How can I measure accurate indoor running distances using my Apple Watch?

Some times it’s correct (sort of) usually it isn’t. I ran 1.55 miles according to my treadmill. Watch reported 1.02

Yet when I went to health and see walking and running distance, it is correct. Other than walking from bedroom to basement, this are the only steps I took. Health reports as 1.5 miles.

[Re-Titled by Moderator]