You can check the email address you used for registration in Firstbeat Life application Profile - Settings- Account view
If you are logged out from the application, you can check the email address by using the Forgot password? option on the login page. Enter your email address and press Send recovery code button. If the email has not been registered into Firstbeat Life, you will receive an error message.
If the email is recognized, the app will automatically guide you forward to changing the password. Please note that it is not necessary to change the password, you can go back to the login page by using phone's Back -option.
If you need any further help with this, don't hesitate to contact Firstbeat Support.