@ Version 1.0 ... Re: heart rate measurement
Being off by 25 bpm can be a major problem.
When exercising the max heart rate is a formula... 220 minus your age.
So when you're 20... that's 200 bpm.
When you're 50, that's 170 bpm.
If you're trying to get back in to shape, you could be at 170 bpm while your monitor is showing 145.
That's an accident waiting to happen, especially if your doctor tells you to do some exercise but not to exceed X like 145 bpm and you're really doing 170 bpm.
Also there are two types of monitors.
Photoplethysmography which is measuring your HR via an LED scan, and an EKG which is taking an electronic signal over a sensor or between two sensors. Two different methods.
You can get 'medical grade' devices as a consumer if you know where to shop. They do make and sell portable (2 x AAA battery) finger 'Pulse Ox' monitors. (Photoplethysmography) However these are not conducive to use while trying to work out.
But I digress. The point is that having a monitor off by 25bpm can be dangerous and its an accident waiting to happen. This is something to be a major concern because there are watches and monitors (besides Garmin) that have been making heart rate monitors for years that are more accurate.