In reply to iusedtoclimb:
> Great right up and well done on 100 mile finish
> out of interest how did you record your route on Strava? What keeps battery life going for so long?
Thanks everyone. For recording on Strava I used my Garmin Fenix 5 which when not using the chest HRM is good for around 20-22 hours in normal mode. I took with me a portable battery to charge both my mobile and my watch on the go - I heard some HR watches can't record and charge at the same time but luckily the Garmin can.
It means I lost some of the HR data because I couldn't wear it on my wrist while charging but at least I got the whole track down.
Alternatively you can use UltraTrac mode which reduces the GPS sampling frequency to once a minute but obviously the accuracy goes down and I've never been happy with the results.