Wrist-based HR vs Chest Strap

[Frosty]

Last week I took the plunge a decided to buy the Garmin Forerunner 735XT (watch only, no chest strap). I just couldn't justify the extra cost for a Fenix 3, let alone the additional cost for the newly launched Fenix 3 HR.

I have previously used devices in the Forerunner range, and this latest purchase seems to continue in this trend. The reviews by Ray Maker (dcrainmaker website) gives most of the information, so there's no point reviewing what he has already done. Instead, I will give first hand experience over the next few weeks as I put this device through it's paces.

Thanks to the HealthyGear program through Discovery, I managed to knock R1K off the retail price of R7500, so it's still a hefty price to pay for a watch. But let me not think of it that way - it's more than just a watch. The sales person told me the blue strap is a girl's watch - but it will go nicely with a pending purchase (more about that in the future) - plain black is boring, and what other people think of me, is none of my business.

First Check - pairing Ant+ devices
The first check was to see if my own straps, speed/cadence sensor, and other Ant+ devices could connect (power meter added in September 2016). YES! The cost of the tri-bundle is R10K at Sportman's warehouse. R2.5K for a strap.

• Cycleops speed/cadence sensor - connected
• Powercal HR/Power strap - connected, will be up for sale.
• Garmin Forerunner 310XT strap - connected
• 4iiii Power meter (left side only) - connected

Second Check - Chest Strap vs Wrist-based
Last night, I deleted all paired straps from the 735XT to prevent it automatically connecting to a strap.
At the same time, I used my 310XT and the strap (paired) to get a comparison of HR between strap and wrist.

Below is the graph, plotted in Excel, using the 1s reading from both devices at the same time. I tried smoothing the line, but it doesn't make much difference whether ticked or not. The workout was a 45-min endurance (Z2) workout (25 mins at 56-65% of FTP, 20 mins at 66-75% of FTP) with a 10-min WU and 10-minute CD. Total duration was 1:05:12 (from starting to stopping).

• Average HR was the same - 151bpm
• Max HR - 176bpm (optical sensor) vs 175 (chest strap)

I will continue to record the data the same way, spread over weekend club rides, to weekday intervals to get an average performance from both device types.

What I do like is the close-enough accuracy to forego wearing an HR strap, even though it doesn't really bother me.


Third Check - battery life
The device had 25% when I switched it on for the first time, and I played around with it on Saturday afternoon. I then put it on charge while setting up the device on Garmin Express - having to connect using the cable (provided) is a big disappointment, compared to the wireless connection of the 310XT.

I have worn the device every minute of the day, except for shower time and two take two photos (one posted in the Boast about your latest purchase thread, and the photo showing the battery % as of 15:07 today (5 days after the last charge). Will edit the post to add the photo.




As you can see, the device has 36% left after 5 days of use. Included was 2 workouts (1:15 and 1:05), some bed aerobics , plenty notifications (whatsapp, emails, phone calls, tapatalk, SMS and more), and also setting up the profile for each bike/trainer - more than once.

I'm not too concerned about the steps taken, but I do find the reminder to move gets me away of the desk more often than I was previously doing. Not a bad thing, I guess.

I am satisfied that this device gives me everything I need, and the battery life is great. I haven't tested it (yet) using GPS mode, or the GPS/GLONASS mode - an update will be posted later.

Final Verdict - positive
While I like the Fenix 3 with HR, I just couldn't justify the cost, and at R7500 (less my Discovery discount), I still think this is expensive. It won't replace the 310XT on my bike, as it is mounted on the stem using the special mounting bracket. Having to turn my arm to read the info is a schlep I remember from my Polar days.

Another nice thing is the ability to screen my phone calls without having to remove the phone from my back pocket - although I don't think it works like the Apple Watch (speaking into the watch). Previously, on a ride I wouldn't even hear the phone ringing, so now I can see who is calling and decide if it's worth answering.

More posts to follow, once I've done some more testing.
If there is anything you'd like me to compare to... let me know, while I'm in "test" mode.
 

------------------------------------------------------------------------------------------------------------

Second round of feedback

Another update from this morning Active Recovery (Coffee ride), this time on the road for the first time and using normal GPS only (no GLONASS).

I forgot to check the battery % before leaving, but I do remember it was red in colour (below 30%). The battery level is currently at 10%, so let's assume 19% was used in this time.

Elevation - identical for each 1s recorded
The graph below shows the HR recorded on both devices with the elevation. The reason for putting the elevation into the graph was to show where the differences in HR data was recorded.

It's was a relatively flat route, 162m gain over 25.59Km (0.63% average), and I kept to the cadence I know keeps me in Z1. I may have hit Z2 for a bit early on, as I was running riding late to meet up with the others.



HR differences - mostly on uphills
There are 6 sections of the graph that shows a lag in the HR data on the uphills, and a slight lag during recovery of the flats/descents.

It's a bit early to be concerned, as this was primarily a ride to test the GPS for the first time, on a relatively short ride - no big efforts. This is the first bit that I have marked ORANGE (something to watch on later rides, and see if there are any flaws).

My next outdoor ride is only next week - Dad & girls weekend, while mom goes away on a weekend trip with her friends. Two endurance zone rides for me on the IDT while watching the final two stages of the Tour, so no use of the GPS for a while.

------------------------------------------------------------------------------------------------------------

Third update

Battery Charging - Quick, very quick
The battery required charging today, almost a week after putting on charge shortly after opening and testing the first few hours.

The devices shows the 24/7 heart rate (or at least the display is for the last 4 hours). The photo below shows the time it was off my wrist - 72 minutes to be more precise. That is a charge from 3% to 100%.



I'm not sure how that compares to the Edge range or the Fenix, but it is much quicker than the two prior Forerunners I've used.

[ScottCM]

In the DC review it states that the "special" HR-Run or Tri is required to be able to get the running dynamics such as Cadence, VOS etc including the Lactate threshold. 

 

As you rightly pointed out, paying an extra R3k for HRM straps when you are trying to get away from straps is counter productive, especially when you just want to monitor your LTH point as your fitness grows during a season. This is what put me off of the watch. 

 

However, yesterday when i went for my run, my 920XT didn't want to pick up my HRM for the 1st 10min or so, and when i went through my activity on GC i noticed all the running dynamics only start once the 920XT linked to the HRM. So seen as you don't have the R3k HRM can you please check if you do run whether or not it actualy gives this data or not?

[Frosty]

I have seen the VO2 Max, LT test and FTP tests where it mentions connecting a strap and the going for a 20-min (VO2max) 18-31 min (FTP) run/cycle.

 

I will do the VO2 Max test first, as the LT doesn't work unless the former has been done.

 

I'll be able to confirm the current Garmin strap works for these functions.

[Baaisikilist]

Well, in the greater scheme of things (this is how I justify purchases like these to myself anyway), as far as watches go, it's actually not that expensive. I mean, it has more functions relative to your interests, than buying say, a TAG or Rolex, for considerably more money, and those just look nice and tell time accurately, plus your mates think you're the shiz.

[Frosty]

Moved the info from this post into first post.

Second round of feedback.

[Cheese]

I know it is not in the same league, but have the Apple Iwatch and have checked that against my Heartrate Cheststrap  on a few occasions, Also have the average at the same or only 1bpm differences.

 

Do not have graphs but checks during training and they were always in line, with big effortsi a slight lag.

 

Can not use it for pacing purpose though on a bike as you do not want to move your wrist every time. So for a Bike I think the chest strap the best option.

[Schnavel]

The biggest difference I have found between using a wrist based monitor vs a strap can be seen when doing intervals.

 

The wrist based heart rate is delayed when doing intervals and heart rate strap picks up the changes.

 

For normal riding / indoor training, the wrist based and heart rate strap will give a similar result, within a beat or two. However, if you do some intervals where you spoke your heart rate, you will get a very different set of results.

[SwissVan]

Very interestIng topic, it must be lovely to be able to receive accurate / instant heart rate data without having the schleep involved with a strap.

 

Please keep us informed on the accuracy comparisons

[Andrew Steer]

I know not all wrist based hrm readers are made equal, but the Apple Watch one comes well short when it comes to more vigorous exercise... doesn't work well during squash (and other things like Crossfit, Inddor Soccer etc) from reports I have read. For normal running and riding though, it seems to work 100%. Just a heads up from my side. They are apparently working on it though 

[Frosty]

I have used my wife's Apple Watch I a similar way. It does record the HR at specific intervals and is viewable in the Health App but a schlep to put into a graph.

 

On an IDT the results were similar.

 

The objective of my posts are to give a first hand review of my experience of using an optical device vs chest strap.

 

Over time, I will add some non-bike related activities

[BigDL]

I keep tracking my Apple Watch heart rate during exercise against my wahoo strap connected to my garmin 520. They tend to be almost identical, however it would seem that wrist based hrm's will always be a challenge during some types of exercise because of the need to have constant contract with the skin.

 

 

Sent from my iPhone using Tapatalk

[Frosty]

In the DC review it states that the "special" HR-Run or Tri is required to be able to get the running dynamics such as Cadence, VOS etc including the Lactate threshold.

 

As you rightly pointed out, paying an extra R3k for HRM straps when you are trying to get away from straps is counter productive, especially when you just want to monitor your LTH point as your fitness grows during a season. This is what put me off of the watch.

 

However, yesterday when i went for my run, my 920XT didn't want to pick up my HRM for the 1st 10min or so, and when i went through my activity on GC i noticed all the running dynamics only start once the 920XT linked to the HRM. So seen as you don't have the R3k HRM can you please check if you do run whether or not it actualy gives this data or not?

I'm on the IDT tomorrow so I can test the link between the cadence and speed sensors to the device, as well as using my existing strap to do the VO2max test. This would be to see if it works without the Run/Tri strap.

[Underachiever]

Hi Gerald

 

Please do a comp. for MTBking too.  I believe the wrist based measurement is poor due to the shaking involved.

[Hennie VR]

Hi Gerald

 

Please do a comp. for MTBking too.  I believe the wrist based measurement is poor due to the shaking involved.

 

I also wonder if there will be a difference when one goes running.

 

I am also thinking about a watch with the wrist based HRM for running purposes but don't want to invest the money if the readings are way different.

 

Will appreciate it if you can give a review on running as well some time. I don't like wearing watches during the day so if I buy a watch it will only be for running purposes.  

[shaper]

I use a mio wrist HRM with my fenix 3, works good for running, have not compared accuracy with a chest strap, but as am using the same wrist HRM for all runs then it is at least consistant http://www.mioglobal.co.za/product/mio-link/

 

Don't enjoy a chest HRM when running long distance

[ScottCM]

I'm on the IDT tomorrow so I can test the link between the cadence and speed sensors to the device, as well as using my existing strap to do the VO2max test. This would be to see if it works without the Run/Tri strap.

 

My old strap that i use quiet happily gives me the Cadence, VOS & VO2Max on the 920XT. I would however like to know if by using the old strap on the 735XT it can give you the LTH, and if using no strap at all, can the watch still give you cadence while running.