Sennheiser's Momentum Sport headphones track your heart rate and temperature – but they're frighteningly expensive

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Sennheiser’s Momentum Sport headphones combine audiophile-quality sound with fitness-tracking features usually reserved for smartwatches. However, the price is intimidatingly high and the functionality won’t be useful to everyone.

The Momentum Sport buds deliver detailed sound and powerful bass, thanks to Sennheiser’s new 10mm transducer. They outperform all of the bone-conduction cycling headphones I’ve tested and most in-ear options.

While they don’t keep your ears fully open, the buds employ built-in microphones to pick up traffic noise, keeping you alert on the road.

The range of features is extensive, the fit remained secure throughout testing, and the buds and charging case have a premium feel. 

However, to get the best out of the integrated biometric sensors, you’ll need a Polar smartwatch – and if you already own such a device, you may not see the need for headphones that do the same job. 

Furthermore, these are some of the most expensive cycling headphones I’ve tested, at £279.99 / $329.95 / €329.90 although, at the time of writing, they’re available in the UK for £218.49.

Sennheiser Momentum Sport specifications

The Momentum Sport headphones’ USP is the biometric sensors in the left bud, which record heart-rate and temperature data.

Sennheiser has partnered with Polar and you’ll need to download the Polar Flow fitness tracking app to record the data captured by the sensors. 

You can also view your fitness data ‘live’ on your smartphone, without the Polar app, using Sennheiser’s own Smart Control app. This is of limited appeal unless you want to have one eye on your phone while running or riding.

Compared to bone-conduction headphones, in-ear devices are less adept at keeping you aware of traffic noise. However, Sennheiser has employed a ‘semi-open’ design and devised a Transparency mode, which uses the external microphones to dial some ambient noise into the mix. 

You can switch to Adaptive Active Noise Cancelling mode when you want to block out distractions and there’s an Anti-Wind setting. This range of listening options makes the Momentum Sport headphones more adaptable and better suited to cycling than many rivals.

The headphones have an IP55 water-resistance rating, sufficient to withstand a jet projected from a nozzle. They come with three pairs of ear tips and four fins to tailor fit, giving you 12 possible combinations. 

The buds snap magnetically into the luxurious-feeling, round-cornered case for charging via USB-C, with wireless charging also available.

Battery life is only six hours of playback (24 hours with the case), although that’s long enough to listen to the majority of the I, Partridge audiobook – back of the net! Charge time is 90 minutes, with 10 minutes giving you an hour’s listening. 

The buds are comparatively heavy at 6.4g each, including fins and tips, and they’re larger than many in-ear headphones, which could be an issue for those with petite ears.

The Smart Control app houses a wealth of features, including an equaliser, a 'find my headphones' function and Sound Zones, which enables you to trigger bespoke settings automatically as you arrive at a given location, such as the office or gym.

You can tap the buds to control playback or you can make contact with your face next to your auricle and the sensors will detect the tap – modern-day witchcraft.

Sennheiser Momentum Sport performance 

Much of my 20 years’ journalism experience has been while working on guitar, vinyl and tech magazines. In that time, I’ve reviewed a wide musical spectrum of amplifiers, effects pedals, turntables and headphones.

I’ve recently been testing a range of bone- and air-conduction headphones designed for cycling and running to find out which are best suited to the rigours of an active lifestyle.

To assess the performance of the Momentum Sport headphones, I used them on my daily commute during late summer and early autumn, for around 80 miles of running and several gym sessions.

This enabled me to get a thorough picture of the fit, comfort and hi-fi performance, while trying out their fitness-tracking functions.

Fit 

The range of fit options is reassuring, but I’d advise ensuring you’re fully confident both buds are secure before heading out. Setting off on my first commute with £279 headphones in my ears elicited a level of anxiety I’d only previously experienced after drinking four double espressos and checking my bank balance.

Using the large tips and fins, the buds slipped out of my fussy ear canals on my first run. After using Sennheiser’s Fit Analyser, which scans your lugs, I settled on medium tips and fins, which was deemed a ‘good’ fit.

The headphones have stayed securely in place throughout testing, surviving short gravel sections, cobbled streets – and ample wind, rain and sweat. 

However, I’ve had some charging issues with the fins installed, preventing a solid connection with the port – which I didn't spot until I came to use the headphones and found one of them out of juice.

Sound quality

As you’d hope given Sennheiser’s headphones heritage, the audio experience is detailed, muscular and balanced – you won’t struggle for volume, even when descending at speed. 

The only cycling headphones I’ve tested that perform better are Sony’s LinkBuds, which have a slightly more widescreen presentation and captivating top end than the bass-forward Momentum Sports. The new Google Pixel Buds Pro 2 are of a similarly high quality.

Electronic music is reproduced particularly well, with beats, pulses and lower-mids punchy and focused in the same vein as a good set of bookshelf speakers.

The echoey percussion and Elizabeth Fraser’s ghostly vocal on Massive Attack’s Teardrop made me want to hit repeat and do another lap of the block before arriving at work.

On the way home, the sonorous, thudding toms and doleful baritone vocal on The National’s Lemonworld were every bit as immersively melancholic as you’d wish, with every element of the song clear and present.

It’s useful being able to adjust the ratio of music to traffic noise in Transparency mode, acting as your own soundman. The wind can become cacophonous, which is where Anti-Wind mode helps. However, I preferred to use Transparency mode and adjust to taste in order to stay fully alert.

As ever, I’d recommend bone-conduction headphones if your priority is completely uninhibited road awareness – and certainly wouldn’t advise selecting Anti-Wind mode and giving My Bloody Valentine’s Loveless full beans.

Fitness tracking 

After downloading the Polar Flow app, I tested the heart-rate tracking using 20-minute gym sessions on the treadmill and indoor bike – both available from a long list of sport profiles in the app.

I varied the intensity throughout the sessions and compared the heart rate reading to that from my Garmin Vivoactive 4S smartwatch. 

The two were very close throughout, with the Momentum Sport recording an average heart rate of 120bpm and maximum of 165bpm from the bike session – with an average body temperature of 36.7ºC. 

The Garmin logged an average of 121bpm and a maximum of 160bpm. 

I can’t say which device was closest to the truth and heart rate straps are always the most accurate way to measure heart rate. 

The result from this one-off activity seems impressive, but because I don’t own a Polar watch, I had to rely on my smartphone to view the data or access controls mid-ride. 

While for outdoor cycling I could mount the phone on my handlebar, I wouldn’t want to carry my phone with me and use it during a run – particularly during interval training when you need to hit the lap button frequently and keep an eye on your pace.

The range of functionality and data available mid-ride or run is greater on a smartwatch, so to get the best out of the fitness tracking in the Sennheiser Momentum Sport, you really need to buy a Polar watch. The cheapest one available on the Polar website at time of writing was £139.50, which would be a bitter pill to swallow having already splashed out on the headphones. 

Sennheiser Momentum Sport bottom line

Sennheiser has utilised all its experience to produce some of the best-sounding cycling headphones on the market. 

The fit options and use of tech to ensure you can hear the world around you are also impressive. 

However, it’s the Momentum Sports’ USP – fitness tracking – where I see issues. In a nutshell, you need a Polar smartwatch to use it to its fullest, yet anyone with a smartwatch already has that functionality.  

That tech contributes to a prohibitive price that I wouldn’t be prepared to pay with my own money. 

You could buy either the Shokz OpenFits – currently available for £119 – or Sony LinkBuds (£149) and a decent entry-level cycling smartwatch for around the same money as the Sennheisers.

There’s a lot to like here and I would gladly use these as my regular running and cycling headphones, but for me the value proposition doesn’t add up.

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