Timezone is wrong
Note: This tip applies only to iPhone users.
If the timezone looks wrong in the graph on the Timeline Pane, you can try the following to reset the timezone:
1) In the "Settings" app on your phone: tap 'General' >> 'Date & Time.' Change to a different timezone.
2) Open the Cardiogram app.
3) Go back to Settings, change the timezone back to the correct one.
4) Re-open the Cardiogram app.