Overall Function
A GPS watch is one of the most significant gear investments ultrarunners will make. For the money involved, you want to be certain you’re purchasing something both durable and highly functional. Garmin devices are traditionally very dependable and user-friendly, even with the richest feature profiles in the category. In our testing, the Forerunner 945 looks to be a worthy successor to the high-end multi-sport line, providing all the metrics you could ever ask for in a manner that’s easy to manage, comprehend, and most importantly, guide and enhance your training.

The Garmin Forerunner 945 is now available at as well as multiple retailers.

MSRP: $599


  • Weight: 50g/1.76 oz
  • Dimensions (mm): 47 x 47 x 13.7
  • Display size: 30.4mm diameter
  • Display resolution: 240 x 240 pixels, multi-color
  • Lens material: Corning Gorilla Glass DX
  • Battery life:
    • 2 weeks in smartwatch mode
    • 10 hours in GPS mode with music
    • 36 hours in GPS mode with wrist-based HR
  • Water rating: 5ATM
  • Multiple alarm and alert capacity
  • Silent/vibrating alerts
  • 24/7 continuous HR monitoring with Elevate Optical HR sensor
  • Continuous pulse oximeter (not functional during activity)
  • Sleep tracking and advanced metrics
  • Music storage up to 1000 songs and external playlists
  • Music playback controls at wrist
  • Contactless NFC payments

Training and Navigation

  • GPS tracking through GLONASS and Galileo systems
  • Downloadable topo and street maps with wrist navigation
  • Barometric altimeter
  • Compass, gyroscope, accelerometer, thermometer
  • Altitude and heat acclimation
  • Incident detection for emergency notification
  • ClimbPro for real-time climb details during activity
  • Training load, stress tracking, and body battery
  • Fitness age
  • Four data screens available during an activity
  • Multiple screen customization options


  • Functionality through Garmin Connect app or desktop
  • Data screens customized at wrist or through app
  • Connect IQ downloadable watch faces, data fields, widgets, apps
  • Automatic data transfer to Strava and other third party apps
  • Phone and text notifications and response through watch during activity (Android only) and at rest
  • Garmin Pay compatible
  • Connects with Garmin inReach Mini (sold separately) for wrist-based operation

About Author

Donald is a physical therapist, California native, barefoot aficionado, and father of three with more than 25 years of experience in endurance sports. He was a collegiate rower at UCLA, then dabbled in marathons and Ironman-distance triathlons before falling in love with ultras in the early 2000s. His favorite locations to run include Marin County, CA, and the Sierra Nevada mountains, and he loves exploring America's National Parks. When he's not training for ultramarathons, he enjoys hiking or slacklining with his family in Monterey County, CA.

1 Comment

  1. Terry Smithers on

    Interesting review – Thank you.
    I have used the Garmin Forerunner 935 for around six months and purchased the Garmin Forerunner 945 as a replacement mainly for the music, pay and maps functionality. I have used the Garmin Forerunner 945 for around three months now.
    In the real world, I have not used the anticipated functionalities for the following reasons:
    a) Music – Getting music on is problematic. The music that is on there is on more by luck than understanding. I still have not used this fully even though I have some music on there, I cannot work out how to get more music and podcasts on. For example, I have some running music. Despite having spent hours trying to get this music on, I cannot seem to do it.
    b) Pay functionality – The merchants and processors that support this in the UK are few. I had to get a credit card from Santander just to use this functionality. After all of the hassle of getting the credit card, I just cannot be bothered with having to manage another specific credit card just for this so do not use it.
    c) Maps – The maps are not the ones that I want to use. However, having the map functionality is appreciated and I probably will use it eventually although I use alternative technology to provide this for OS explorer mapping.
    d) Pulse OX – The Pulse Ox is way off. My Pulse Ox dips to below 90%-85% frequently. For those that know, anything below 95% is of concern. Using this 945 Forerunner, my results means that I should be getting some extra oxygen somehow and I certainly should be breathless etc. Instead, I am running sub-hour 10k. My partner who is a nurse and uses Pulse Ox equipment says that the results are way out.
    e) Battery life – The battery life is significantly less than the Forerunner 935 especially when the Pulse Ox is in use. Since the Pulse Ox is nowhere near enough accurate, I have turned it off completely. This has saved some of the battery usage but it still does not last anywhere near as long as the Forerunner 935.
    f) Distance accuracy – This is causing me a problem at the moment as the 945 Forerunner seems to be significantly less accurate and not more accurate compared to the Forerunner 935. My distance accuracy is varying by as much as 20% extra. Obviously, this is causing me some difficulties when I am actually running as I cannot see the accurate distance. At home, I can later edit the distance and insert the actual distance run.
    All-in-all, upgrading from the 935 Forerunner was a mistake. However, I am pleased to support Garmin nonetheless as they are making real efforts to improve this technology.