Louisa John poses for a portrait at her neighborhood Citi Bike station, July 7, 2017. Kholood Eid

Last summer, Louisa John suspected she may have been prediabetic. She had stiffness all over her body and was unhappy with her weight. When she saw her doctors at Interfaith Medical Center’s Bishop Orris G. Walker Jr. Health Care Center, in Crown Heights, they gave her the usual treatments for patients in her condition. Then they wrote her a prescription for a Citi Bike.

John was skeptical. The sixty-four-year-old had been scared of bicycles since one nearly ran her over when she was five. “I had a big gash,” she told the Voice. “It’s still there.”

Eventually, John, who lives on Social Security and other government assistance in Bed-Stuy, got on a Citi Bike and started riding laps around a nearby school three days a week. In combination with other treatments, she says, her Citi Bike rides have led to her losing about twenty pounds, and she is no longer considered prediabetic. “I have the energy to go and go,” she said.

John is the target audience for the New York City Department of Health’s pilot program known as Prescribe-a-Bike, [updated] where doctors offer a free one-year Citi Bike membership to patients as a way to encourage more daily activity. The initiative is trying to tackle a pernicious problem in the city: health inequity across neighborhoods, often less visible than housing shortages or transit access, but more troubling to public health officials.

“Certain neighborhoods are bearing the heaviest burden of disease…and this isn’t because of genetics,” said Dr. Torian Easterling, the assistant commissioner for the health department’s Brooklyn Health Action Center.

The health differences by neighborhood are indeed quite stark. For instance, the percentage of residents with diabetes in Chelsea and Greenwich Village is 4.8 percent, according to health department data; in the South Bronx and East New York, it’s 20 percent.

“When we enter into this conversation about inequities, we have to look at the mobility of people,” Dr. Easterling said.

The theory behind the Prescribe-a-Bike program is that increasing biking in areas like the Bronx or Brownsville provides health and financial benefits to residents, while giving them an alternative to the delay-plagued MTA.

“We’re thinking of Citi Bike as a potential health intervention,” said Phil Noyes, the health department’s director of research and evaluation.

Transportation Alternatives recently launched a Citi Bike for All campaign to expand bike share across the five boroughs, and residents of New York City Housing Authority buildings are eligible for discounted Citi Bike memberships. Bedford Stuyvesant Restoration has also launched several successful efforts to push the message that bike riding in the city can be for everyone.

“In truth, neighborhoods like Bed-Stuy are real transportation deserts,” said Tracey Capers, executive vice president of programs and organizational development at Bedford Stuyvesant Restoration. “Transportation is key to economic mobility.”

Prescribe-a-Bike began last August with a Centers for Disease Control and Prevention grant and a partnership with Interfaith’s Bishop Walker Health Care Center, which largely serves African Americans, Caribbean Americans, and Medicaid patients. If patients pass a physical, a doctor can “prescribe” a free Citi Bike membership. Patients get information on city biking rules and the health benefits of biking as little as fifteen minutes a day, plus a free helmet and reflector, and information about free classes and group bike rides that can help ease new cyclist jitters.

“At first they don’t want to do it,” said Alicia Fayton-Edwards, a care coordinator at the health center who also joined the program to treat her hypertension and now helps lead group rides. “You don’t see a lot of Afro-American cyclists. But you’re starting to see more and more.”

The majority of cyclists in New York City are indeed still white and live in largely higher-income neighborhoods, but the gap is narrowing. From 2007 to 2014, the amount of people riding bikes in high-poverty neighborhoods grew from 10 to 13 percent, according to a study the health department released last October. During the same time, the amount of white people who rode a bike at least once a month increased from 13 to 19 percent, while black ridership increased from 10 to 13 percent, and Latino ridership went from 13 to 17 percent. (A Citi Bike spokeswoman told me the company does not collect users’ demographic info.)

Since joining the program, Fayton-Edwards lost weight and her hypertension has decreased, and she feels more peaceful taking a bike rather than enduring a harried train commute. She uses the bike to supplement her commute to the clinic, parking at a nearby dock and walking the rest of the way.

About seventy people have signed up for the program so far, and about two-thirds of them are using the membership, said Maggie Veatch, who oversees the program. By the fall, the program will expand to Woodhull Medical Center in Bed-Stuy.

“The grand vision would be all doctors prescribe Citi Bike to their patients as a matter of course,” Veatch said.

Prescribe-a-Bike addresses the problem of people who can’t afford their own bike or don’t have room to store it in their small apartments. But it poses another set of hurdles too: Some low-income New Yorkers don’t have the bank cards required to use the system, even with a free account. Capers said Bedford Stuyvesant Restoration is working on solutions to this problem, offering financial and banking counseling to people who need it.

Prescribe-a-Bike also only offers a year of free Citi Bike; after that, users have to pay the $163 annual fee. Louisa John’s membership expires in August. She wants to keep riding after that, but she doesn’t know how she’ll be able to.

“I’m on a fixed income,” she said. “I don’t think I could afford to get [a bike] now.”

A health department spokeswoman acknowledged the program doesn’t have the funding to extend memberships beyond a year, but said that it has long-term goals: If Prescribe-a-Bike is a success, more employers, insurance companies, and other organizations may opt to subsidize bike share memberships for people.

Until their memberships expire, at least, participants like Fayton-Edwards said they’ve discovered a new perspective on the city from traveling above ground and behind handlebars.

“You kind of feel like you’re fitting in a little bit more in your community,” Fayton-Edwards said of biking. “You’re a part of your neighborhood, you’re a part of what’s going on.”