[clug] [OT] Re: Heart rate monitors and GNU/Linux

[Alex Satrapa]

On 22/09/2009, at 09:42 , BAXTER,Adam wrote:

> This is getting OT but you'd think that the wearable (watch-like)  
> monitors could get your heart rate from your wrist, avoiding having  
> to wear one of those damned chest straps.

Getting heart rate from the wrist would be akin to tracking guineapigs  
using a seismometer mounted over the San Andreas fault line. Over the  
chest is the best place to be reading the electrical impulses from the  
nerves controlling the heart muscles. By the time you move the sensor  
to the wrist, you'll be diminishing the signal from the heart and  
masking it with the electrical signals from the muscles in the  
shoulder and arm.

Trying to detect the vibrations caused by blood flowing through the  
arteries is fine when you've found someone lying on the ground  
unconscious, but once someone starts exercising that tiny vibration  
will be masked by the exercise they're doing. So rule out vibration/ 
sound based heart rate monitoring for exercise.

There are also finger-clip type readers called "Pulse Oximeters[2]",  
but you have to clip the detector onto part of the body that is (a)  
thin and (b) has high circulation (ie: a finger). The reader will not  
work if you vibrate it - the instructions clearly state that you must  
stay still! Imagine trying to keep your finger still while riding a  
bicycle!

Alex

[1] http://www.ehow.com/how-does_4597151_heart-rate-monitor-work.html
[2] http://www.howtodothings.com/health-and-fitness/a4404-how-to-read-a-pulse-oximeter.html