This article originally appeared in the San Francisco Chronicle on March 19, 2014.
Dozens of studies over the years have shown that people who watch the most TV exercise the least. But that may be changing. Treadmill runners across the country are streaming shows on their smartphones and tablets, and their workouts often last as long as an episode.
Netflix has jumped on the trend, launching its “Watch It While You Work It” campaign. The company posted a graphic on its Facebook page that breaks down the calories the average person can burn by exercising while watching its fare.
Take in a 22-minute episode of “How I Met Your Mother” on a treadmill, and Netflix says you can drop 152 calories. Burning through a whole season of “House of Cards” (661 minutes) while on an elliptical burns 10,047 calories.
But is watching video while you work out a good thing?
Maybe not, says Dr. Michael Fredericson, professor of sports medicine at Stanford University and team physician for several of the school’s sports teams. Although he’s in favor of anything that gets people to exercise more, he warns that running while you look down at a screen is poor form, and the distraction prevents you from focusing on your body.
“When you lean forward, you create an arch and hyperextension in your neck,” he says. “You may get a good cardio workout, but when you get off, you’ll be stiff in your upper body.”
Listening to music while you exercise might be a better option. Unlike TV or streaming video, many studies show that music can benefit a workout by distracting people from fatigue and elevating mood.
Fredericson said he even encourages people in his community running clinic to align their running cadence with songs that have 90 beats per minute. But he adds that the most serious runners, like those he works with on the Stanford track team, don’t train with media distractions. “They’re very focused on their bodies and the experience,” he said. “They have a goal in mind for every workout.”