Do Treadmill Miles Count? A Run-Outside Coach's Honest Take

Full disclosure before we start: I don’t own a treadmill. I don’t have a gym membership. I’m a run-outside guy in pretty much any conditions.

And I still think treadmill miles count.

I’m not one of those purists who says you have to run a certain way, or can’t listen to music, or that indoor miles are somehow fake. Do what works for you and your life. Plenty of the runners I coach use a treadmill, and that’s totally fine with me. Here’s how I think about it.

Why I run outside (and when I wouldn’t)

My rule is simple: unless the conditions are actually dangerous, I go outside. Lightning, a tornado, a hurricane, an extreme blizzard, wind strong enough to bring trees down: those are the days to stay in. Outside of that, it’s a gear problem, not a weather problem. Have the right shoes and the right layers on your body, and you can handle a lot more than you think.

Running in rough conditions is also a chance to get a little more mentally tough. You might need to adjust your expectations for that run, slower in the heat, more careful on ice, but you still get it done.

That said, I’d be lying if I told you I never wish I had a treadmill. When it’s brutally hot, brutally cold, or just plain unappealing out, I get the appeal. Down the road, I’d probably use one as a way to soften the ride a little and control the conditions. Some great runners train on treadmills a lot for exactly that reason.

And don’t let anyone tell you the treadmill is the soft option. Running in place with nothing changing around you takes its own kind of mental toughness, unless you’ve got a movie going.

What the 1% incline rule actually fixes

The main physical difference between the treadmill and the road is wind resistance. On a treadmill, you’re not actually moving through space, so you’re not pushing through air. That makes the same pace a little bit easier indoors.

That’s where the familiar “set it to 1% incline” advice comes from. The idea traces back to a 1996 study by Jones and Doust, which found that a 1% grade best made up for the missing air resistance. A little incline makes treadmill effort more like running on flat ground outside.

Here’s the part that usually gets left out: air resistance grows with speed. At easy paces there’s not much to make up for. The correction matters most when you’re moving fast, at tempo and race paces.

When to skip the incline

One percent isn’t much, but it isn’t nothing either. If you’re dealing with an Achilles issue, or anything else where you’ve been told to stay off hills, be careful about setting a constant incline. Even a small grade, held for an hour, puts extra load right where you don’t want it.

My take:

• Easy and recovery runs: 0% is close enough. Skip the incline unless you want the extra work.
• Tempo runs and race-pace work: 1% is a sensible default, as long as nothing in your lower legs is complaining.
• Achilles or calf issues: keep it flat until that’s settled.

Where the treadmill beats the road: pace work

This is the treadmill’s real superpower. If you want to run at your marathon pace, your 5K pace, or any pace at all, you just set it and the belt holds it.

Outside, pace work means constantly glancing at your watch, speeding up, slowing down, fighting hills and wind and GPS that drifts under trees. On a treadmill, you lock in the number and the only job left is to hang on. For workouts that live or die on hitting an exact pace, the treadmill is the better tool.

Add in the climate control, no heat, no cold, no wind, and it’s easy to see why it works so well for some runners.

Does treadmill pace count the same?

For training purposes, yes. Treat a treadmill mile like a road mile. If you want to be precise about the effort, use the incline for faster running, and let your perceived effort settle any doubt. A pace that feels like a 6 out of 10 is a 6 out of 10, indoors or out.

What matters is that the work gets done. A treadmill run that happens beats a perfect outdoor run that doesn’t.

Do the belt math once

Treadmills show speed. Your watch and your training plan talk in pace. The treadmill pace calculator converts between the two in mph or km/h, and shows what your incline setting does to your effective effort, so you can set the belt for your workout without doing math mid-run.