From Barefoot Labor to Harvard Desk: She Researches Why We Don't Move

I-Min Lee, a Harvard professor and epidemiologist, didn’t exactly grow up planning to become a guru of physical activity. In fact, most people in her childhood orbit in 1960s Malaysia worked physically demanding jobs outdoors or as domestics. Exercise wasn't a hobby; it was just... life. The goal for their kids? A nice, comfortable desk job.

Lee nailed that goal. She's now a professor at Harvard Medical School and the Harvard T.H. Chan School of Public Health. The irony, of course, is that her career is now dedicated to understanding the health risks of not moving. Because apparently, that's where we are now.

She's the brains behind the Harvard Alumni Health Study and the Women’s Health Study, with some 650 papers under her belt. Her work connects sitting on your rear to a whole host of fun things like heart disease, diabetes, and cancer. It also helped shape the 2008 and 2018 federal physical activity guidelines — so if you’ve ever wondered how many push-ups you should be doing, she probably had a hand in it.

Lee stumbled into this field by chance, after med school and a stint studying biostatistics. She met Ralph Paffenberger, an epidemiologist who'd started connecting exercise to heart health. Lee, for her doctorate, expanded his work to include women. And, perhaps to fit in at all those fitness conferences, she even started running herself. Because nothing says 'I belong here' like a bit of light jogging.

The Sedentary Epidemic and the 10,000-Step Myth

Here’s a sobering thought: only 24% of U.S. adults hit the federal guidelines for both aerobic and muscle-strengthening activity. A whopping 46% meet neither. Which, if you think about it, is a pretty solid explanation for why three out of four American adults have at least one chronic condition like heart disease, cancer, or diabetes. Many of which, you guessed it, can be caused or worsened by inactivity.

But here's where it gets interesting: wearable fitness trackers. These tiny tech marvels are letting scientists like Lee ask incredibly specific questions about movement that used to rely on people remembering how much they walked. (Spoiler: people are terrible at remembering how much they walked.)

Using this fresh data, Lee was one of the first to gently poke holes in the universally accepted “10,000 steps a day” mantra. A 2019 study in JAMA Internal Medicine found that older women who managed just 4,400 daily steps had a 41% lower mortality rate than their more sedentary counterparts. The benefits topped out around 7,500 steps. Later research backed it up: even an extra 500 to 1,000 steps can make a difference for inactive adults. Let that satisfying number sink in.

Lee finds this rather encouraging. Telling people “any little bit is better than doing nothing” is a far more effective motivator than a seemingly insurmountable 10,000-step peak. The goal now is to update federal guidelines to include step metrics, helping everyone find activity that suits their life. Because sometimes, the best way to get people moving is to tell them they don't have to be an Olympian to start.