Garmin Forerunner 235 Long Term Review

You can see the Forerunner 230 and 235 from the back. The 235 has the obvious wrist based Heart Rate Sensor.
Side by side looking at the back.

First off, the Garmin Forerunner 235 is a very impressive watch.  The testers at Athletic Tech Review (ATR) believe it is probably one of, if not the best running watches on the market right now.  It fits well, it works well (just a few bugs), and the wrist based heart rate tracking worked better than expected.  ATR won’t do a full review here like we did with the Forerunner 230 because the 230/235 do basically the same thing except heart rate.  You can read the full review with the Pro’s and Con’s of the 230/235 devices within our article Garmin Forerunner 230 Long Term Review.  In this article we are going to look specifically at the purchasing decision between the Forerunner 230/235 and how well Heart Rate tracking performed.

 

Our Testing

ATR tested this watch over a period of 5 months of running and indoor/outdoor bike riding.  The runner we used is a Marathon runner who was training for trail races and a half marathon at the time.  The trail races were a perfect opportunity to test the Forerunner 235’s wrist based heart rate tracking and accuracy.  There isn’t a more jostling environment than running up and down trails on rough terrain.  What we found was very impressive.

The Main Difference between the 230/235 is not just price, the batter life is a lot lower on the 235.
Forerunner 230 vs 235 Stats

Specifications

As you can see from the chart to the left, the only real differences here are price, and the battery life of the Forerunner 235.  The Forerunner 235 runs anywhere from 50 to 80 dollars more than the 230.  You can buy a good Heart Rate Strap like the ones from Wahoo Fitness for just under 60 dollars.  ATR finds chest measured heart rate to be the most accurate, but you will find further down in this article, that the 235 does a really good job.

The other thing to notice is battery life.  In our extensive testing of the Forerunner 230, we saw battery life up to 14 days with solid use.  The Forerunner 235 hit our benchmark of 7 days very well.  This means we are running about 10 to 15 miles a week and a recharge was easily done every 7 days.  ATR puts 7 days as the perfect recharge rate for any wearable device that tracks wrist based heart rate.  That means we charge it the same day every week and it makes things super easy to remember and build into your weekly routine.

Forerunner 230 vs Forerunner 235

Should you buy the Forerunner 230 or 235?  That is the question we asked ourselves when looking at our options.  The folks at ATR are always skeptical of wrist based HR tracking.  Many devices do a poor job of tracking HR on the wrist.  The Forerunner 235 is not one of those devices.  It is probably the best wrist based HR tracker on the market.  Should you spend the extra money and just get the Forerunner 235?  Yes, yes you should.  We were impressed and can show you an example below in the Heart Rate tracking section.  Just below are some pictures of the different screen looks on the Forerunner 235.

Heart Rate Tracking

The problem we have with testing devices that do wrist based heart rate tracking, is the inconsistencies the user gets at higher heart rate levels.  My marathon runner who tested out the Forerunner 235 for 5 months, has a Max HR in the upper 190’s.  This tester did a 8.7 mile trail race that had about 1,000 feet in total elevation.  Trail racers know how erratic and high heart rate can be in difficult races like this.  The Forerunner 235 had no problems with heart rate tracking, it is more about how you wear it.  Take a look at our full Heart Rate Tracking Review.

You can look at the race results below in the image gallery.  As you can see, the Forerunner 235 had no issues going up to, and tracking 197 beats per minute.  My tester stayed in zone 5 the entire race and the Forerunner 235 did an excellent job staying on track.  There were no dropouts of HR and tracking was consistent the entire time.  My marathon runner is now testing the Garmin Forerunner 630 (it’s in a weird spot right now) at the moment and has mentioned that the Garmin Forerunner 235 is sorely missed.  That is how well the heart rate function performed on the 235.

Indoor and Outdoor Cycling Use

It is easy to have the Garmin Forerunner 235 broadcast HR data as an ANT+ signal to indoor training Apps like The Sufferfest Training Centre or Zwift.
You can easily broadcast ANT+ HR data from the wrist.

You can also use the Garmin Forerunner 235 for cycling.  It will never replace my Garmin Edge 520 for outdoor cycling use.  You can’t pair a power meter, so that is a huge bummer.  However, you can transmit heart rate data from this watch.  That is a huge plus if you are cycling indoors.  The Forerunner 235 can transmit an ANT+ heart rate signal from your wrist.  This signal can be picked up by outdoor cycling computers or indoor training Apps.  I did use the transmit function with The Sufferfest Training Centre App and Zwift.  I only had one issue with HR tracking when on the bike.  I’ll talk about that more below when we look at the two annoying bugs with the Forerunner 235.

Broadcasting your wrist heart rate from the Forerunner 235 is fairly easy.  You just arrow down to the heart rate screen.  From there, you hold the up arrow on the screen until you get the broadcast option just like the picture to the right.  Select “Broadcast Heart Rate” and you will now send an ANT+ heart rate signal that can be picked up by other devices or apps.  It is really simple to setup and use.  This will drain some extra battery life.  I found that I lost about 5% to 10% battery life for a one hour cycling workout.  Not horrible, but it may affect your 7 day recharge cycle.

Bugs That Annoyed Us

There were two things with the 235 that really annoyed us.  One of them was not inherent with the Forerunner 230.  The watch crashed about once a month.  The good news is that the crash never happened on a run, nor did we lose the run workout when the 235 crashed.  The bad news is that we lost all of our step tracking from our last upload.  I’m sure the watch isn’t caching that data so it is retrievable like it does for a run workout.  Also, it took us a minute to figure out how to reset the time.  After the crash, the time would be incorrect and you needed to go into GPS mode for a few seconds for the watch to correct itself.

The second thing that bugged us was inaccurate heart rate tracking on the bike.  There is something that happens to the position of the watch and your wrist when you have your hand bent upwards.  Heart rate tracking becomes very unreliable when your hands are on the top of your bicycles handlebars and bent upwards.  We would see heart rate fall by about 20 beats per minute.  This means you can get some inaccuracies in HR reporting unless you are in the drops or stretched out over the hoods.  There was no effect to heart rate reporting in the drops or on the brake hoods.

Summary

We will be updating our Compare Equipment Page right now.  The Garmin Forerunner 235 is going to get some higher marks than its partner the 230.  We are in our first month reviewing the Garmin Forerunner 630, and we are already thinking the extra metrics and screen touch may not beat out the heart rate tracking that the 235 has.  My suggestion at the moment is to spend the extra money on the 235 and forgo the higher price of the 630.  If there was a Garmin Forerunner 635, then we might be saying something different.

ATR is a self run website that receives funding through purchases our readers make through our affiliate programs.  Did we help you make a decision in purchasing the Garmin Forerunner 230 0r the Garmin Forerunner 235?  Please click the links to purchase those watches.  We receive a small commission from your purchase and that helps us stay independent and advertisement free.

Coming in the future we will look at the Forerunner 630 (just as a benchmark, who knows what is happening with that watch), the Forerunner 935, and the Fenix 5S this summer.  Stay tuned and thanks for reading.

Aaron Johnson

Aaron Johnson

Aaron served in the military for 20 years. Multiple tours in Iraq and Afghanistan. He retired from the military after 20 years of service to take care of our three small children in 2013 as a Stay At Home Dad.

athletictechreview has 60 posts and counting.See all posts by athletictechreview

7 thoughts on “Garmin Forerunner 235 Long Term Review

  • May 16, 2017 at 1:30 pm
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    Great review – I already own a 235 and would agree about needing to use a chest strap when using on the bike outdoors, it moves too much to get a consistent reading for me. Indoors it’s not too bad
    I didn’t know it can broadcast my HR via ANT+ for Sufferfest, rather than using a chest strap, handy to know.
    Anyone used the live suffer score from Strava yet? I think you can also display this on the 235.

    Reply
  • May 17, 2017 at 12:36 pm
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    Hi, Did you compare it with the strap chest?

    Reply
    • May 17, 2017 at 12:54 pm
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      Hello Daniele,

      I did, but I just didn’t have the time to graph all the HR data out. The only trend I saw was it wasn’t as responsive as a chest strap. That means it was a few seconds behind in getting HR up to where the chest strap was reporting. This could be the watch also running a 3 second HR average possibly. The other issue was position of your hands and wrist when riding a bike. If you bent your wrists over the top of the handle bars, it would start to under report Heart Rate.

      Reply
      • May 17, 2017 at 1:14 pm
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        ah ok, la bici non è un problema, volevo sapere se la misurazione è precisa. se sbaglia di 3 – 4 bpm vs strap chest è ok ma 10, per esempio, sono troppi. Sto valutando l’acquisto di uno sportwatch con polso cuore preciso e spero che lo sia. grazie mille per la disponibilità!

        Reply
        • May 17, 2017 at 1:15 pm
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          Ah ok, bike is not a problem, I wanted to know if the measurement is accurate. If wrong of 3 to 4 bpm vs strap chest is ok but 10, for example, are too many. I’m considering buying a sportwatch with a precise heart wrist and I hope it is. Thank you very much for the availability!

          Reply
          • May 17, 2017 at 1:36 pm
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            It will never be as good as a chest strap, but this watch is the best I’ve tested yet.

  • May 18, 2017 at 1:02 pm
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    I am going to write an article this week about how variable the Wrist based Heart Rate can be. The 235 does a good job measuring Heart Rate at the wrist, but there are a few things you need to pay attention to. If the strap is loose, you will get high reports, or if you clench your fist when you run, then you will get low reports. I just ran with the 230, 235, and Vivosmart HR again and graphed it all out. In the beginning I kept the strap loose and then on a couple of intervals I clenched my fist to show the HR would not get up to where the 230 was at with the Chest Strap. I didn’t do anything with the Vivosmart HR besides wear it and it was not consistent at all. https://www.dropbox.com/s/k1pz7kphrw8xhyj/Screenshot%202017-05-18%2012.09.03.png?dl=0

    Reply

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