Username for your Polar Account is always your e-mail address. The same username and password is valid for polarpersonaltrainer.com, Polar product registration, Polar discussion forum and Newsletter registration.
You can change your e-mail address in Polar Account or in polarpersonaltrainer.com .
In polarpersonaltrainer.com place your mouse over your name next to the main menu and select Profile.
Changing your e-mail address will affect to your Polar Account immediately. This means that next time you need to use your new e-mail address to log in.