How to use HRM-env event?

I've been doing some quick tests on my Bangle running 2v19. However, I'm not sure what the output of this event is supposed to mean. All I get when I run this is zeros. Is this expected functionality?

Bangle.setHRMPower(1);
Bangle.setOptions({hrmPushEnv:true});
Bangle.on('HRM-env', function(env) {
    console.log(env);
});