In the event that the screen freezes or the screen is unresponsive you can reset the watch by following the below:
1) Turn the watch on by pressing the top left button.
2) Hold down the top left button for approximately 15-20 seconds until the screen goes blank.
3) Press the top left button once to turn the watch back on.
This should now have reset the watch successfully for you.
Please note that no data or saved settings will be lost following a reset.