In reply to thepodge:
If clearing out old runs doesn't help, then check you've got the latest software installed.
Also, if it's a new-ish watch that you can download widgets, apps, fields, watchfaces, etc from Connect IQ, then remove all these, if any installed, to ensure there's no rogue developer code screwing things up. They generally just affect battery life if not coded well, but worth taking the watch back to basics.