The following article will explain how to change the units of measurement for your stats on your Dashboard. You will also need to do this separately for your mobile stats and separately to display meters on your watch.
1) Log into your account on your dashboard. Click here to login to your account.
2) Click on 'your name' in the top right of the screen. From the options that appear, click on 'Account'.
3) Once on the account screen. Click on the drop down option under 'Units' and select 'Meters' from the options displayed.
4) Click on the 'Save all Details' button at the bottom right of the screen. This will save the change and update all the stats in your account to be in meters.