Why Is The Treadmill So Much Harder?

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    Does anyone else find the treadmill to be quite a bit harder than running outside? Not just mentally, but physically. I don’t use the treadmill much, but I did last Thursday because the roads were icy. It was supposed to be an easy run. So I set it to a 1 percent incline and picked an effort that felt about the same as one of my normal easy runs. Without exaggeration, the treadmill pace was at least 3 minutes per mile slower than what it felt like. I even used Stryd for distance and pace, and it was within 2-3 second per mile of what the treadmill indicated.

    Even my heart rate was the same as it would have been at the usual easy run pace. For what it’s worth, I can’t even run as slow as what the treadmill indicated. If I’m really beat up and do a super easy run/walk, that’s about the same pace that I end up with. Has anyone else had the same experience?

    Matt Fitzgerald

    Your experience is not the norm but is also not unheard of. There are a lot of misconceptions about how treadmill running compares to overground running generally. Here’s a piece on the topic I wrote a number of years ago:



    Thanks! Great information. I can go entire years without running on the treadmill, so maybe the difference would be less extreme with more experience.


    Looking at my Garmin statistics, I see something that might help. For outdoor runs, my stride length is around .87 meters (give or take). On my last treadmill run, it was around .73 meters.


    Pretty much the exact thing for me. I just purchased a treadmill. Tried it today for a foundation run. I got my HR dialed in and completed the 40 minute run. My pace was actually 1 min+ slower than my outside pace would be.

    Not sure what to make of it or to even worry about it. I will only use it when road conditions are poor. I will use HR to gauge effort and call it a day.


    Make sure to have good ventilation in the room your treadmill is in. I’ve noticed that with bike indoor training, since I have a CO2 monitor on the desk, the CO2 levels rise quickly while doing exercise, and it gets harder for the body to absorb oxygen. Note that it even can be dangerous if the CO2 levels rise too much. So in short, make sure that the area is well ventilated. Of course this is just on top of the other effects of indoor training such as heat and lost momentum.


    100% agree about ventilation. Have the same experience. I bought an industrial fan and set it next to a window so that airflow goes directly from the window to me running on a treadmill. Running became easier after that. The problem comes in summer when it is hot and humid outside. I push myself to go outside then – there is no AC, but at least there is more oxygen.

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