Freediving not beeing a popular activity enough, you won't find any heartrate monitor especially designed for this purpose. At best, some HRM specifications indicate "waterproof" or "ok for swimming".
Because a lot of people (as myself) was wondering if a heartrate monitor could be used underwater and because the device behavior in water was more suspected then really known - in spite of some very interesting opinions about the question on this forum - I finally decided to buy the relative cheap Polar A5 (wich is actually the same as the A3 with one more useless calory burning option) for 65 euros.
I can now say : yes, it works very well, with no lost of measure precision, at least until 10 feet and in a pool. I don't know how radio waves react in the salted water of seas or by higher pressures, maybe variation of water composition and density may affect them. The watch is 30m waterproof and the chest belt holds its position well by wearing a diving suit, otherwise it slips down when moving fast.
The heart rate is not a crucial information, it just helps knowing youself better. For exemple it is impressive to see how fast the beat slows down when starting a static apnea, then rises up again in dynamics, and so on...
ps : to save battery life try getting your chest belt electrods dry after using them, when they are wet (by perspiration or else) it activates the transmitter.
Because a lot of people (as myself) was wondering if a heartrate monitor could be used underwater and because the device behavior in water was more suspected then really known - in spite of some very interesting opinions about the question on this forum - I finally decided to buy the relative cheap Polar A5 (wich is actually the same as the A3 with one more useless calory burning option) for 65 euros.
I can now say : yes, it works very well, with no lost of measure precision, at least until 10 feet and in a pool. I don't know how radio waves react in the salted water of seas or by higher pressures, maybe variation of water composition and density may affect them. The watch is 30m waterproof and the chest belt holds its position well by wearing a diving suit, otherwise it slips down when moving fast.
The heart rate is not a crucial information, it just helps knowing youself better. For exemple it is impressive to see how fast the beat slows down when starting a static apnea, then rises up again in dynamics, and so on...
ps : to save battery life try getting your chest belt electrods dry after using them, when they are wet (by perspiration or else) it activates the transmitter.
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