Garmin Forerunner 235

These days we expect running watches to be more than distance and pace trackers. Increasingly, we want them to coach us too, with insights on how to improve form and train smarter.

It’s why the latest devices offer ever-more-detailed running dynamics, heart rate analysis and training feedback. It’s why you’d also think that a watch launched more than two years ago might struggle to keep up.

However, thanks to some future-proof tech at launch and subsequent updates the Garmin Forerunner 235 does just that. Despite its age it’s still a viable choice for runners with a keen eye for performance and a bargain.

Let’s be straight, there are more feature-rich watches out there, the Garmin Forerunner 645 for a start, which means the 235 isn’t even the best Garmin watch money can buy, but before you click away in a fit of early adopter haste, it’s worth giving the Forerunner 235 careful consideration, because this is a powerful lower-end watch with a lot going for it. Not least its price.

Garmin Forerunner 235 price and availability

Because of the Forerunner 235’s age you can pick it up much cheaper than its original £299.99 / $329.99 / AU$469 RRP. It came out around the world toward the end of 2015, so it's almost three years old now.

We’ve seen it drop a full hundred pounds below its original price in the UK, and if you shop around you'll likely find similar discounts in other countries, so if you’re looking for lots of run-tracking capability but on a budget, that should make it a very attractive option.

If you see it for under £160 in the UK, snap it up right away, because that's a really great deal for something that's still not been really replaced by Garmin and does a good job.

Design, comfort and usability

• Crisp color screen
• Comfortable silicone strap
• Heart rate sensor compromises comfort

Sport watches are rarely stylish and though the Forerunner 235 is still unmistakably a Garmin, it’s among the better-looking run trackers you can buy. It comes in three color combinations: black and frost blue, black and red and black and grey, and there’s some smart subtlety to the latter two.

There’s a classic round-faced, 1.23-inch diameter color screen that’s crisp and easy to read in most light, with enough real estate to display up to four stats on two customizable screens.

If you’re a fan of touchscreens then the lack of one here might disappoint, instead you get five side buttons to navigate your way through Garmin’s relatively simple menus.

The perforated soft silicone strap makes for a more comfortable, less sweaty run, particularly useful over longer distances and considering you’ll need to wear this a little tighter on the wrist to get the best accuracy from the built-in optical heart rate sensor.

That said, comfort is compromised somewhere thanks to the fact the Forerunner 235’s sensor protrudes more than you’ll find on the likes of the Polar M430 and it can dig in a little on longer runs.

The buttons are responsive and easy enough to use on the move though and the whole thing weighs in at just 42g, which makes it one of the lighter watches you can strap on, though some people might not like the overall plastic feel that’s clearly helped shave off some grams.

Heart rate

• Useful 24/7 heart rate tracking
• Suspect VO2 Max scores

The Garmin Forerunner 235 tracks heart rate (HR) from the wrist, though you can also pair ANT+ chest straps if you prefer the accuracy this brings. 

It was one of the earlier devices to eschew the Mio optical heart rate sensors in favor of Garmin Elevate sensor technology.

We put the 235 to the test up against the Polar M430 over a range of sessions, including a marathon distance.

As you can see from the graph, the devices performed fairly consistently. Garmin (bottom graph) clocked the average HR at 154bpm and Max HR at 179bpm while the Polar M430 registered a 154bpm average but a Max HR of 172bpm. Anecdotally during the run the Polar seemed to run at 3-4bpm lower than the Garmin.

Both devices offer resting heart rate (RHR) tracking and when we came to compare them, both gave identical readings but the way Garmin highlights this hugely useful benchmark for health and fitness is much better.

In fact, the continuous 24/7 heart rate tracking on the Forerunner 235 is one of the best we’ve seen for monitoring your progress and spotting things like potential over-training and incoming colds.

With the touch of a button you get a read out of your current heart rate, highs and lows, your average RHR and a visual showing the last 4 hours. You can then tap for a chart of your RHR over the last 7 days. 

Resting heart rate high that morning? That’s a sign you might want to skip a training session or ease off the intensity, and the Forerunner 235 makes that a much easier decision.

The Forerunner 235’s optical heart rate sensor also powers a VO2 Max reading, or the maximum volume of oxygen you can use, measured in milliliters per kilogram of body weight per minute (ml/kg/min). It’s another great indicator of your current fitness levels and progress.

Usually done in a lab test, watches, such as the Forerunner 235, increasingly boast estimated VO2 Max scores. Without stepping into a lab it’s hard to assess the accuracy but when we compared the Polar M430’s score with the Forerunner 235, it’s clear that someone’s got it wrong.

Polar estimated our VO2 Max at 69, just one point shy of what Runner’s World could classify as an elite result. Garmin, in contrast, has us at 51 which is somewhere between sedentary 35-year-old and average 35-year-old. That’s a stark contrast and the truth is we’re probably somewhere in between.

Many running watches we've tested haven't been on the money with this metric, but as long as it's consistent you can use it as a sign that you're getting fitter - which is far more important to many.

Run tracking and running metrics

• GPS locks on quickly
• Accuracy seems reasonable but not perfect

There are four sport modes: Run, Run Indoor, Cycle and Other, and it’s really useful that you can customize two data screens with up to four fields to create your own preferred displays for each of these.

Indoor runs are tracked by the on-board accelerometer while GLONASS and GPS provide the usual outdoor pace, distance and speed metrics. In our treadmill test the Garmin was within 5% on total distance, though unsurprisingly the pacing rarely matched the treadmill’s.

Outdoors we consistently got a rapid GPS fix, though when it came to accuracy there were some question marks. For example, on our marathon test, running an officially measured course, the Forerunner 235 clocked our distance at 41.96km, short of the 42.195km.

That’s not far out but in our experience running watches tend to come up longer rather than shorter over a marathon once they’ve taken a bit of weaving into account.

In addition to distance, time, pace and calories, during your run you can also see cadence, heart rate and heart rate zone and there are customizable audio and vibrating alerts to help guide you on target pace and heart rate.

You can store up to 200 hours of activity on the watch itself giving you plenty of scope should you wish to dig for insights from your past runs from the wrist, though with instant updates via your smartphone’s Bluetooth to Garmin Connect you might not need that.

Activity

• Tracks your steps and distance all day
• Shows how active you've been at a glance

The Forerunner 235 isn’t just a running watch, it’s also a comprehensive activity tracker that learns your daily patterns and automatically sets you step goals to strive for.

The main screen features an inactivity bar that creeps around the watch face when you’re on your backside, plus the accelerometer will keep tabs on your overall step count and distance covered during the day. 

All of which you can access with two taps of the left-hand arrow button to take you to a display.

If you're into that sort of thing, it's a great extra feature to have, and you can even join leaderboards of other Garmin users to try and out-step them in a single day.

Warning: this can become addictive.

Smart training, recovery and sleep

• Race Predictor seems unreliable
• Sleep tracking skills are lacking

Tracking what you do when you’re training is one thing but there’s more to improving performance than just run session stats. 

Being able to see the impact of your training run, predict recovery time and do things to recover quicker are all really useful and the Forerunner 235 offers a good set of features for just this.

Post run you get what Garmin calls Training Effort, a heart rate-based assessment of the overall training impact of your run. Scored on a scale from 0-5 it’s designed to tell you whether your session had an improving effect on your fitness.

Then there’s the Recovery Advisor that tells you how long it’ll take to recover from your most recent effort. There’s a Race Predictor feature too that uses all of your data to estimate how quickly you could run a 5k, 10k, half and full marathon.

However, in practice we question how reliable this is as a true guide. Having just struggled to run a marathon in 3:59, it feels unlikely that the predicted time of 3:15 is accurate. Conversely, we’re pretty sure we can run 5km quicker than the 20.24 estimate.

Sleep also features, with the Forerunner 235 offering some assessment of the quality of your pillow time. However, when we tested it against the Polar M430 there were quite significant discrepancies.

Garmin had us asleep at 9:38pm (we were on the sofa but not asleep) while Polar correctly recognized we actually fell asleep an hour later. Overall -
according to Garmin - we had nearly 12 hours of sleep compared to Polar’s 8 hours 46 minutes.

In general, Garmin’s sleep tracking has a way to go before it matches up to Polar, which offers up things like sleep efficiency totals, accurately captured sleep interruptions and is starting to turn sleep tracking into a genuinely useful training insight.

Garmin Connect and Connect IQ

• Automatic syncing is great... when it works
• Packed full of features but can feel overcomplicated

Big brands' apps and web platforms divide opinion. Some people love Garmin Connect and hate Polar Flow, others take the opposite view. Others hate them both. Whatever your view, Garmin has worked hard to make Connect a more capable partner.

There are some really nice touches, such as the fact that if you’re already a Garmin user, Connect will auto update your personal information for your new watch so you don’t have to re-input your height, weight and everything else.

We really liked the fact you can create a training calendar and sync that to the Forerunner 235, letting you see from your watch what your session is for the day, even down to the length of your warm up. 

We also like the fact that sessions can be synced straight into Strava so you can still boss your local leaderboards.

Automatic smartphone syncing over Bluetooth is another fantastic time saver, when it works. However, we found that wasn’t all the time and frequently had to re-pair our Forerunner 235 with our phone to update our stats when using an Android phone, although in our experience Garmin watches are far more stable with an iPhone.

Sadly, this watch also doesn't offer Wi-Fi like some of the more expensive models... that would have been a nice touch but explains how the cost can be lower.

With Garmin’s ‘app platform’ Connect IQ you also get access to loads of downloadable watch faces, data fields, widgets and apps so you can further customize your 235 to meet your needs.

However, as new features are added there’s a real danger that Connect is becoming a complicated beast that makes it harder to pull insights from your data, though the app is far simpler than the web tools for reviewing runs.

Smartwatch skills

• Allows notifications and music controls
• Shows full messages, not just subject lines

To add to its all-rounder credentials, the Forerunner 235 packs in a range of smartwatch skills including smart notifications for calls, emails, messages and social media updates, plus Spotify and music player controls, and audio announcements, all of course provided you run with your phone.

It’s an added bonus that you can read your messages rather than just get the subject line and also that you can easily set Do Not Disturb to cut out the pestering should you want to run uninterrupted.

Battery life and charging

• Enough battery to last an average week
• Proprietary charger is an annoyance

When it comes to endurance, Garmin claims the Forerunner 235 can last up to 9 days in watch mode and up to 11 hours in GPS mode with the heart rate monitor in use.

We tested it over a normal training week starting on Sunday with a long 1.5 hour run, with three short midweek runs of up to an hour and then normal daily usage in between. It coped with all of that but we put it back on the dock before the following week’s Sunday run.

We also gave it a whirl on a marathon, taking it off the dock at 6.30am on race day. It had no trouble tracking a 4-hour marathon and made it through to Wednesday with normal activity tracking and smartphone notifications on before it finally died.

It’s more than capable of coping with an average training week, and it could potentially handle a 100km ultra for faster runners.

Like all Garmins, the Forerunner 235 comes with its own special charging cable and all the frustrations that brings for traveling and not being able to charge it easily on the move unless you remember to bring your special lead with you.

Anything else I should know?

There’s a stopwatch, an alarm clock, automatic daylight saving updates, calendar sync, weather information and a nifty little Find My Phone feature, though Find My Watch might be more useful.

Who’s it for and should I buy it?

The Garmin Forerunner 235 delivers enough training insights to satisfy runners at most levels, right up to those shooting for personal bests at the faster end of the pack.

It’s probably a tool for those who take performance at least semi-seriously more than casual fitness runners, as there are cheaper options for those who really only want to know how far, fast and hard they’ve worked.

The 11-hour battery life could potentially make it suitable for faster ultra runners tackling runs up to 100km, but its skills are more suited to tarmac than trail.

A bit like Steve Winwood’s back catalog, the Forerunner 235 has aged well. This is a fantastic running tool that’s still very competitive. In fact, if you don’t care about some of the more complex running dynamics we’re seeing offered on newer models such as the Garmin Forerunner 645, then this should definitely be on your Amazon price alert list.

First reviewed: September 2017

Competition

Not sure about the Garmin Forerunner 235? Instead you may want one of these other watches.

Polar M430

The Polar M430 is an upgrade to the best-selling M400 and looks almost identical until you flip it over to find a built-in heart rate sensor. It's a good upgrade too, keeping all of the features that made the M400 so popular but bringing some extra intelligence too. 

In addition to solid wrist-based heart rate tracking, there's better GPS, improved sleep tracking and smartphone notifications. It all adds up to one of the best mid-range running watches to buy right now. It's also more future-proofed than the Forerunner 235. 

• Read the full Polar M430 review

TomTom Spark 3 Cardio + Music

TomTom’s wrist-based heart rate tracking tool also offers GPS tracking for multi sport and 24/7 activity tracking, but where it differs from the Forerunner 235 and is the ability to store up to 500 songs locally on the watch, meaning you can whack on a pair of Bluetooth headphones and run phone-free.

The web tools aren’t anywhere near as advanced as Garmin Connect or Polar Flow, but this is a strong alternative if you love running with music but hate bringing your smartphone.

• Read our full TomTom Spark 3 review

Or other Garmins...

Garmin's extended family of run trackers is growing all the time and the US giants offer something for runners of all abilities. But how do you know which one is the perfect running partner for you? We've tested them all and built our findings into a handy guide to give you the topline on the best Garmins you can buy right now.