I’m told that a treadmill affords people the possibility of movement and exercise that would not be available because of weather or other circumstances. Yet every time I see someone walking or running, getting nowhere, I experience a poignant tug, somewhere between compassion and disdain that can’t be explained by the intellect.

We have a rich store of treadmill metaphors in our language: “stuck on a treadmill,” “the 9-5 treadmill,” “going nowhere, like being on a treadmill.” The dictionary offers many more, as well as this appealing Webster’s dictionary definition: a mill worked by persons treading on steps on the periphery of a wide wheel having a horizontal axis and used formerly in prison punishment.

Our endless love affair with technological innovation has now led to the Treadmill Desk. For $2500 or more, you can install a treadmill at your workstation, so you are walking in place while working. Proponents sing the praises of more mobility and weight loss. But let’s look at this a little more closely.

You are walking in place on a machine that doesn’t stop until you shut it off, while engaging in other tasks. That means you can’t possibly keep full attention on your task. It’s like texting while driving. You can do it, but at what cost? Something suffers – either the quality of your movement, or the quality of your work. Quality of my movement? Heck, I’m just walking, you say. Are you hitting the ground with each foot equally? How does your back and pelvis participate? Where is your head?

Your arms are an integral part of the function of walking. Yet they are now busy typing. Your eyes are part of your vestibular system, keeping you oriented to your environment. But now they’re staring at a screen. Your breath is regulated by your activity. But now, you get involved in a flaming email, your teeth are clenched, you hold your breath, and still the treadmill carries on!  It’s true, you can train your body to do multi-task in myriad ways, but where is your attention, really?

When you walk in the woods, or even down a busy city street, you are constantly paying attention to how you walk. Stepping over a boulder, veering around a baby stroller, hopping up onto a curb or on rocks across a stream. These varied movements actually help lubricate your joints and keep your spine flexible. On a treadmill, the motion, by necessity, is repetitive, using the same muscle groups over and over. You are also not experiencing the friction from the atmosphere. In fact, your atmosphere is more than likely recycled air. And what is our reptile brain thinking of this endless motion that goes nowhere?

Proponents of the office treadmill want you to think that walking like this is better for your health than a half hour of mindful walking outside. I think it’s part of the plot to keep us all prisoners. Do yourself a favor. Go for a walk, outside. Your body and mind will thank you.