Language and unit of measure are inherited from the mobile device regional settings to be consistent with all the other apps used.
PulseOn supported languages are: English, Spanish, French, German, Swedish and Finnish. If there is no language installed in the phone that is supported, the app will fall back to English with metric units of measure (km).
Depending on the operating system and it's version, there might not be a separate setting for the region, but is instead inferred from the language setting. In such cases, for example, English (US) or English (UK) will result in an English user interface and miles as unit of distance while English (Canada) or English (Ireland) will get you an English user interface and kilometres as unit of distance.