Polar Heart Rate+Garmin GPS

Unlikely, as the wireless transmission technology is different (WIND for Polar and ANT+ for Garmin) and the proprietary analysis software is different for the two brands. I used Polar (CS500) until recently but switched to Garmin because of the much greater compatibility between the head unit and sensors with ANT+. It also depends on what you mean by 'align' - if what you want is all of the data on one chart then, as far as I'm aware, no.

Actually, I expect you can do this reasonably easily with excel. I don't have a Garmin at the moment (thinking of getting one for my next big adventure, but unsure if it is up to the job...) but from their website you can "export a .TCX file for other fitness programs and .KML for Google Earth. From the Splits page you can export a CSV file with the details of your activity."

One of these has to be fairly close to a GPX file, and in most cases they will have a time stamp on them. Import it into excel (it will probably be an .xml file in disguise) and also import the HRM file that Polar's training software exports and then you just have to get the times aligned. The polar file says what time it started recording, so you can easily add a time value to every reading based on the recording interval UNLESS you have it set to pause recording. If you do then I think it adds stamps somewhere saying stop and start times, but I'm not quite sure. I plan to check this over the next couple of days. If not, then you could figure out how long any pauses were based on the GPS track.

The GPS is less likely to be recorded at a fixed time interval (it might be, but I don't know for sure and have been playing with .GPX files from my phone, which are very much not at a fixed interval) so you can use a VLOOKUP to pull the matching HRM data out for each GPX point.

If the clocks in both devices are synchronised and there is no pausing in the recording (or there are distinct stamps telling you the duration) then you should be able to line this up exactly. With pauses it might be a few seconds out, but more accuracy will involve greater effort on your part.

You can then save it as an XML file, and I expect you can import it back into the garmin framework to analyse if you want, but as I said I haven't tried that.

The ideal thing would be to have a macro that does all of that for you, so all you have to do is export the two files, open excel, press a button and show it the two files, and then have it turn up complete in your training log. I might write that macro one day, but would need matching files from a polar and a garmin. In the mean time, if anyone else wants to save me the effort by doing it themselves (or has already done it) then I would love a copy!

Cheers,
Rowan