A recent article in Women's Health Magazine recommended that it is not important to pay attention to watts while exercising and that power output is only relevant for professional athletes. We disagree and wanted to explain why paying attention to watts, when the option is available, is the best metric to track.

Read the article in Women's Health Magazine.

Response from Allen Lim, PhD:

Dear Editor,

In a recent article titled, “decode your display,” it was stated that there was “no need to pay attention to watts or METS.” That “these are measures of power and energy that are only useful to elite athletes.” The irony of the statement is that in a world of information overload, the reality is that both elite athletes and health enthusiasts do and should pay attention to Watts because it is inherently simple, truly objective, and vastly more reliable for measuring exercise intensity than any other metric currently available.

Fundamentally, the only details that are needed to understand one’s workout on any machine are time and intensity — how long and how hard. Measuring power isn’t just a way to measure “how much electricity you’d produce if you were hooked up to a generator,” its the only real way to measure the external effort on the body and is really no more complicated than measuring the weight of a dumbbell with a scale. And because it is accurate enough to measure how much electricity one produces, when power (i.e., intensity) is factored in with time (i.e., length of workout), it is possible to get a real measure of the energy or calories one burns during exercise, not just some extrapolated or inferred estimate. After all, the simple physics of the holiday bulge comes down to a battle between calories in versus calories out — a fact that only plays out with accurate measurement tools.

With that in mind, the usefulness of watching power for anyone who exercises on a machine lies in the measure's ability to help keep things simple, real, and consistent — to help us learn and discern how hard "hard" really is.

Allen Lim, PhD