Tracking steps on a treadmill desk?

The 'Indoor Walk' setting on the Apple Watch doesn't track steps properly when walking on a treadmill desk (because your hands don't move - I'm walking and typing right now.)

This would appear to be a standard problem.

Having to put your Apple Watch on your ankle shouldn't be the solution, that doesn't capture heart rate and is a hack.

Why hasn't apple added a 'treadmill desk' option to the 'Workout' app on the Apple Watch yet?

Are there any better solutions?

Using 'indoor bike' is another hack, but I don't think it would track steps either.

Apple needs to create a solution for this.