Meet Carmen, your new trainer

She’s a virtual coach with a winning track record and bilingual advantage

2021 Issue 1 Closing the gap

Regina Sosa’s coach was unusual but effective. Over the course of a year, coach Carmen spurred the 70-year-old San Jose resident to increase her daily steps from an average of 2,500 to 10,000. The unusual part? Carmen is a computer program.

“I’ve really enjoyed it and feel like I’ve gotten a lot out of it. Every day during the program, I just tried to get more and more steps because I knew that I was going to go in and report my progress to Carmen,” Sosa said.

Carmen, who speaks Spanish and English, seems to be a boon for sedentary people seeking to adopt healthier habits, according to a study led by Stanford Medicine professor Abby King, PhD, with lab manager Maria Ines Campero playing a critical role in its execution. The study’s 245 participants were between the ages of 50 and 87 and were primarily Latino. The team published the results in the November 2020 JAMA Internal Medicine.

“Adults who are around 50 and up tend to struggle with maintaining adequate physical activity,” said King, professor of epidemiology and population health and of medicine. “But this is an age when people can really benefit from even small amounts of regular physical activity. It’s important for lowering the risk of a number of diseases and health conditions, such as Type 2 diabetes and obesity, as well as helping to maintain cognitive function and well-being.”

Low-income Latino adults are at particular risk for inactivity, said King. It was one reason her team configured Carmen to offer her services in Spanish as well as English. And while King’s previous research shows physical activity advisers can help adults in midlife or older kick their physical activity habits into higher gear, training coaches can be expensive and time consuming. That’s where King thinks Carmen could help.

King and her team collaborated with 10 community centers in California’s Santa Clara and San Mateo counties, with half of the centers coaching through Carmen and half through human advisers. In all sessions, advisers asked about the participants’ progress toward meeting the nationally recommended goal of walking 150 minutes or more each week.

With Carmen, participants start their sessions by scanning an ID so the program can “remember” previous conversations and data to inform the new interaction. Carmen greets participants by name, asks how they’re doing and inquires about their progress. Like a human coach, she’s personable with her advisees, asking them, for example, about their weekends. During the holidays, Carmen even revealed her New Year’s resolution: to be less glitchy.

If participants meet their walking goals, Carmen encourages them: “Keep it up! Would you like to set higher goals next week?” If they fall short, Carmen asks what stood in the way. Participants respond by selecting answers on a touch screen.

People who were coached by Carmen increased their walking by an average of 154 minutes per week, the study showed. Participants coached by a human increased their walking by an average of 132 minutes per week.

King said the study is the second she knows of to demonstrate that a digital coach can be as effective as a human at helping people increase activity levels, and the first to demonstrate this in a non-English-speaking population.

“While we don’t have a way at present to offer Carmen to the general public, we are interested in exploring collaborations with companies and organizations that would help us make virtual advisers like Carmen a widely available, low-cost option,” said King. She hopes to expand Carmen’s reach internationally, particularly to Latin America.

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Hanae Armitage

Hanae Armitage is a science writer in the Office of Communications. Email her at

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