Yeah it’s going to depend on your plan. If you have a Flexible Spending Account for healthcare, you might be able to use that as well. Of course an FSA/HSA is your own money, but at least it’s not taxed as income... so it’s something of a discount.
My employer provided plan has me submit attestations saying whether or not I’m a smoker (I’m not) and whether I get regular activity (I do). Smokers get billed an extra $30 a month or so. Once they asked if I wear a fitness tracker, but with the caveat that it is just for informational purposes and they not offering discounts for wearing one at this time.