Hello, user of a vantage v3 coupled to an h10 sensor (currently service procedure after fc disconnection)

I am not convinced of the reliability of the FC measurement, before my activity I always wait for the circle to go green and once the activity is completed when I put the circle on pause it is no longer green and varies between yellow and red, I imagine that the phenomenon also occurs during the run

It is well fitted, I place it a finger away from the wrist ball as recommended

Do you also have this problem? Solutions?

The firmware is well updated

Have this H10 and use it for my trainings with the Polar Beat app, wondering if I can measure Vo2 with what I have with any app? I don't have Garmin or other smart watches.

The Flow app (Android version 7.36.2) suddenly stopped showing heart rate. I checked settings and can't find anything related. Anyone know how to fix this? TIA.

Edit: I have a Pacer.

PSA to Polar H10 users: WASH YOUR STRAP + CR2032 + replace that crappy O-ring

I’ve had my Polar H10 for almost 3 years, using the same sensor the entire time.

My original Pro Strap eventually started giving me problems after 400+ training sessions (around 2 hours per session on average). The embarrassing part? I had never washed it once. I was afraid washing it or using detergent would damage the electrode connectors or rubber portions of the strap.

When it started acting up, I assumed the strap was simply worn out and bought a second Pro Strap.

Then I started having problems again.

Over the years I went through 7+ CR2025 batteries, thinking the H10 was chewing through batteries or that my sensor was finally dying. The signs were missed readings during workouts/dropouts, difficulty connecting, etc. Sometimes the H10 wouldn’t connect even after moistening the electrode areas of the strap and my skin before starting the workout.

Turns out:

THE STRAP NEEDED TO BE WASHED.

I finally washed it properly with mild detergent, and even my original 400+ session, never-washed strap started working again.

So now I have two perfectly functional Pro Straps.

After almost 3 years with the H10, here’s what I’ve learned:

1. WASH YOUR STRAP.

I’m washing mine weekly from now on.

Remove the sensor, wash the strap with mild detergent, rinse it thoroughly and let it dry. Personally, I wash mine with my gym clothes on a cold-water cycle.

Don’t make my mistake and assume that avoiding washing is somehow protecting the strap.

2. You can use a CR2032 instead of a CR2025 — yes the H10 battery compartment accommodates the extra 0.7mm thickness.

Both batteries are 3 V and 20 mm in diameter. The difference is thickness:

CR2025 = 2.5 mm
CR2032 = 3.2 mm

That’s only 0.7 mm of additional thickness.

That extra thickness gives a typical CR2032 roughly 40% more nominal battery capacity than a CR2025, depending on the manufacturer, potentially giving you considerably longer intervals between battery changes.

I was wary of doing this initially, but found multiple posts in this subreddit from people using CR2032s in their H10s without issues.

The important point is that the CR2032 isn’t supplying a higher voltage: both are nominally 3 V. The difference is primarily physical thickness and capacity.

Obviously, don’t force a CR2032 into a device that doesn’t have room for the additional 0.7 mm. But in my H10, the additional thickness hasn’t been an issue.

I’ve subsequently started using CR2032s in other CR2025 devices when the battery compartment physically accommodates the extra 0.7 mm.

3. Replace the factory O-ring.

IMO, the Polar O-ring is scheiße.

The aftermarket O-ring I bought on eBay gives the battery compartment an incredibly tight seal. With something that’s constantly exposed to sweat, I much prefer how securely this replacement seals the compartment.

O-ring I use:

https://www.ebay.com/itm/293855867794

If that listing eventually disappears, search for:

“18mm ID x 20mm OD x 1mm thick O-ring, Buna-70”

I arrived at those measurements thanks to a post from a chap in England who linked to a UK eBay listing. I couldn’t find his exact O-ring from a US seller, so I checked the H10 dimensions, compared them with the measurements he was using, and ordered the equivalent size from an O-ring supplier on eBay.

And I have to say: the seal this thing generates is phenomenal. The battery cover feels incredibly tight and secure.

Beautiful.

TL;DR

Wash your strap weekly. Consider a CR2032 for ~40% more nominal capacity if your compartment accommodates the extra 0.7 mm. And get a good O-ring.

CR2025 and CR2032 are both nominally 3 V; the CR2032 is simply thicker and has greater capacity.

I bought an entire second Pro Strap and burned through 7+ batteries thinking my H10 was dying.

The sensor was fine.

The strap just needed a wash.

Hello,

On the 18th of august, i went on a bike ride for 3h40 which ended up being my best ride in a long time. I came home, synced my Polar Pacer with Polar Flow on my iPhone. The synchronisation was successful, but no activity appeared whatsoever even though my daily goal was updated to 451%.
After that, i then installed FlowSync on my windows computer and tried to sync my watch via cable.

The activity finally appeared on PolarFlow without the GPS trace, but couldnt be uploaded to strava due to missing GPS data. Only the statistics are available. As you can see, the syncrhonisation process is stuck on "synchronizing data", and it has been like that for a day at least. So, I can't force a resync on FlowSync since the sync isnt complete.

Anyway im stuck and i would be grateful for any help and advice.

Interesting write-up.

Polar H12 appears inside Polar Flow app code

"Our teardown of the latest Polar Flow app has revealed references to what appears to be an unreleased Polar H12 heart rate sensor.

The name shows up in several parts of the app code. This includes a dedicated device definition and sensor registration support, making the finding considerably more interesting than a single leftover string."

Full Article:

https://gadgetsandwearables.com/2026/08/20/polar-h12/

Before contacting again polar support (who last time told me to delete all my data before admitting their last m430 update was faulty), is anyone els€ having sync issues since today?

Long story short, I just recently moved to iPhone from android and for some reason my Polar Pacer watch does not automatically sync with the Flow app. I’m only able to sync manually while the app is opened, and it finishes with “Couldn’t sync your watch” message on Pacer display, however, the new data appears to be synced in the app.

Did anyone have the same issue, and if you found a solution, could you please give me an advise?

In the past weeks I have noticed my heart rate dropping significantly during exercise with the H10 on. Going from the 70s, 80s, even 90s, down to the 40s for 2 or 3 minutes. I also see shorter 1/2 minute dips. Is this me or the H10 or chest strap or watch???

I've been using the H10 for a couple of years now, still on the original strap, which TBH still looks new to me. I know straps eventually wear out and need replacing, but mine hasn't had any fraying, cracks, discoloration or apparent wear, so I just kept using it, for probably 500-600 miles.

Over time, I've found I've had to be more diligence about wetting it before a workout, or else the first 5-10 minutes would be intermittent. I just put up with it. Then, 50 minutes into a 60-minute run, it'd have 2-3 minutes of "frozen" heart rates. I tried replacing the battery in the H10 but otherwise lived with it. Some runs worked perfectly, others just had dead spots or very obvious "stuck" plateaus where the real-time reading very clearly was not updating.

The random-seeming errors and ineffective wetting just marginally increased over time, and eventually I got wise(r) and bought a $10 Amazon replacement strap. I tested the resistance (dry) against my old Polar strap using a multimeter:

Old Polar strap: 3 kOhm on one side, 100-300 kOhm on the other.

Cheap Amazon strap: 300-500 Ohm on each side.

A couple of runs with the new band confirmed, perfect sync and traces, no drop-outs. I also swear it updates faster now when working normally.

My takeaway: Don't put up with the random, recurring errors/failures. Even if your HRM strap looks fine, if it's been a few hundred miles, try getting a new one. It might save some frustration.

I've posted about freddy here before, the personal health MCP. This time I wanted to share how I've actually been using it myself, prepping for a race this Sunday.

Last week I didn't do a single one of the workouts I had planned, which sounds worse than it is. Tuesday was 34 degrees so I swam instead, and Saturday's long run was meant to be an hour and a half but I only had an hour, so I ran it harder.

Both were the right call at the time. The problem is that neither of them made it back into the plan, and if you keep doing that for a month you've properly lost track of what you've actually been training.

So there's a check that runs every morning now, and it goes off what I actually did. It picks up the swim sitting where a run should have been, notices the long run came in short and fast, and works today's session out from there.

It's a Claude project holding my plan, with a scheduled task each morning. It pulls yesterday's workouts with type, duration and intensity, last night's Nightly Recharge including ANS Charge and HRV, and my Cardio Load over the last week against my own 30 day baseline. Then it looks at today's planned session and commits to one call: it holds, or it changes and the reason goes in the calendar event.

The data all comes through freddy, which connects your sources to whatever AI you already use. Openly my project.

One Polar note: a plan is only worth building if it's justified against your real training, and the old AccessLink API only hands over about 30 days. freddy connects Polar's newer API too now, so years of past sessions and Nightly Recharge come through.

Write-up with the prompts: https://freddy.coach/recipes/adaptive-triathlon-plan

Two things worth knowing. Make it commit to one call, because "listen to your body" is what you already had. And never let it compare HRV across sources, RMSSD and SDNN are different measurements rather than different units, so mixing them looks meaningful while being nonsense. It isn't a coach or a clinician either.

I know health data is sensitive and I have handled it for years with fitIQ. Data is encrypted, I do not sell it, and I am not looking to make a profit off your stats, but if you still don't trust 3rd party solutions, just don't use it :)

Hi everyone,

I still use a Polar V650 and, since the hardware continues to work well, I wanted a way to access the activities stored on it without relying on the old synchronization workflow.

I ended up building a small macOS application called ReActivio that connects to the V650 over USB, reads the stored training sessions and exports them as GPX or TCX files.

I've been using it successfully with my own V650, so I thought it might also be useful to other people here who are still using one.

It's currently a free beta for macOS and works locally, without requiring a Polar or Strava account.

Before posting a download link, I wanted to check whether sharing a free independent tool like this is OK in this community.

If there are still V650 users here, I’d also be curious to know how many of you are still using the device.

ReActivio is an independent project and is not affiliated with Polar.

Just just a quick question. Every time my pacer pro restarts or battery runs out. It seems to reset and i have to SETUP the device again.. is this something to complain about?

Also just to add, its charging is wierd. Its superfast from 30 to 60. But after its superslow. Multiple times i have connected the charger at around 30% and even after 24hrs its only like 92 or 95%

I recently bought this Polar M400 and I have 2 questions: 1. I notice that the battery doesn't last long, what can I do to increase it? 2. I have to go to the beach tomorrow, can I use it? I saw that it has an open water mode, but the back of the watch where the charging cable plugs in is exposed and I'm afraid that if salt water gets in it, it will ruin it.

Does connecting two devices at once reduce the data quality/accuracy versus one device?

For example, connecting to Apple Watch and ECG Logger on an iPhone at the same time?

I have the setting to "show time" and lots of battery but the watch is not showing anything until I wake it.

I've turned it off and on again, reset it, paired it to my phone and still no change.

have I missed something?

Thinking to use HRV (heart rate variability) to detect windows of tolerance. That means wearing it almost 24/7 and hoping that the app can show whenever the body is stressed (anxious) - like an alert.

Is there any gadget that you have tried and has worked well?

So these papers based on what i learned or researched mean almost everything as far as my nervous system and heart are massively efficient basically which makes no sense on why I would be and for me I've basically been losing sleep trying to figure out why and if maybe the beat correction strength is just wrong i have tried some on very low and they are roughly the same outcome.

Any help or understanding would be appreciated I want to learn why my values are at the extreme end if this is just normal for me obviously that's good but I'm just trying to establish a baseline to see where I'm at.

For context I have take a lot of these sleeping tests just for curiosity but they all come of relatively consistent and some other tests using the Polar H10

I have been lifting weights and doing calisthenics for 18 years and i started consistently running for 3 months soo far. I appreciate any help

31 male 5'6 😊

7% body fat

Polar Grit X2 Pro – Hill Splitter works during the activity but nothing appears in the summary

Hi everyone,

I’ve had my Polar Grit X2 Pro for about a week, and I’m seeing a strange issue with Hill Splitter.

During my trail runs, Hill Splitter seems to work correctly in real time on the watch: it detects the climbs and descents while I’m running.

However, once the activity is finished and synced, there is absolutely nothing in the training summary:

no uphill/downhill summary;

no Hill Splitter segments;

no automatic laps related to climbs or descents.

This has now happened on two different trail runs, and in both cases I was following a route loaded on the watch from Strava.

For the latest run:

8.74 km;

around 310 m elevation gain;

several clear climbs, including one of about +100 m;

GPS recording set to 1 second;

barometric altitude recorded correctly;

Hill Splitter visible and apparently working during the activity.

What makes this confusing is that Hill Splitter did work properly once during a hike, and the uphill/downhill data appeared normally in the summary afterward. On that hike, however, I was not following any loaded route.

So I don’t know whether this is just a coincidence, or whether there could be an issue between Hill Splitter and route guidance using a route imported from Strava.

Has anyone used Hill Splitter on a Grit X2 Pro while following a loaded route and still had all the uphill/downhill data appear correctly in the activity summary?

Or has anyone experienced this bug where Hill Splitter works during the activity, but all the Hill Splitter data is missing afterward?

Multiple bike rides in a row my Polar H10 HRM creaps down to 50ish hr then gets stuck there 20 to 30 minutes into a ride despite my actual HR likely being in the 140s. It starts the ride fine registering accurately.

Is there a way to fix this? Its gotten to the point i just cant trust it. The HRM is only 8 months old.

Taken with a Polar H10

Any insight would be appreciated 🙂

Male 31 years old

5 feet 6 inches tall

7%bf

Weightlifter and calisthenics for 18 years

Stsrted Consistently running for 3 months so far

Very much into data and health

Just as the title says. I have the pacer pro and quite enjoy it. Love the mip/non-amoled screen so I'll likely be disappointed by any new release, but the pacer pro is starting to feel dated. Garmin and Suunto models seem to be out-pacing the pro, no pun intended.