Garmin Forerunner 45/45S GPS Watch In-Depth Review


On one hand, the Forerunner 45 represents Garmin’s most capable running watch they’ve ever made below $200. On the other hand, it tries to counter the wave of Apple and Samsung products at or flirting with $199 price points as well – all of which are immensely more capable everyday watches, complete with music, contactless payments and plenty more.

So how does Garmin compete? By trying to absolutely nail the sport side of the equation. To that narrow and very specific goal, the company bests Apple or Samsung (or Fitbit). If you’re looking for a running or sport specific watch, then continue reading. If however, you’re looking for more of a lifestyle watch – then honestly other offerings out there that have far better non-sport features. As such, I’ve never been more conflicted about the pricing of a given watch than on this unit. But more on all that later, we’re getting ahead of ourselves.

The Forerunner 45 brings to the sub-$200 price point the ability to download structured workouts, including those from the company’s free ‘Garmin Coach’ adaptive/dynamic training programs, as well as incident detection and assistance (which notifies friends/family if you get into trouble). It adds has an optical HR sensor on it for tracking 24×7 HR and stress, though no PulseOx like the FR245 and above.  It supports more than just running, with other sports including cycling treadmills, and yoga, but doesn’t have quite the number of sports their other units have.  And finally, it adds Connect IQ custom watch faces, but stops short of allowing full Connect IQ apps or data fields.

Now this wasn’t the only device released today. In fact, Garmin released two others units: The higher end Forerunner 945 triathlon-focused unit and mid-range running focused Forerunner 245/245 Music. Atop that, Garmin also announced new female health tracking – and it’s actually impressive how much effort they put into it, so check that out too a bit later today.

In the case of all these devices, I’ve got standard media loaner units that’ll go back shortly. After which I’ll go out and get my own via normal retail channels. Just the way I roll. If you found this review useful, you can help support the site via the links at the bottom. With that, let’s begin!

What’s New:


To begin, I’ve got a complete rundown of all the new goodness and one easy to consume less video. Approximately one coffee cups worth. Or at least, European coffee cup sizes. If you’re Runnin’ on Dunkin with a 24oz, then I’d suggest you supplement this video with my Forerunner 245 video as well (if nothing else because the intro is kinda cool). For everyone else, start with the Forerunner 45 video:

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Of course – if straight to the bullet point facts are more your thing, then hit up below for my attempt at outlining all the newness is one consolidated list.  Note that this is specifically in comparison to the older Garmin Forerunner 35, which is basically what this watch grew up from. Of course, that watch was also $30 cheaper, so…yeah.  In any case, here’s what’s new/changed relative to that:

– Added two sizes: 39mm (Forerunner 45S) and 42mm (Forerunner 45)
– Added color display
– Added structured workout support
– Added training plans support (including calendar/scheduled workouts)
– Added Garmin Coach compatibility
– Added Connect IQ Watch Face support
– Added incident (crash/fall) detection
– Added safety tracking/assistance
– Added Pace/Speed alerts
– Added stress widget/tracking
– Added VO2Max calculation
– Added 24×7 HR tracking widget/tracking
– Added body battery widget/tracking
– Added new Garmin Gen3 ELEVATE optical HR sensor
– Added Bluetooth Smart sensor support (HR/Speed-Cadence/Footpod)
– Added more sport modes
– Changed from square watch to round watch
– Changed from 4 to 5 buttons (which actually makes a world of difference)
– Changed all-day battery from 9 days down to 7 days
– Of note: GPS-on battery life remains same at 13 hours (GPS-mode)

Now if you’re not familiar with the Garmin Forerunner family at this price point, here’s the two-second version of what else you’ve got in it:

– Built-in GPS (no reliance on phone for GPS)
– Workout support for a few sports, with customizable pages/fields
– 24×7 activity tracking, including sleep
– Optical heart rate sensor in watch
– Smartphone notifications
– Live tracking when paired with a smartphone
– Weather/calendar widgets
– Vibration/Audio alerts
– Uploading to Garmin Connect Training Log website via phone or USB
– Broadcasting of your HR over ANT+ (from wrist to other devices)
– Automatic sync to 3rd party sites like Strava, MyFitnessPal, TrainingPeaks and many more

The Forerunner 45 is seen as Garmin’s least expensive running watch, at least, least expensive new one. They’ve also got the Forerunner 35 in there – which removes all the things I outlined in the first chunk up above. Garmin says they’ll be keeping that around for a while – mainly because it hits a lower price point.  Though I expect we’ll see the Forerunner 35 probably drop in price more quickly over the coming months, as Garmin will likely aim to attract buyers at the $100-$139 price point that they’ve largely vacated with current products (it used to be the FR25 that fit in there).

In any case, this section was all about the new goodness, so now it’s time to dive into the basic operation of the watch itself.

The Basics:


Probably the biggest difference between the new Forerunner 45/45S and the Forerunner 35 is the basics of the device. While the interface of the Forerunner 35 was roughly based on past budget Garmin watches, the new FR45 instead follows the menu system of Garmin’s higher end watches. Which, in my opinion makes it a heck of a lot easier to use. Note that anytime I refer to the FR45, I’m referring to both FR45 and FR45S. They’re technologically identical in every way except the bezel is simply larger on the FR45 (not the screen size, just the bezel). Below you can see the four flavors, with the two 42mm ones on the left, and the two 39mm ones on the right.



Speaking of that screen, you’ll find that default watch face looking at you once you’ve gone through the quick start configuration. You can toggle between a couple of different stock watch faces. Though unlike Garmin’s higher end units, you can’t customize the stock watch faces (changing data and such). You can only tweak the accent color.




The good news though is that you can download thousands of custom watch faces from Garmin Connect IQ store, which is Garmin’s free app store. Heck, you can even make your own watch faces – including adding in photos as the background. The world is your oyster, or at least, the watch face portion of the world.

The FR45 captures all the normal activity tracking metrics you’d expect, including steps (as well as distance), sleep, and heart rate. It doesn’t capture stairs however, as it lacks a barometric altimeter to measure height. These metrics are consolidated into widgets, which you can iterate through on the watch quickly by pressing the up/down buttons. Note that the FR45 doesn’t support downloading Connect IQ Widgets like some of Garmin’s higher end watches, but there’s plenty of stock ones to choose from on the watch itself. Here’s a gallery of some of those.


While the watch is tracking your activity constantly, its also sending that over to Garmin Connect Mobile (the smartphone app) via Bluetooth Smart. From there you can view these activity stats, challenge friends/family, and also see the states on the Garmin Connect website. In addition, some 3rd party sites and healthcare providers can also receive this data if you’ve authorized them to.

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The unit will also automatically track sleep data if you wear it at night. Technically you can set your regular sleep timeframe to any portion of the day, though it will only track one ‘sleep’ per day. Meaning – it doesn’t track naps.  In my experience it does a pretty good job of nailing my sleep, even with having toddlers running around and waking us at all sorts of random hours. The unit will track the exact sleep cycle, and then log it into Garmin Connect. You can plot and trend this over various timeframes.

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The Forerunner 45 benefits from a new optical HR sensor ‘package’, the same exact package as the Forerunner 245/945/MARQ. This is used to track your heart rate 24×7, as well as during workouts. For heart rate, it includes modest updates over the sensors used about a year ago, though a bit more significant update over the much older Forerunner 35 sensors.  Note that while the sensor hardware itself on the FR45 to that of the other new units noted, it doesn’t have PulseOx enabled.


From a continuous heart rate standpoint, it tracks this constantly and then uploads it into Garmin Connect mobile as well. I use resting HR as a great indicator of when you’re over-trained, fatigued, or when sickness is on the way. I’ve discussed how many people tracking resting HR and 24×7 HR data to figure out all sorts of things here.

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In general I don’t really have any issues with the accuracy of the 24×7 HR data. It’s pretty much within a few BPM of any other devices I’ve used, including some dedicated sensors. We’ll talk more about the workout optical HR data later on though, as that’s in a different category (and typically vendors significantly bump up the optical sensor light/power draw during a workout versus in 24x7mode).

Back on some of the basics, the Forerunner 45 supports smartphone notifications like all previous Garmin watches. You’ll see the notifications per however you’ve configured them on your smartphone via the normal phone notification center, and then they show up on the unit itself. You can then open up a given notification to get more detail about it (such as a longer text message):




You can also check missed/past notifications in the notifications widget seen in the widget gallery a bit earlier in this section. Note that unlike the higher end Forerunner watches, the FR45 doesn’t support a privacy mode for smartphone notifications. Perhaps because the screen is so small that people across the conference table are unlikely to read your texts anyway.

With that, let’s shift over to all the sporty goodness you bought this watch for.

Sport Usage:


The Forerunner 45 is all about being a sport watch, or at least, a running-specific watch. Sure, it does other stuff – including cycling and yoga. But realistically you’re buying it for running (or perhaps walking). As I said at the beginning, there are better and more full-featured devices at this price point for other sports (and if you’re OK with something a bit chunkier, then the Polar M430 is more full featured at the same price).

To begin with sports, you do indeed have a few options when it comes to which sports are on the device. By default, that’s: Running (outdoors), Treadmill, Cycling (outdoors), Walk, and Cardio (catch-all bucket).

However, you can use the Garmin Connect Mobile app to add other sports, which include: Indoor Track, Bike Indoor, Walk Indoor, Elliptical, Stair Stepper, Yoga, and the mythical ‘Other’. You can have a max of 6 activities loaded onto the watch at any one point in time. In other words, they duplicated what Fitbit does here (for no particularly good reason).

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No matter whether you’ve modified the sports or just kept with the defaults, to start recording a new workout you’ll simply tap the upper right button and then select the sport:


Once you’ve done that it’ll ask you if you want to execute any scheduled workouts for that day. So if you had something loaded up from Garmin Coach for example, or something else on your calendar, it’ll offer those to you first (which you can skip).

After that you’re at the GPS and HR waiting screen. It’s here that it’ll go off and find GPS. This Sony GPS chipset supports GPS, GPS+GLONASS, and GPS+Galileo.


As part of this, the unit will also ensure it has lock on your heart rate via the optical HR sensor on the back of the unit. Generally that’s instantaneous since it’s constantly tracking HR 24×7 anyway.

If you press down again before you start the workout you can tweak some of the settings for that sport, in this case – running. First is the ability to select a structured workout. While before it asked us if we wanted to do the day’s scheduled workout, if you had nothing scheduled/setup – then this is a chance to select one from your library of workouts. Or, you can just do a one-off interval session where you define the duration of the interval, the repeats, the rest, and the cool-down/warm-up.






Next, you can customize your data screens during the workout. The FR45 is pretty basic, mirroring that of the FR30/35 before it. Here’s what you get to start with (all are three-field pages by default). All of these are customizable:

Data Page 1: Distance, Timer, Pace
Data Page 2: HR Zone, Heart Rate, Calories
Data Page 3: Lap Time, Lap Distance, Lap Pace
Data Page 4: Time of day clock page
Data Page 5 (Optional): 1, 2, or 3 metrics each of your choosing
Available Data Metrics: Timer, Distance, Pace, Calories, Heart Rate, HR Zone, Lap Time, Lap Distance, Lap Pace, Average Pace, Cadence, Steps, Time of Day.

In the case of cycling, you’ll get the speed variants of each of the above (I.e. MPH/KPH) instead of pace. You can’t add any more than the 5 pages seen above, but again, you can tweak what’s on those pages to suit your liking.  Also, you can long-hold the lower left button to access music controls, which controls the music on your phone if nearby (there’s no music on the watch itself).

Next, you can configure alerts. Options include heart rate (zone, or custom BPM range), run/walk (time based), time, distance, pace (specific pace), or calories.


What’s nice is that you can configure alerts, but toggle them on/off quickly to use on different runs. For example you might setup run/walk for your long run, but then toggle it off for your other runs that week. It’s a single toggle, versus having to set it up again.

Next, you can configure laps. By default auto-lap is enabled at 1-mile (or 1-kilometer depending on if you use statute or metric). But you can manually lap at any time with the lap key. Or you can turn auto-lap off.


Finally, there’s auto pause, which is off by default, but can be enabled to automatically pause the timer when you stop. Unlike some of Garmin’s higher end watches though – there’s no configurable threshold on this though. Also, the GPS options are in here as well, where you can toggle between the aforementioned GPS modes (GPS/GLONASS/GALILEO).

Oh, and while not in this menu, you can pair three different sensor types to the Forerunner 35: External HR straps, Cycling Speed/Cadence Sensor, and Running Footpods. This supports both ANT+ & Bluetooth Smart sensor types:


With all that setup done, we’re ready to press start on our run and get cookin’. Once we’ve done that we’ll see the data pages and the unit is recording. Here’s a small gallery of what those screens look like:


In the event you’re running a structured workout, then you’ll also get a new workout target screen, which shows the specific targets of your workout. In my case, I made a workout on Garmin Connect Mobile prior to this run. Here’s what it looked like:

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Then, while running it’ll give me a 5-second beeping countdown to each segment of the workout, followed by the specific targets for that portion. It’ll also give me a little guide chart while doing that section with the target, as well as the specific time/distance/etc remaining for that portion.

Sorry, it was darker than I thought out, but the text says: ‘Run 0.25mi 5:45-6:15/mi’ – just like it does above in the programmed instructions.

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It works well and is easy to follow.  And in many ways, this tiny tidbit is the most important part of this watch. It’s what fundamentally separates it from the Apple Watch and others which lack the depth and customization of the structured workout program.  For example, while I did the above workout as a manual one-off, I did it with numerous steps and complexity that’s just not possible on Fitbit, Apple, or Samsung watches with default apps. Sure, you can go off and find 3rd party apps on Apple or Samsung to roughly emulate that, but not inbox.

Inline with that, Garmin has their Garmin Coach program, which is free. This allows you to specify a given goal (currently up to a half-marathon race), a specific race date, and then a specific race pace (up to 7:00/mile – 4:21/KM). From there it’ll come up with a race plan for you. However, this actually isn’t pre-canned (well, not entirely):

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See, you have to do a test workout first (it’s only 9 minutes), and then based on the results of that test workout, it’ll fill in exactly what the structure and intensity is to reach your goal time.  You can just which days of the week you can workout, and your preference for the long run too.

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I haven’t followed a full plan – mostly because (prepare for humble brag) the fastest allowable race pace isn’t fast enough for that I need. However, this is far beyond what we’re seeing from any other manufacturer for free.  Sure there are companies doing this for pay, but even then, it’s frankly not much (if any) different than this.

In any case, back to our run. Once you’re done you’ll go ahead and press the start button to pause it. At this juncture you can eat some ice cream and then press resume to continue running, or, you can end it for realz.

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Once ended you’ll get a little summary page, including your current VO2Max level:

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You can also review some very basic totals and laps too. This is far more basic than most other Garmin watches show, but it gets the job done:




A few seconds later, the watch is automatically transmitting this information over to your phone via Bluetooth Smart.  It’s there that you can see much more detailed information on Garmin Connect Mobile (the smartphone app):


Note above that it actually overlays the specified paces against the actual paces from the workout. Kinda neat.

Additionally you can also look at your workouts on the Garmin Connect website as well, for example, this workout here of mine (link if you want to toy around a bit):


Further, if you’ve connected Strava, MyFitnessPal, TrainingPeaks or any other sites, all of those will receive a copy of your workout instantly as well. Just remember on Strava to add emoji, it increases your likes (so they say).

The one last thing I want to touch on in the sports section is Garmin’s Incident Detection and Assistance features, which are seeing widespread rollout to Garmin devices – especially with these three (FR45/245/945) product launches. Both features are safety focused and have two slightly different purposes:

Incident Detection: This will automatically detect an incident while running/cycling (in a workout specifically), and notifies your predefined contacts with a text message and a live track link to see exactly where you are.

Safety Assistance: This allows someone to with one button send a predefined message to emergency contacts with your initial location, followed by a live tracking link. The main scenario here being you feel unsafe and want someone to be aware of that.

Both of these features depend on you having your phone with you. Since the Forerunner 45 doesn’t have cellular in it, you need to be within range of your phone. Both features can be cancelled in the event they’re triggered accidentally. And both features are setup on Garmin Connect Mobile first. It’s here you define emergency contacts:

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Once that’s done, the crash detection will occur while cycling or running during a workout. This is different than Apple, which has fall detection 24×7.  Essentially, Garmin is looking for forward speed, followed by a significant stopping accelerometer event – and then critically – no further forward progress. Meaning, if you were running along and jumped down a big ledge and kept running, that wouldn’t trigger it, since you continued going. Whereas if you were running, jumped off the ledge and then face-planted, that would likely trigger it since you ceased making forward progress.

Meanwhile, here’s what the safety assistance feature looks like, when you trigger it (which is done via long-holding the upper left button, or via the rotary menu):


From a cancellation standpoint – both the assistance and incident detection features act the same way. And in many ways, once triggered, the results are more or less the same – just different wording on both. Here’s what the person on the other end receives:

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In both cases, Garmin isn’t notifying emergency services. Instead, they’re notifying your predefined emergency contacts – aka your friends/family/etc. So be sure to pick people who actually want you saved. Just a thought.

Rounding things out – the thing that makes the Forerunner 45 a more capable running watch than the Apple Watch or Samsung Galaxy Active (or Fitbit Versa/Ionic) is the structured workout and complete tie-in with all of the aspects of Garmin Connect/Garmin Connect Mobile. In the case of Samsung and Apple, both platforms are really more about showing off a single workout – than about tying in an entire seasons worth of data.  The same is true of Fitbit, which is great at the social aspect of activity tracking, but less so the details of workouts. Atop all that, some people just like buttons when they’re trying to do a hard workout and don’t want to fumble with a touch screen or gloves on a rainy and cold winter day. In that scenario – Garmin delivers buttons – five of them.

GPS Accuracy:


There’s likely no topic that stirs as much discussion and passion as GPS accuracy.  A watch could fall apart and give you dire electrical shocks while doing so, but if it shows you on the wrong side of the road?  Oh hell no, bring on the fury of the internet!

GPS accuracy can be looked at in a number of different ways, but I prefer to look at it using a number of devices in real-world scenarios across a vast number of activities.  I use 2-6 other devices at once, trying to get a clear picture of how a given set of devices handles conditions on a certain day.  Conditions include everything from tree/building cover to weather.

Over the years I’ve continued to tweak my GPS testing methodology.  For example, I try to not place two units next to each other on my wrists, as that can impact signal. If I do so, I’ll put a thin fabric spacer of about 1”/3cm between them (I didn’t do that on any of my Forerunner 45 workouts).  But often I’ll simply carry other units by the straps, or attach them to the shoulder straps of my hydration backpack.  Plus, wearing multiple watches on the same wrist is well known to impact optical HR accuracy. One technique I’ve been using a bit starting this review that’s worked exceedingly well is below. How on earth I never thought to place the secondary watches on the outside of my hands (loosely strapped) is beyond me. Note, for those units on my hands, they *are not* using optical HR. Instead, they’re connected to chest straps and other HR sensors.


Next, as noted, I use just my daily training routes.  Using a single route over and over again isn’t really indicative of real-world conditions, it’s just indicative of one trail.  The workouts you see here are just my normal daily workouts.  In addition, in a rare special appearance my wife also ran numerous workouts with the Forerunner 45 as well, testing it out with 2-3 other watches and HR sensors concurrently. I’ve included some of her data in there.

All of the workouts you see here I did with GPS+GLONASS enabled, as Garmin noted that’s the mode they’ve spent the most time on the GPS performance on. They said they haven’t spent as much time on Galileo. However, in my testing of the older FR935 with Galileo, I’ve seen mind-bogglingly good results in the last two months since the bulk of the Galileo constellation went live back in February. Even in places like NYC it’s thrown down some tracks that some of you on Strava have been like ‘Who dis? Holy crap.’. In any case though, for the FR945/FR245/FR45 watches, I kept them all on GLONASS for the bulk of my testing (I did try some Galileo runs/rides and saw less accuracy than with GLONASS).

In any case, let’s start off with an interval run from a few nights ago. In the case the route starts off near some buildings along the canal, and then slowly opens up, though it does have tree cover the majority of the way. It wouldn’t be considered difficult, but sorta suburban normal. The watches on this run are the Forerunner 935, Polar Vantage V, Suunto Trainer Wrist HR, Garmin Forerunner 245 Music, and Forerunner 45. Here’s the data set:


It’s a clear out and back. I don’t usually like out and back workouts, because it makes it harder to spot GPS errors, but in this case I think we’re going to luck out. At the high level, things look fine. Still, I see a couple of moments of separation in the track, so let’s go ahead and zoom in:


For the most part, the units are within 2-4 meters of the path (which is covered in trees with leaves now). Though the FR45 does seem to wander a bit on the outer edge of that realm.  Still, most would consider that nitpicking. More important is that they all handle the 19 car-train-plane-boat who knows what gigantic bridge underpass. They collectively nail it, nobody gets lost and plots a wonky GPS point on the other side.


Here’s a few brief moments where the Polar Vantage V and Suunto Trainer go for a dip in the lake. The trail edge is directly on the edge of the water, so any mistake is immediately aquatic in nature.


We see a few other minor course cuttings by the Polar/Suunto devices, but nothing major for the remainder of the track:


Overall both the FR245 and FR45 did well here – no issues of concern.

So let’s step it up – can they go around a track? Aside from the buildings of Dubai or NYC, it’s the hardest thing for a GPS unit to do properly. The constant turning nature of a track is incredibly difficult to nail perfectly, especially since an average workout might have 20-40 laps. Or, 20-40 opportunities for just one tiny screw-up to immediately be obvious.

In this case, The Girl is running with the watch (I’ve got another set, also on the track at the same time). Her lineup is the Fenix 5s (original), the Suunto Trainer Wrist HR, the Forerunner 945, and the Forerunner 45. Here’s that data set:


What’s fun about this game is that it’s immediately obvious who did well. The name of the game here is keeping yourself within the bounds of the track. The Suunto Trainer was well outside of that – something The Girl could see on her wrist just looking at distances as she ran. She placed her bets mid-way through the workout.

Here’s the results if we toggle to just the FR45 and FR945. Almost perfectly within the bounds of the track. In The Girl’s case, she was actually across multiple lanes, so that’s correct. As is the squiggly into the trees to get a errant soccer ball for some kids.


There’s really no reason to further analyze this one – both the FR945 and FR45 nailed it. Both were in GPS+GLONASS modes.

Let’s head back away from the track, but still keeping it on The Girl’s wrist. In this case she heads out along the lake towards…well…cows. To be fair, they’re usually friendly. Here’s the track file below comparing the FR245 on one wrist and FR45 on the other. The FR935 is used as a reference in this case.


Overall things are pretty good, but we do see a little bit more smoothing than I’d like to see on some of the turns. This could be partially because the FR45 only offers ‘smart recording’ which reduces the recording rate and can cause these sorts of issues. Note how the teal line meanders a bit delayed there. It may also just be that it’s slightly offset (still wrong though).


Still, once back in town along the canal and 3-5 story buildings, the unit does just fine:


Which is sorta the general gist of things. While the smart recording functionality has the potential to undercut some accuracy bits, overall there’s not a ton to complain about here with respect to GPS accuracy.

Note that all these tests were done with GPS+GLONASS, and not GPS+GALILEO. Garmin specifically noted that they’d spent more time on GPS+GLONASS than Galileo, and that at this point, that was there recommended configuration (and, what it’s set as the default). So, I left it there for now.

(Note: All of the charts in these accuracy portions were created using the DCR Analyzer tool.  It allows you to compare power meters/trainers, heart rate, cadence, speed/pace, GPS tracks and plenty more. You can use it as well for your own gadget comparisons, more details here.)

Heart Rate Accuracy:


Before we move on to the test results, note that optical HR sensor accuracy is rather varied from individual to individual.  Aspects such as skin color, hair density, and position can impact accuracy.  Position, and how the band is worn, are *the most important* pieces.  A unit with an optical HR sensor should be snug.  It doesn’t need to leave marks, but you shouldn’t be able to slide a finger under the band (at least during workouts).  You can wear it a tiny bit looser the rest of the day.

Ok, so in my testing, I simply use the watch throughout my usual workouts.  Those workouts include a wide variety of intensities and conditions, making them great for accuracy testing.  I’ve got steady runs, interval workouts on both bike and running, as well as tempo runs and rides, and so on.

For each test, I’m wearing additional devices, usually 3-4 in total, which capture data from other sensors.  Typically I’d wear a chest strap (usually the Garmin HRM-DUAL or Wahoo TICKR X), as well as another optical HR sensor watch on the other wrist (primarily the Polar OH1+ and Wahoo TICKR FIT, but also the Scosche 24 too).  Note that the numbers you see in the upper right corner are *not* the averages, but rather just the exact point my mouse is sitting over.  Note all this data is analyzed using the DCR Analyzer, details here.

Note that while I’ve been using the Forerunner 45 for a number of weeks now, I’m mostly going to use recent data in this review – since that’s the firmware that it’s currently on and the production firmware that real world people are using.

Let’s go ahead and start this optical HR festival with the same interval run from a few nights ago. I very specifically designed this to be hard on the optical HR sensor, including 400m and ~200m intervals, as well as build and rest phases to give the sensor as much of a workout as me. The comparison data includes a chest strap (HRM-DUAL), the TICKR-FIT, and then the Forerunner 245 and Forerunner 45. Here’s the data set:


Ok, to start off with – all of the units nailed the warm-up and build without issue. And in fact, the first two intervals seemed to go pretty well also. Everyone was happy up until that point.

However, as we got into the 400’s, you can see the FR245 struggle a bit on the recovery. It easily hits the actual work portion, but seems to stumble fully recovering. This is somewhat common for optical HR sensors, though not quite to the degree we see on the 2nd interval here. Still, overall this actually isn’t horrible. And the FR45 handled it just fine.


Next in that workout was the 200m sprints. The Forerunner 245 repeated the same inability to find the rest portions, though nailed the work portion each time (which is also somewhat unusual). Usually when optical HR sensors fail, they do so at the very high cadences of a sprint, not the much easier walking portion (these were all walking rests). We also see the FR45 struggle on these shorter recoveries as well. The other sensors have no meaningful issues here.


So let’s aim for something a bit tamer. So we’ll load up one of The Girl’s more steady-state workouts she did out and back along the lake. In this case her workout was slowly building intensity. We’ve got a chest strap (HRM-DUAL) paired to the FR935, while the FR245 and FR45 are one on each wrist. Here’s the data set:


Things actually look pretty close for her. We see a bit of a brief bobble by the FR245’s optical sensor at about the 1-minute marker. Though it trades places with the fumble, where the FR45 actually fumbles at the 31 minute marker during a brief walking section.


You can clearly see though that the FR245 in purple actually figure it out relatively quickly, and if you overlay the running pace/cadence it matches beautifully, whereas both the chest strap and FR45 stumbled here. So this seems to be a bit of a pattern, whereby during recoveries/rests the FR45 often misses the mark

Let’s head indoors for a moment then to a workout yesterday.  This one a 50 minute ride on Zwift. In this case we’ve got the Forerunner 45 on one wrist, and the FR945 on the other. Plus a HRM-DUAL chest strap and then a TICKR-FIT paired to Zwift. Here’s the data set.


Huh. Well, that first 7-8 minutes is more or less a car wreck. While I was riding, since I was riding Zwift I’m also using my hands to control things like interactions on the phone, though that was on the console in front of me – and those first 8 minutes I was mostly playing catch-up because I had jumped on a bit late for the race start and skipped a warm-up.


On the bright side, at least the Forerunner 45 did well there – which shares the exact same optical HR sensor package as the FR945 does. Goes to show that simply which wrist you’re on can make a difference. Both were tightened the same.

Ultimately, in looking at these and other data sets, the optical HR sensor seems to be a slight improvement on the Fenix 5 Plus series (which was the previous generation HR sensor prior to the current V3). I think there’s probably something to be said for Garmin’s approach here of just ever so slightly incrementally improving their optical HR sensor, rather than massive wholesale changes for each new products. In the case of optical HR sensor accuracy, it’s mostly a game of fixing 1% issues. Fixing an algorithm error that may cause an issue for 1% of the population, but if you do that 10 or 20 times, you start to make significant ground. Essentially the whole concept of marginal gains. Roughly.

Of course, you can still just have bad-day moments like my ride yesterday with the FR945. Win some, lose some.

Product Comparison Tool:

I’ve added the Forerunner 45 into the product comparison tool, which allows you to compare it against any watches I’ve reviewed to date.  For the purposes of the below table, I’ve compared it against the existing Fitbit Versa, Apple Watch Series 3 (often on sale for $199), as well as the Samsung Galaxy Watch Active.  But you can easily mix and match against any other products within the database here, by creating your own product comparison tables.  Note that in some cases nuanced features (like the specifics of how different watches track training load or recovery), doesn’t really fit well into product comparison tools designed to host hundreds of watches:

Function/Feature Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Copyright DC Rainmaker – Updated April 30th, 2019 @ 8:33 amNew Window
Price $199 $279/$379 (cellular) $199-$229 $169 $199
Product Announcement Date Apr 30th, 2019 Sept 12th, 2017 March 2018 Sept 1st, 2016 Feb 20th, 2019
Actual Availability/Shipping Date Early May 2019 Sept 22nd, 2017 April 2018 Sept 2016 Mar 9th, 2019
GPS Recording Functionality Yes Yes via phone Yes Yes
Data Transfer USB, Bluetooth Smart Bluetooth Smart Bluetooth Smart USB, Bluetooth Smart Bluetooth Smart
Waterproofing 50 meters 50m 50m 50 meters 50 meters
Battery Life (GPS) 13 Hours 5hrs GPS on time (24-48hrs standby) N/A Undeclared (claims 45hrs non-GPS)
Recording Interval SMART RECORDING (VARIABLE) Varies 1-second SMART RECORDING (VARIABLE) 1-second for GPS, 1-minute for HR
Satellite Pre-Loading via Computer Yes Yes (but seems questionable) N/A Yes Yes
Quick Satellite Reception Great Not generally N/A Great Yes
Alerts Sound/Visual/Vibrate Vibration/Audio/Visual Visual/Vibrate Sound/Visual/Vibrate Vibrate/Visual
Backlight Greatness Great Great Great Great Great
Ability to download custom apps to unit/device Watchfaces only Yes Yes No Yes
Acts as daily activity monitor (steps, etc…) Yes Yes Yes Yes YEs
Music Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Can control phone music Yes Yes Yes Yes Yes
Has music storage and playback No Yes Yes No Yes
Streaming Services No Apple Music, Spotify (but not offline yet) Pandora, Deezer Spotify
Payments Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Contactless-NFC Payments No Yes Yes (with certain editions) Yes (but only with Samsung phone)
Connectivity Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Bluetooth Legacy (pre-4.0) to Phone No No No No No
Bluetooth Smart (4.0+) to Phone Uploading Yes Yes Yes Yes Yes
Phone Notifications to unit (i.e. texts/calls/etc…) Yes Yes Yes Yes Yes
Live Tracking (streaming location to website) Yes With 3rd party apps No Yes No
Group tracking No No No No No
Emergency/SOS Message Notification (from watch to contacts) Yes (via phone) Yes No No No
Built-in cellular chip (no phone required) No Yes (with cellular version) No No No
Cycling Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Designed for cycling Yes Yes Yes Yes Yes
Power Meter Capable No No No No No
Speed/Cadence Sensor Capable Yes No No Yes No
Strava segments live on device No No No No No
Crash detection Yes No No No No
Running Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Designed for running Yes Yes Yes Yes Yes
Footpod Capable (For treadmills) YES (ALSO HAS INTERNAL ACCELEROMETER) With 3rd party apps No (but has treadmill functionality) YES (ALSO HAS INTERNAL ACCELEROMETER) With 3rd party apps
Running Dynamics (vertical oscillation, ground contact time, etc…) No No No No No
Running Power No No
VO2Max Estimation Yes Yes Yes, via app No No
Race Predictor No No No No No
Recovery Advisor no No No no No
Run/Walk Mode Yes With 3rd party apps No Yes With 3rd party apps
Swimming Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Openwater swimming mode N/A YEs No N/A Yes
Lap/Indoor Distance Tracking N/A Yes Yes N/A Yes
Record HR underwater N/A Yes No N/A Yes
Openwater Metrics (Stroke/etc.) N/A Basic stroke type only No N/A No
Indoor Metrics (Stroke/etc.) N/A Basic stroke type only Yes N/A Yes
Indoor Drill Mode N/A No No N/A No
Indoor auto-pause feature N/A Yes No N/A No
Change pool size N/A Yes Yes N/A Yes
Indoor Min/Max Pool Lengths N/A 1y/m to 1,500y/m+ 10m/y-100m/y N/A
Ability to customize data fields N/A Very limited Yes N/A
Can change yards to meters N/A Yes Yes N/A Yes
Captures per length data – indoors N/A Yes N/A Yes
Indoor Alerts N/A Yes (goals) Yes (distance) N/A No
Triathlon Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Designed for triathlon No Not really No No No
Multisport mode No Yes No No Sorta (can combine sports manually)
Workouts Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Create/Follow custom workouts Yes With 3rd party apps No (Premium Coached only) No No
On-unit interval Feature Yes With 3rd party apps No Yes No
Training Calendar Functionality Yes With 3rd party apps No No No
Functions Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Auto Start/Stop Yes Yes Yes Yes Yes
Virtual Partner Feature Virtual Pacer No No Virtual Pacer Pace guidance only
Virtual Racer Feature No No no No No
Records PR’s – Personal Records (diff than history) Yes No No Yes No
Day to day watch ability Yes Yes Yes Yes Yes
Hunting/Fishing/Ocean Data No No No No No
Tidal Tables (Tide Information) No No No No No
Jumpmaster mode (Parachuting) No No No No No
Geocaching No No No No No
Weather Display (live data) Yes Yes Yes Yes Yes
Navigate Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Follow GPS Track (Courses/Waypoints) No With 3rd party apps No No No
Markers/Waypoint Direction No With 3rd party apps No No No
Routable/Visual Maps (like car GPS) No With 3rd party apps No No No
Back to start No With 3rd party apps No No No
Impromptu Round Trip Route Creation No With 3rd party apps No No No
Download courses/routes from phone to unit No With 3rd party apps No No 3rd party apps
Sensors Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Altimeter Type No Barometric Barometric No Barometric
Compass Type None N/A N/A None N/A
Optical Heart Rate Sensor internally Yes Yes Yes Yes Yes
Pulse Oximetry (aka Pulse Ox) No No No
Heart Rate Strap Compatible Yes Yes No Yes 3rd Party Apps only
ANT+ Heart Rate Strap Capable Yes No No Yes No
ANT+ Speed/Cadence Capable Yes no No Yes No
ANT+ Footpod Capable Yes No No Yes No
ANT+ Power Meter Capable No No nO No no
ANT+ Weight Scale Capable No No nO No nO
ANT+ Fitness Equipment (Gym) No No nO No no
ANT+ Lighting Control No No nO No no
ANT+ Bike Radar Integration No No No No No
ANT+ Trainer Control (FE-C) No No No No No
ANT+ Remote Control No No No No No
ANT+ eBike Compatibility No No No No No
ANT+ Muscle Oxygen (i.e. Moxy/BSX) No No No No No
ANT+ Gear Shifting (i.e. SRAM ETAP) No No No No nO
Shimano Di2 Shifting No No No No No
Bluetooth Smart HR Strap Capable Yes Yes No No 3rd party apps only
Bluetooth Smart Speed/Cadence Capable Yes No No No No
Bluetooth Smart Footpod Capable Yes No No No 3rd party apps only
Bluetooth Smart Power Meter Capable No No No No No
Temp Recording (internal sensor) No No No No Yes
Temp Recording (external sensor) No No no No No
Compatible with Firstbeat HR tools No No No No No
Software Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
PC Application Garmin Express (PC/Mac) None PC/Mac Garmin Express (PC/Mac) No
Web Application Garmin Connect None YEs Garmin Connect No
Phone App iOS/Android iOS only iOS/Android/Windows iOS/Android iOS/Android (iOS is limited though)
Ability to Export Settings No No No No No
Purchase Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Amazon Link Link Link Link Link
Clever Training – Save a bunch with Clever Training VIP program Link N/A Link Link N/A
Clever Training – Save a bunch with Clever Training VIP program Link N/A Link N/A
DCRainmaker Garmin Forerunner 45/45S Apple Watch Series 3 Fitbit Versa Garmin Forerunner 35 Samsung Galaxy Active
Review Link Link Link Link Link Link

Remember, you can mix and match and create your own product comparison tables here, for watches not seen above.



There’s no question that Garmin packed an incredible number of features into the FR45, at least from an upgrade perspective over the FR35. Just like how the new FR245 stole features from once higher end watches, the FR45 effectively did the same from the FR235. Everything just slides down one notch, though, this model line also increased $30 in price over the previous edition – whereas the FR235 to FR245 didn’t cost any more (in fact, it went down). Still, if sports and fitness is what you’re after – then the FR45 is a super strong offering.

And so while I can’t really argue with any of the features/functionality of the FR45 by itself, I think in some ways Garmin is playing with fire at the $199 price point. As I noted earlier on, Apple has been toying with letting some larger retailers push the Apple Watch Series 3 down to $199 for short term sales. And it’s been doing so with increasing frequency as of late. It’s hard to imagine any scenario that doesn’t end up with Apple officially announcing the Series 3 being offered at $199 going forward from this fall as the baseline. While Garmin easily beats Apple in sports features, that’s a much tougher pitch when it comes to usage as a lifestyle watch. Of course, I’ve gotta believe Garmin designed this watch with significant margins to dramatically drop prices if situations require. And, at present it’s hard to argue with the reality that the company is selling more fitness and outdoors watches than ever before (of course, that doesn’t mean they aren’t losing more sales to Apple than ever before).

But like I said – today, in spring 2019 – there’s not much out there that has this level of sports/fitness integration except Polar, and in their case, they don’t pack the same features into as small a footprint watch-size wise than Garmin does. Which, for a lot of people is a key driver in the decision tree.

Found this review useful? Or just want a good deal? Here’s how:

Hopefully you found this review useful. At the end of the day, I’m an athlete just like you looking for the most detail possible on a new purchase – so my review is written from the standpoint of how I used the device. The reviews generally take a lot of hours to put together, so it’s a fair bit of work (and labor of love). As you probably noticed by looking below, I also take time to answer all the questions posted in the comments – and there’s quite a bit of detail in there as well. 

I’ve partnered with Clever Training to offer all DC Rainmaker readers exclusive benefits on all products purchased.  By joining the Clever Training VIP Program, you will earn 10% points on this item and 10% off (instantly) on thousands of other fitness products and accessories.  Points can be used on your very next purchase at Clever Training for anything site-wide.  You can read more about the details here.  By joining, you not only support the site (and all the work I do here) – but you also get to enjoy the significant partnership benefits that are just for DC Rainmaker readers.  And, since this item is more than $49, you get free 3-day (or less) US shipping as well.

Garmin Forerunner 45/45S
Garmin Forerunner 45/45S (EU/UK readers – don’t forget to use Europe coupon code DCR10BTF to save 10%)
Garmin Speed/Cadence Sensors (new ANT+/Bluetooth Smart ones – review here)
Garmin HRM-DUAL (new ANT+/Bluetooth HR strap – review here)

Additionally, you can also use Amazon to purchase the Forerunner 45 or accessories (though, no discount). Or, anything else you pick up on Amazon helps support the site as well (socks, laundry detergent, cowbells). If you’re outside the US, I’ve got links to all of the major individual country Amazon stores on the sidebar towards the top.

Thanks for reading! And as always, feel free to post comments or questions in the comments section below, I’ll be happy to try and answer them as quickly as possible.