"Exercise means a more fit workforce that will access the medical plan less often," says Elliott, noting that research has shown that for every dollar spent on wellness, businesses can save several times that amount in health-care costs and productivity.
But to see a return on investment, Elliott says, businesses need to create a culture of wellness, and clothes alone can't do that. "You don't want to just say, 'It's Friday! You can wear sweats to work.' It'll get old quickly," he adds.
To make the idea stick, he'd also throw in a planned physical activity for offices to do together as a team — maybe a morning group walk. Then participants could be allowed to wear those clothes the rest of the day as an incentive.
People in workout gear probably won't limit their activity to just the one walk, says John Porcari, program director of the clinical exercise physiology program at the University of Wisconsin at La Crosse.
Back in 2004, Porcari helped lead a study on the benefits of wearing casual clothes to work. A group of 53 subjects wore pedometers both on typical days in the office and on days when they wore jeans. On average, participants took an extra 491 steps — an 8 percent increase — on the casual days.
"Typically, when they wear jeans, they also wear more comfortable shoes," says Porcari, who believes that societal standards of dress are hampering physical activity. "People tend to be sedentary. If we force them into high heels and ties, we are reinforcing that."
The findings got attention at the time, but Porcari isn't aware of any follow-up research. If he were to investigate the Workout Wear Friday principle, he knows just how he'd go about it. Instead of pedometers, he says, subjects could have accelerometers that capture more data. He'd also combine the numbers with a questionnaire to ask directly about the effects of clothing on mind-set and behavior.