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Inaccurate HR readings from FR 235. Compared to chest strap with Polar M400.

Former Member over 9 years ago

I will get to the point;

The 235, after the first run, showed in my opinion elevated HR overall by about 10 bpm.

Next day I put on my 235 and also M400 by Polar with chest strapped HR monitor.

It appears that 235 is simply lagging. When I suddenly start my exercise, the M400 is spot on while 235 will take 10-25 seconds on average to catch up to the real HR.

Same with slowing down, where your heart is really recovering, my M400 will hit 70 while 235 will be still at 110 until it eventually catches up.

Is there any other solution to this than buying a chest monitor for 235?

I cant wear them all the time as they irritate me (Polar at least does). I think I will be forced to use chest one with 235 until I start getting irritated and then switching to next best thing - the wrist measurements.

Any other ideas?

0 chunkywizard over 9 years ago

Make sure you are wearing the 235 tight enough to leave an impression on the skin and also slightly further up the arm than you normally wear a watch. Saying all that, optical heart rate isn't perfect and is slightly laggy (not brilliant for intervals) but it should be better than you are seeing.

HTH

CW

0 Former Member over 9 years ago

Yeah, I will try it a bit tighter tonight (going for a run soon). I do 30-45 min run on track so its mostly steady pace, thats why the concern. I ordered the strap today too for use until I get irritated, then back to optical I guess and back and forth.

0 Former Member over 9 years ago

Ok, so today after I strapped the watch tighter (and it was snug last time) the HR values seemed same as the Polar M400 chest monitor and I used both today at the sam time. Results - identical.

The only difference I saw was with the speed, Polar watch was showing .2 to .3 MPH higher than 235. It wasn't updates (the GPS) on polar in some time though so I will give benefit of doubt to 235 on that.

But yeah, the 235 has to sit really very tight on wrist without any wiggle room whatsoever in order to yield good results. At the last lap (I think) it spiked up by like 10pts as it loosened a tiny bit. After moving it "up" the wrist, it stabilized.

I only wonder, why would it go up (the HR) on the watch when it loosened rather than drop down..weird.

Anyway, here are the results for today (you can see yesterday numbers for HR were up by 10pts)..

I had one issue before run though - the watch was not showing HR at all in the running mode so I restarted it to fix that. Is that happening sometimes..?

Link: https://connect.garmin.com/modern/activity/1143478920/share/0?lang=en

0 R_Tellis over 9 years ago

It is, at times, taking longer to lock on to HR when starting an activity for me.

What I've taken to doing is bringing up the HR widget as I head out the door of my apartment so that it's getting that lock as I'm going down the stairs so that it's ready to go as soon as the GPS signal locks on.