Sennheiser MOMENTUM Sport Review, HR Earbuds Powered by Polar

Sennheiser Momentum Sport Review PolarSennheiser MOMENTUM Sport Review, Polar-Compatible Heart Rate Earbuds

Sennheiser is an excellent audio company and they’ve just made an interesting move to use their earbuds as a heart rate sensor during workouts. Jabra did a similar thing almost 10 years ago but what stands out here for Sennheiser is its tie-up with Polar, a leading Sports Tech company. For the first time, Polar allows a 3rd party direct access to its FLOW sports Ecosystem with these earbuds.

Let’s start with a summary review of the Sennheiser Momentum Sport earbuds with in-depth details further below.


More: $329.95/329.99 EUR

Verdict: ⭐⭐⭐⭐ - one less gadget to carry


MOMENTUM Sport earbuds are a great way to get heart rate and ditch your watch, heart rate strap or both. You’ll need your smartphone or a suitable smartwatch in range to record the workout and play the music. Even leaving your smartphone in your bag at the edge of a small gym room will work.

Sennheiser Momentum Sport Review Earbud apple

Sennheiser is set apart by the link to Polar FLOW, one of the leading sports apps, packed full of features ranging from scientifically validated insights to straightforward charts.

Sound quality and HR accuracy do NOT set the earbuds apart from the alternatives at this price level but, other than when running, the quality of both is good.

More: $329.95/329.99 EUR


  • Plays music, audiobooks or audio coaching – all supported
  • Produces heart rate and temperature
  • Supports two simultaneous Bluetooth links
  • Nice, compact carry case for charging
  • Tether for carrying
  • Good sound from a fairly large driver (speaker) with higher quality aptX Adaptive CODEC support.
  • I Charging supported
  • Temperature should work on Wahoo devices.


  • Playback sound quality impacted by environmental noise
  • No ANT+ support, no caching, no HRV
  • Slightly uncomfortable for me (our ears are all different)
  • Tricky to get the retention wings to stay in the right place, so ensure you first REMOVE the neutral wings included out of the box.
  • Inaccurate HR when running (may vary person-to-person)
  • Some wind noise even with wind noise reduction when running (but OK)
  • You need a smartphone and/or smartwatch with you for exercise

Sennheiser Momentum Sport Review Earbud apple

Why? What’s The Point? What Problems Are Solved By Momentum Sport?

TL;DR – Many runners and gym/classgoers like to work out to music. MOMENTUM sport simultaneously gives you quality audio and potentially accurate HR.

Problem 1 – Accuracy: The ear is a GREAT place to measure heart rate accurately.

Heart rate during workouts is the single most important metric for sports and wellness tech companies. It is a starting point for the algorithms that analyse your efforts and assess your stress and recovery. Yet most people use heart rate from pulse signals on the wrist. This is the worst place to take a heart rate measurement and is often wrong for several reasons linked to how you exercise, your physiology and the environment you exercise in.

Problem 2 – comfort & convenience: There are ways to get accurate HR including using a chest strap but lots of people don’t want to do that or can’t do that.

Problem 3 – Lots of Gadgets to carry and charge: Many people listen to audio but that either requires them to carry a smartphone or get the audio from their watch, and that latter option significantly shortens battery life.

Momentum Sport is a potential solution to all those problems



Possible Ways to Use Sennheiser MOMENTUM Sport

The most obvious use is as regular earbuds for playing audiobooks or music from your smartphone or watch.

When recording the heart rate transmitted by the buds, you can use any recording device – a watch, smartphone app, gym equipment, or bike computer. The uniqueness of the MOMENTUM buds lies in their direct access to the Polar FLOW smartphone app and ecosystem. This is important because, typically, sports ecosystems like those by Suunto, Polar, and Garmin were ringfenced to require the purchase of a similarly branded watch.

Finally, there is a more advanced use case. The earbuds also serve as a source of body temperature. If you pair them with a high-end Polar watch, some new temperature screens will appear on the watch. This information will also be available in FLOW. Perhaps you could use that to regulate your efforts on hot days and hydrate more efficiently. Excess heat has a significant negative impact on athletic performance.

If you use an indoor training platform like Zwift or Peloton, the earbuds can pair with such a platform and simultaneously with another device like a watch.

Try these combos

  • Music from your smartphone – heart rate transmitted to your watch
  • Music from your smartphone – heart rate transmitted to your smartphone
  • Music from your PC – heart rate transmitted to Zwift or Peloton
  • Audio coaching from your Polar Watch  – heart rate transmitted to your watch
  • Music from your iPad – heart rate transmitted via Wahoo KICKR to SYSTEM or Zwift

Sennheiser MOMENTUM Sport – Detailed Technical Specifications

These are decent specs and capabilities but by no means the best on the market. You probably have to accept slightly lower audio quality to stand up to the rigours of sweat, dirt and humidity during exercise.

  • Heart Rate and Temperature Supported
  • Battery lifespan: Up to 5.5 hrs music playtime with earbuds; Up to 24 hrs overall music playtime with charging case (test condition: iPhone, mid-volume level 85 dB)
  • Charging time: Approx. 1.5 hrs for fully charged; After 10 min charging 45mins music playtime. Remark: Ambient temperatures >30°C and Qi wireless charging leads to extended charging times
  • Supported codecs: SBC, AAC, aptX, aptX adaptive (Next generation on from aptX HD)
  • Weather resistance: Earbuds: IPx5; Charging case: IPx4
  • Speaker type/size: TrueResponse dynamic, 10mm diameter (10mm is good but others are 12mm)
  • Speaker frequency range: 15 Hz to 18 kHz (Human hearing range is 12Hz to 20KHz)
  • Wearing style: True wireless stereo earphones
  • Ear coupling: Ear canal
  • Connectivity: Bluetooth 5.2 compliant, class 1, 16mW (max), RF Range 40m – line of sight.
  • Simultaneous pairings: earbuds can be paired to 2x Audio sources over Bluetooth and 2x Sports devices /apps over BLE (Bluetooth Low Energy)
  • Ear Temperature: Bluetooth Health Thermometer Profile Supported
  • Transmission frequency/modulation: 2,402 MHz to 2,480 MHz; GFSK, π/4 DQPSK / 8DPSK
  • Supported profiles: A2DP, AVRCP, HFP
  • Speaker principle: Dynamic
  • Speaker sensitivity: 110 dB SPL (1 kHz / 0 dBFS)
  • Speaker THD: <0.25% (1 kHz / 94 dB)
  • Active Noise Cancellation: Hybrid Adaptive ANC
  • Mic principle: MEMS
  • Mic frequency range: 100 Hz to 10 kHz
  • Mic pick-up pattern: 3 mics per earbud, beamforming for noise reduction
  • Battery type: Built-in Lithium-Ion rechargeable batteries; Left/right earbud: 72 (MC1254) / 75 mAh(CL1254); Charging case: 850-950 mAh
  • Power supply: 5 V⎓, 1000 mA max; USB charging via USB-C socket at charging case; Qi Wireless charging
  • Magnetic strength field: Earbuds: 1.86 mT; Charging case: 250 mT

Sennheiser Momentum Sport Review Earbud spotify


Sennheiser MOMENTUM Sport – History & Future of Sport Earbuds

Momentum Sport is Sennheiser’s first audio earbud to include heart rate detection. The company has a long history of high-quality audio products; indeed, my main home headphones are Sennheiser, a brand I trust.

Jabra Sport Pulse and Jabra Elite Sport are the only earbuds that spring to mind that combine the features of audio and heart rate detection. Both were released well over 5 years ago, so this is not a new area of sports technology by any means.

I don’t know why there hasn’t been more competition in this space in the intervening period. Perhaps avoiding audio dropouts, ensuring widespread compatibility, keeping buds in the ear, and handling external noise have presented more than enough challenges without companies having to worry about losing heart rate signal as earbuds move and the buds themselves getting confused between heartbeats and footstrikes on the road.

Hearables are continually touted as one of the areas of growth in the overall wearables market, but that growth potential has been confused with the historic growth patterns, which are simply based on audio and not on biosensing. The market for biosensing in the ear has been tiny as products kept similar formats and capabilities over many years.

What’s next?

There will undoubtedly be ever more clever ways to improve battery life, improve sound quality, increase sharability, and add peripheral features typified by Apple’s FindMy. The next big leap will only come from the next generation of biosensing tech to detect new bodily metrics. But how many of us will want that in our ears when offered the alternative of a watch, a band, or a ring? My answer would be, “Not many.” Audio is the primary driver and will remain so for the foreseeable future.


Sennheiser Momentum Sport Jabra Comparison
Size comparison of Sennheiser to Jabra Elite – highly similar

Sennheiser MOMENTUM Sport – Techy Insights

Eardrum temperature is measured using two Negative Temperature Coefficient (NTC) thermistors and proprietary algorithms. The earbuds support a standard Bluetooth body temperature ‘profile’ called BLE Health Temperature Service (HTS). Thus these earbuds will transmit temperature to any app or device that supports that standard including the Polar Grit X2 Pro watch and the Polar FLOW app.

Heart rates are determined by Photoplethysmography (PPG) in the same manner as most modern wearables. Momentum Sport does this in real-time and does not cache or store heart rate. The technology in the ear should be able to accurately measure HR during sports but not HRV and the company doesn’t claim that in any case. Indeed no optical HR company produces HRV during workouts although most should be able to get accurate HRV at resting levels, it’s more that this feature is better suited to other product formats such as watches.


Sennheiser Momentum Sport Bluetooth

Sennheiser MOMENTUM Sport – Accuracy Tests & Results

During my testing, I found that Momentum Sport suffers from cadence lock during running workouts but was sufficiently accurate for other exercise types. Here are some examples compared to a variety of other sources of heart rate during the same workouts.


Cadence lock occurs when your footstrike is mistaken for a heartbeat; this can usually be eliminated by a more developed heart rate algorithm. However, I wasn’t surprised to find a cadence lock on this newly launched product using new tech for running for the first time. Cadence lock won’t necessarily happen for all runners.

I have a scientific-grade temperature sensor from CORE. It measures core body temperature, which is different from ear temperature. I confirmed that difference visually and didn’t notice anything especially wrong with Sennheiser’s temperature measurements, the two trended similarly but were not the same (and you wouldn’t expect them to be +/-1.5 Celcius). I did not figure out a way to overlay the two temperature tracks on one chart, mostly because the Polar FLOW ecosystem does not allow for the export of body temperature data. I perhaps could have paired Momentum Sport with a Wahoo or Garmin bike computer to record the temperature but didn’t! I wasn’t entirely sure of the point as Sennheiser’s temperature metric appears sufficient for avoiding the extremes during casual sports usage.

Sennheiser has validated HR accuracy tests with the University of Munich (I asked for a copy and will update here if received).

Finally whilst the ear is a great place to record temperature it is susceptible to temperature flux whereby extreme environmental temperatures like -10 Celcius will affect readings (wear a hat).

Using Sennheiser MOMENTUM Sport

The wings and tips are interchangeable and easy enough to fit. A neutral wing comes pre-installed out-of-the-box. However, there is no guide to get them in a precisely correct position, and if not done properly, an incorrect wing position stops the buds from charging when placed in the charging case. The wings also relatively easily become detached, so I’m not sure how long I will be able to avoid losing them. Once lost, the buds will much more easily come out of the ear during exercise.

The buds look great, but I thought the charging case could have been better-looking and with a more refined design than simply having a flap covering its USB-C charge port. My partner disagreed and loved the looks.

My partner has small ears and was surprised that the Momentum Sport fitted as earbuds usually don’t. I didn’t find a problem putting them on and getting a secure clip-in with the wings. I did, however, find them a little uncomfortable after running with them for an hour.

The sound quality was pretty decent, but I’ve experienced better in earbuds. Though, to be fair, there’s little point in having highly specified audio equipment when doing exercise, especially when you consider wind noise. On that note, there is a noise-cancelling option to eliminate wind noise, but it doesn’t completely stop wind noise. However, external noises were muted in this mode and the normal ANC mode noticeably dulled ambient sounds.

Momentum Sport has no buttons, so taps, multiple taps, or a press-and-hold gesture control all its features. These gestures, both during calls and during sports, are configurable but work well on the defaults. The only criticism I have here is that the gestures are activated multiple times when inserting and securing the buds in the ear – it’s not a major problem, just a bit annoying.

A clever feature that I especially liked was the ‘sound zone’ mode. This allows you to make a preset of the equalizer and noise control setting and have that preset activated based on your location. For example, once you are running 50m from home, you might automatically enable a mode with booming bass and wind control. The only downside I could think of here was that it requires the phone to be present so won’t work when you are working out and listening to music via your sports watch with the phone left at home.


Using Sennheiser MOMENTUM Sport with Polar FLOW

You can get workout data into Polar FLOW either by taking your phone with you as you exercise or directly recording the workout using the Polar FLOW app. Alternatively, pair your Sennheiser earbuds with a Polar watch. I used the Grit X2 Pro, but any sports watch that supports Bluetooth earbuds should work.

The former case is the more unusual one and one of the key reasons for buying Sennheiser’s Momentum Sport. You get the core data that comes from HR but also some of Polar’s advanced metrics. Here is the full list: Heart Rate (Min/Max/Average), HR Training zones, Body Temperature (Min/Max/Average), Graph of the body temperature, Training Benefit, Training Load Pro, Duration, Calories, plus Distance and route if, for example, using the Running sport profile in Flow.


Sennheiser MOMENTUM Sport Review – Take Out

Momentum Sport is indeed an interesting product, albeit an expensive one.

You are paying a premium either for the link to Polar’s excellent FLOW sports ecosystem or that it helps you use your favoured smartphone app without the need to buy a sports watch or other sports HR sensor. You probably do save some money there and add convenience. However, I have some concerns about the design and implementation of the product.

I have reservations about the wings and their ability to stay in place, and I harbour doubts about accuracy during running due to cadence lock. Sennheiser should be able to address the latter problem with firmware updates. Other than that, the audio specifications of the earbuds are good, certainly not the best, but more than capable of fulfilling the tasks for which you’ll purchase them.

The addition of temperature monitoring during sports is good but I am not convinced that many of the kinds of athletes who want temperature monitoring will want it in an audio product.


More: $329.95/329.99 EUR

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10 thoughts on “Sennheiser MOMENTUM Sport Review, HR Earbuds Powered by Polar

  1. Thanks for the review! I’d be really interested to know if the body temp can be shown on a Garmin, and if/when they fix the cadence lock for running.

      1. your results seem a bit better than mine. At least with mine the error is obvious. With the example you show someone else (without a comparison HRM) would be none the wiser.

  2. Body temp is intriguing but not enough to warrant the expense over my current combo of optical armband HRM (Coospo or Scosche) and an Aeropex bone conduction headphone (which has other advantages over this).

    Thanks for the review, but the price would need to come way down (like 50%) to enter my consideration range.

  3. Hi 5krunner.

    I’m interested in these because of the body temp measurements and will potentially get these and the vantage v3 to pair. I currently use the v2 and held off on buying for now as the feature upgrade wasn’t really worth it to me.

    I don’t care about the poor accuracy on hr and the v3 as well, I’ve long learned that for my needs, it’s not accurate enough. So I’ve paired the v2 with oh1+/verity sense band for a long time and will do so even with the v3.

    Would you be able to test if this combo works? V3 getting hr data from verity sense band or chest strap, and also getting the temperature data from the earbuds?

    Would highly appreciate it if you can confirm or test it.

    If that combo works, I’ll order the earbuds and polar vantage V3 haha.

    Thank you

    1. I dont think it will work. there is a single pairing from the earbuds and that pairing will include hr

      i’ll ask polar as i’m unsure how i could be certain of the source of hr that is shown

      1. Thank you and especially reaching out to polar. I may try emailing them myself but I think you’ll have better luck.

        I’ll have to think of some ways to get just the temperature data and not have it interfere with hr data from a verity sense band. I can’t trust wrist based optical hr sensors, they’re just not good enough for my use which is why I use the verity band.

        With summer coming and I’ll be switching over to outdoor training, I was/am curious about tracking temperature data from my workouts.

    2. seems you can do what you want tho Core shoudl be cheaper
      I asked “Can I pair Momentum and a Polar H10/OH1 at the same time and get temp from MOMENTUM and HR from OH1/H10?”
      Polar said “Our external setup prioritisation is done so that the top priority for HR is given to a sensor that can record R-R intervals (e.g., H10). Then goes a product that records both HR and body temp (e.g., MOMENTUM Sport). The least prioritisation is given to other sensors that only record HR (e.g., Verity Sense or OH1). In practice, if you want to use MOMENTUM Sport for body temp and another sensor for HR, you need to connect a sensor with R-R interval recording functionality, such as H10 or H9.”

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