Heart Rate Monitor

[andydormer]

Hi, sounds a good experiment.

My advice is not to trust the waterproofing of a polar brand HRM watch. I'm on my third Polar brand watch, none were reliable in the water. The first flooded in the swimming pool (polar website said it was suited to swimming but I once removed the back to replace the battery and may have damaged the waterproof seal) the second was rated to a greater depth and this died snorkelling to 3m (never been opened). My current one is suited to an even grater depth and steams up after going near water.

I'd therefore keep the watch dry - like the inside of a torch idea - but you'll need a model that keeps a record of your HR to download to a pc later, or you'll just get a max HR and possibly average.

The chest strap of the monitor may be impeded by the BCD straps, but you can check this easily by kitting up at home and seeing if the watch still shows a continuous recording.

Keep us posted.

[sailorbuoy]

OK - so what if the HRM was inside the drysuit? Clearly it won't get wet (well not very wet anyway!! But what about pressure - will keeping the suit equalised prevent a pressure build up or am I displaying a complete failure in my knowledge of physics?

Any ideas folks?

[Thunderbirdchris]

Would laying on hands and counting be something to consider?

If wrist/neck/groin pulses inaccessible try temporal (just behind the temples).

If you're wanting to compare rates at different pressures could you mark waypoints on your computer and correlate the two later?

Just a thought,

Chris.

Effect of immersion, submersion, and scuba diving on heart rate variability -- Schipke and Pelzer 35 (3): 174 -- British Journal of Sports Medicine
Commentary -- Wilmshurst 35 (3): 180 -- British Journal of Sports Medicine

[String]

Originally Posted by sailorbuoy

OK - so what if the HRM was inside the drysuit? Clearly it won't get wet (well not very wet anyway!! But what about pressure - will keeping the suit equalised prevent a pressure build up or am I displaying a complete failure in my knowledge of physics?

Any ideas folks?

Thats what i do and what i warned about. A drysuit is at ambient pressure. Although there's no water in there its still at 3 atmospheres at 20m and so on.
Thats how i lost a mobile phone (display cracked).

[Crieagle]

Originally Posted by Thunderbirdchris

Would laying on hands and counting be something to consider?

If wrist/neck/groin pulses inaccessible try temporal (just behind the temples).

If you're wanting to compare rates at different pressures could you mark waypoints on your computer and correlate the two later?

Just a thought,

Chris.

Effect of immersion, submersion, and scuba diving on heart rate variability -- Schipke and Pelzer 35 (3): 174 -- British Journal of Sports Medicine
Commentary -- Wilmshurst 35 (3): 180 -- British Journal of Sports Medicine

Go one better and dive with a nurse, female of course and let her do the hands bit, dependant on where the hands are laid and how hot said nurse is will probably affect heart rate JAT






Ok crap idea.............

coat

[machiavelli]

Originally Posted by Thunderbirdchris

Would laying on hands and counting be something to consider?

I'm not sure you could take a pulse wearing 5mm neoprene gloves.

Polar do a OEM receiver module for their heart rate transmitters. It's intended to be built into gym equipment. You could construct something with this and a data logger/embedded computer in a submersible housing.

[String]

Not convinced the very low power signal from the chest strap would penetrate water enough for some of these land designed things to work..

Although it would appear the new uwatec thing uses a bog standard polar chest strap.

Whether their model (or ANY deco model) knows what to do with pulse rate or even if it has any noticeable effect is a different story


Best bet i think is wear the chest strap, put the watch in undersuit pocket and dont go too deep.