[OPINION] Walking Time and the Insult of 140 Calories

We often make plans to spend an hour on the treadmill early in the morning or after the day’s work, whether at the local gym or at home in the basement. There is nothing particularly complicated about the plan because the hour itself is what was deliberately set aside for walking. By our ordinary understanding of everyday activity, the planned task is accomplished by the time the intended sixty minutes on the treadmill has been completed. However, contrary to the ordinary way we live our lives, there is often a wave of disappointment when the treadmill shows that only 140 calories were burned.

Suddenly, an hour that seemed substantial when we carved it out of the day, and nonetheless substantial while we were on the treadmill, somehow seems less impressive. The 140 calories on the treadmill screen begin to compete with the hour spent walking until the planned sixty minutes are subconsciously reinterpreted as an attempt to burn calories, thus making 140 calories look suspiciously depressing for the whole endeavor.

There is nothing wrong with knowing that a walk requires about 140 calories, and there is absolutely no problem with estimating the energy required for any given task. A calorie is a unit of energy, and walking requires energy just as other physical processes require energy in one form or another.

However, what is curious is the authority we give that number after the walk is over. This is particularly surprising because we routinely understand that measuring one characteristic of an event does not turn that measurement into the event itself. The amount of energy involved can therefore be perfectly real information without becoming the outcome that interests us or a measure of what the entire activity was worth. This distinction is evident throughout ordinary life, in metabolism as well as elsewhere.

Let’s consider a marathon runner approaching the finish line of a 26.2-mile race. The runner needed energy from the beginning of the race to the end, and evidently nobody can deny that energetic requirement, but energy alone does not tell us what the runner set out to accomplish. The distance of the marathon is known, the finish line is predetermined, and when the runner crosses it, we recognize the completion of the undertaking without first needing to know how many calories were expended along the way. Energy was necessary for every step, but the amount of energy involved did not become the marathon or determine whether the runner crossed the finish line.

A much more ordinary example is a carpenter. Cutting, lifting, measuring, hammering, and assembling materials require muscular work, with energy underlying every movement, but when we watch a carpenter working, our attention naturally follows what is being built. No one necessarily wonders about the energetic cost of driving each nail before deciding whether the nail was driven, and if somehow we discovered that the carpenter expended fewer calories than expected, it would in no way make the emerging structure less real. The energy requirement belongs to the work without replacing the work as the thing that interests us.

The same distinction is evident in the physical activity of a roofer who spends the day climbing, carrying materials, balancing, reaching, lifting, and fastening roofing materials into place. All of that activity requires energy, sometimes a considerable amount of it, but the homeowner waiting for the work to be completed is primarily interested in what is happening to the roof. If the work scheduled for the day has been completed, learning afterward that the roofer expended a particular number of calories does not alter what happened on top of the house.

We make the same observation when no human metabolism is involved. On a warm day, an air conditioner requires electrical energy to cool a room, but the reason we turn it on is that we want the room to become cooler and more comfortable. We can measure how much electricity the air conditioner uses, but that measurement is not the cooling of the room itself.

When darkness comes and we turn on a light, electrical energy is required, but our immediate interest is usually in the illumination that follows. We can certainly measure the amount of electricity used, but the measurement of the energy required to produce the light is not the illumination itself.

A marathon runner, a carpenter, a roofer, an air conditioner and a light bulb may appear to have very little in common, but they expose something that we understand almost instinctively. Energy is necessary for physical processes without automatically making the amount of energy involved the outcome that interests us.

This is not an argument against energy, because there could hardly be a physical world without energy and its transformations. Movement requires energy, electrical systems transfer energy, chemical reactions involve energy changes, and living organisms participate fully in this same physical universe. Human movement therefore has an energetic requirement whether a treadmill displays it or not, and whether the person moving has ever heard the word calorie.

The peculiar turn occurs when we bring this universal physical requirement into discussions of human metabolism and physical activity, where the amount of energy involved begins to receive undue attention compared with the way we ordinarily view other human endeavors. Instead of remaining just one measurable characteristic of an intended activity, calorie expenditure can become the score by which the activity itself is judged, to the point that walking for an hour can somehow feel inadequate if the number displayed afterward appears too small.

The person on the treadmill makes the peculiarity especially easy to see because the original target was straightforward. The intended plan was to walk for sixty minutes on the treadmill, and had the treadmill displayed nothing more than elapsed time, there would have been little confusion about whether the intended goal was completed.

The appearance of 140 calories does not change what happened during those sixty minutes, but it can change how the activity is interpreted. A number that appears small can make the completed hour feel small, particularly when food and physical activity are so frequently translated into calories that we become accustomed to asking how much exercise is required to burn off something we ate or how many calories a particular activity is worth.

If the marathon runner crossed the finish line, a calorie estimate would not shorten the 26.2 miles that had just been completed. Why, then, should the completed hour of walking become disappointing because an estimate of one characteristic of that hour happens to read 140 calories? Calories are doing exactly what units of energy are supposed to do, and energy remains necessary for walking just as it remains necessary for the work of the carpenter, the roofer and the marathon runner, or for the operation of the air conditioner and light bulb. The confusion begins only when the measurement is asked to tell us something larger than what it measured.

The treadmill therefore presents us with a curious reversal. We began with an activity that had an understandable target, completed that activity, and then allowed a measurement taken from the activity to decide retrospectively whether completing it was worthwhile.

The 140 calories on the treadmill display did not shorten the hour, erase the minutes already walked or somehow transform the completed activity into an incomplete one. Ultimately, 140 calories is real information. It just isn’t the walk.

The 140 calories never insulted the walk at all. We insulted the walk by asking 140 calories to tell us what the hour was worth.

Mukaila Kareem is a doctor of physiotherapy and founder of metabolichealthliteracy.com