% of HR on Garman 705

...and it will display heart rate *only* in BPM.

I think all Edges have the same basic menu system, but maybe because you paid extra the 705 can do HR as a percentage.

For the Edge 305: although the display is fixed, you can set it to alert you for different HR zones - either when your HR is above or below that zone's threshold - and these can be based on a percentage of your max HR, so without too much trouble you could make it beep when your HR exceeds 90% of max (for example, which is zone 5) or alternatively when it goes below 90% of max.

I have done this for training purposes and found it really annoying having the thing beeping like a maniac because it thinks I'm not trying hard enough

It shows the zone so if you have these set up you can keep it in a zone but the 305 doesn't show the % of max

on my 705 the path to that setting is:

>Settings>Units>Heart Rate> and then you can select either 'Beats per minute' or '% Max HR'

I wonder if Garmin do the percentage calculation correctly. Most of the time they do the very basic calculation and just times the max by the percentage but this isn't correct.

Eg. To work out 80% of your max if you have a resting rate of 60bpm and a max of 200bpm is;

Most common but incorrect is 0.80 * 200 = 160bpm.

The correct calculation is (200-60) * 0.80 + 60 = 172bpm