A Guide to Running on the Treadmill
With the hot temps rising and no sign of leaving any time soon, it’s no surprise that many runners are hopping on the treadmill to keep up their training while avoiding heat exhaustion. You’ve tried to give those morning runs a try, but maybe that doesn’t work with your schedule or the conditions are still too extreme for your body to handle them right now to be doing all your runs outside. Whether you’re opting for the treadmill for easy miles or key workouts (sorry in advance if you’re doing a long run), there are some key things to know to help you get the most out of your indoor miles.
We’ll cover a lot here but the biggest takeaway we want you to walk away with is this: “Don’t trust the treadmill. Trust your body.”
How Treadmill Running Feels Different
Form Adjustments
Running on the treadmill is different from running outside, even if you’re doing the same mileage. You’re running on a moving belt and not your usual sidewalk, road, field or track, so your body is going to move a little differently during your run. Some people notice they “bounce” more or hold tension in the shoulders—especially without natural terrain changes to break things up. Studies on treadmill running have shown that there is an increased peak knee flexion during the swing phase and increased peak knee extension during initial contact. There’s also an increase in hip Range of Motion and decreased foot-ground angle at foot strike.
The moving belt also means your glutes and hamstrings might not fire as much as they do on pavement, your stride might feel a little shorter, ground contact time slightly longer and your cadence slightly higher.
This all sounds a bit complicated, but it’s simply saying that your stride is going to be a little different without you even noticing it. It’s generally not something to be concerned about (unless you do most of your runs on the treadmill), but something to be aware of nonetheless.
Perceived Effort
Treadmill runs can feel harder, even at slower paces. Without the visual cues of the road or trail, effort can creep up fast. The lack of airflow is part of that too. When you don’t have the wind in your face, your body works harder to stay cool, which can spike both your heart rate and perceived effort, even if your pace hasn’t changed. Adding in some powerful fans and air conditioning can help, but it’s still not quite the same.
That said, it’s still running. Your heart and lungs don’t know whether you’re logging miles inside or out. The aerobic benefits are real, your muscles are still working, and you can absolutely improve your fitness. It’s also a great tool if you’re coming back from injury or need to keep your training consistent during extreme weather.
Why You Shouldn’t Obsess Over the Pace
Here’s a big one: treadmill paces are often wrong. Most treadmills, especially ones in gyms, aren’t perfectly calibrated. Measuring and adjusting for accuracy is a detailed process (involving belt marks and a lot of math), and many machines gradually drift over time. Wrist-based GPS watches won’t help you here either—unless you’re using a foot pod or a calibrated indoor mode, they’re guessing at best (and even those can be challenging to get accurate results).
Instead, base your run off:
- Effort (RPE) – How does the run feel? This is something we should always be asking ourselves during a run anyway, and the treadmill is no different and perhaps more essential to do so. Just because you have the speed set at your suggested pace, doesn’t mean it’s the right intensity for this run. Listen to your body. If it doubt, err on the side of caution and run slightly more conservatively. Tune into your breathing and mental load, not the number on the screen.
- Heart Rate – This only applies to those with a reliable and accurate heart rate monitor such as a chest strap or armband (so not your wrist watch). If you know the type of run you are doing (easy, Tempo, threshold, VO2max etc.) then you should have a good idea of what your heart rate should be during this workout. Periodically check your heart rate throughout the run and adjust the speed of the treadmill to fine tune it (while also listening to your body). Remember it takes time for that heart rate to climb so those earlier reps should be on the lower end or even below your zones for that type of effort. If you are at the top of your range early on, it’s typically a sign you are going too hard.
As a rule of thumb: Don’t trust the treadmill. Trust your body.
Should You Do All Your Runs on the Treadmill?
Short answer? No.
While the treadmill is an amazing option when it’s dangerously hot (or freezing), you still want to get some outdoor runs in, especially if you’re training for a race that will be outdoors. Specificity of your training is important and we want to closely match the race day conditions, terrain, environment as best as we can through our training cycle. Running outside helps your body acclimate to the elements, teaches you how to handle terrain and elevation changes, and mentally prepares you for race-day conditions.
That doesn’t mean you have to do every run outdoors. Use the treadmill for some recovery days, easy efforts, or when the heat index is just too high to train safely. Save your key workouts—tempos, intervals, long runs—for the road or trail when conditions allow.
Do I Need to Set the treadmill Incline at 1%?
Ah, the famous 1% rule. The idea is that it mimics the effort of outdoor running by accounting for the lack of wind resistance. And sure, it’s not a bad guideline, but it’s not required either. Some people find that 0.5-1% feels more realistic. Others prefer to adjust based on feel or use the incline for added resistance or hill simulations.
Personally, I like setting mine at 0.5-1.0%. Physically, it helps keep my form in check. Mentally, it feels like I’m secretly getting stronger, climbing a baby hill the entire time without fully realizing it.
Bottom line: do what feels best for your body. Don’t get too caught up in numbers; form, comfort, and effort are what really matter.
Tips to Make Treadmill Running Less Miserable
Let’s be honest: treadmill runs can drag. But there are ways to make them more tolerable, even enjoyable:
- Throw on a TV show or podcast to pass the time
- Keep fluids and fuel within reach (yay for not carrying a handheld!)
- Use a fan or air conditioning to stay cool
- Try a guided workout or structured interval session to break up the monotony
- Focus on effort zones (RPE or heart rate) rather than pace
Common Questions We Hear
To finish off, we took in some questions from our Flow Motion running Team Members when it came to the treadmill. This article covers a bit, but there’s always going to be things we don’t think about or don’t have time to cover. Here’s the top 3 questions we had. If you have any other questions about running on the treadmill, we’d be happy to answer them for you!
“Should I log treadmill runs differently?”
For treadmill runs, it is especially important to leave those post run notes that give the coach some extra insight into the run since the coach cannot rely on the pace/speed data it provides and if you are running with a wrist based heart rate monitor they can’t use that either. Be sure to report how the run felt along with a 1-10 RPE score at minimum. Your coach is relying on your feedback!
“Can I do workouts like tempos or intervals on the treadmill?”
Yes, but be aware the pace might not be accurate. Know how the effort should feel and base your workout on that effort. If you have a reliable and accurate heart rate monitor from the armband or chest, then you can also use heart rate to guide you (ask your coach if you need help with this).
“What if the treadmill feels easier than outside?”
That’s common too! Some people thrive on the belt. Just be mindful that your race won’t have the same smooth, shock-absorbing surface and the specificity of your training is important too. If we are training for a race on the road, we want to have most of our miles done on the same or similar surface too if possible.
Final Word
Whether you love or hate it, treadmill running is a powerful ally, especially when the weather makes training outside unsafe or unbearable. The most important thing isn’t the number on the screen, it’s the effort, the consistency, and how your body feels. So run smart, stay cool, and remember: a mile is a mile, no matter where you log it. You’re still getting better, even if the pace doesn’t match your outdoor runs.
PMCID: PMC7069922, 18460996