Onrhythm 500 HRM Watch and Bluetooth Chest Strap - Red



MRP : ₹ 3,999

Made In : China

Made for athletes who want to measure their heart rate and make progress
Make easy progress with the interval training mode and the exercise intensity indicator.
Sizes guide

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Parameter measurementStopwatch, heart rate (BPM and %MHR), calories).
CoachingTarget zone (BPM or %MHR) - intensity tracker - split - time per lap
Ease of useCoded Bluetooth transmission: optimal connection with the watch
WaterproofWatch: 5 ATM (swimming) - belt: 1 ATM (water projection)
User comfortFabric belt for more comfort.
Warranty2 Years
Technical Information

Track data
Stopwatch, heart rate monitor (BPM et %MHR), calories burnt: immediate and total.
Target zones
Setting your target zones helps you to organise your training sessions. It shows you, in real-time, whether you are in the zone you have set. With the ONrhythm 500, you can set heart rate target zones (in BPM or %MHR) and energy expenditure target zones (kCal/hr).
Training intensity tracker
The ONrhythm 500 automatically indicates the degree of intensity measured by your heart rate in real time: very light, light, moderate, hard and very hard.
You can configure a complete interval workout. For example: time for warm-up, action, rest, recovery, number of series and rest time between series.
Stopwatch with split-times (lap)
You can use the split-time feature to measure multiple intervals during a workout,and then measure your improvement for specific intervals.
Time, date, alarm, backlighting.
Heart rate monitor
You can use the Bluetooth Smart belt when working out in a group as it does not interfere with other heart rate monitor frequencies.The technology is also less sensitive to electromagnetic interference, allowing for excellent connection with the watch.
Fabric belt.
The fabric material of the belt is also much more comfortable for long workouts and is machine-washable (without the sensor).
View detail of the last 5 workouts
Watch: CR2032 included - Belt: CR2032 included
Watch: 5 atm (swimming) - Belt: 1 ATM (water projection)
Belt compatibility with smartphones
The Bluetooth belt is compatible with all available sports applications. Note: it is not possible to send heart rate data from the belt to a smartphone and watch simultaneously. You can only use one or the other.
Information / Concept / Technology
Wrist : 90.0% Polyurethane (PU), Wrist : 10.0% Stainless steel Structure : 70.0% Polycarbonate-Acrylonitrile Butadiene Styre(PC-ABS, Structure : 30.0% Stainless steel Inside room : 100.0% Printed Circuit Board Lens : 100.0% Polymethyl Methacrylate (PMMA)


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I had a older version of the same product
Used for 7 to 12 months
Poor performance, keeps on disconnecting, chest band is not comfortable to wear, elastic has lost its properties
Feed back
Used for 2 to 8 weeks
It is a good heart rate monitor for the cost. It has all basic functions useful for average sportsman.
Initially you may have to go to local Decathlon dealer to get it activated.
ease of setting up hrm
Used for 2 to 8 weeks
it is a real challenge setting up this HRM! you really have to be tech savvy and that i am not I go forward bravely Jude
Bluetooth connectivity
Used for 7 to 12 months
The bluetooth spec mentioned it is compatible with all common activity apps.
When trying to pair it doesn't work and request a pairing code.

After some research on the geonaute website it appears it can only be paired to a endomono and runtastic pro.

I would not recommend this heart rate monitor
Used for 2 to 8 weeks
Device broken with the first day of use
Just wear in hand and its band broke
Response of the brand
Hello Mahesh,

Thanks for taking the time to write to us,

We are really sorry for this to happen, you can visit to your nearest Decathlon store, they will help you to find the best possible solution.

 Hope I was able to solve your concern. For further assistance, please feel free to write back to us.

Used for 2 to 8 weeks
great piece of kit, works all the time, no issues
Difficult to connect!
Used for 2 to 8 weeks
It always took me sooooo long to connect! Once it is connected, it will hang after around ten mints and connect again! So difficult to use!
Response of the brand

I'm sorry to hear that you have had issues connecting to your Onrhythm500 HRM.

There are two points you can check:

Do you moisten the sensors on your belt?
Is the batter well charged?


If you are able to return to store we can offer check with a replacement battery for you or offer an exchange or refund. 

Kind regards, 

David Daker
Market Manager Nutrition,
Electronics and Accessories,
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