In 2014, Julio Payes was working 80 hours a week at two full-time jobs. A permanent resident from Guatemala who came to the United States on a work visa, Payes labored in Emeryville, Calif., a city of roughly 12,000 residents and almost 22,000 jobs, sandwiched between Oakland and Berkeley. He began his day with the graveyard shift at a 24-hour McDonald’s, where he served burgers and fries from 10 p.m. to 6 a.m. Afterward he had two hours to rest and shower. Then he’d clock in at Aerotek, going anywhere the temp service sent him between 8 a.m. and 4 p.m. To stay awake, he loaded up on coffee and soda. Each job paid minimum wage.

“I felt like a zombie,” Payes told me. “No energy. Always sad.” Yet just to afford basic necessities, he had to work up to 16 hours a day, seven days a week. Back then, he and his mother and two siblings all shared a single, unfurnished room. They were a tight-knit family, but Payes’s work schedule kept him away. Once, his younger brother, Alexander, who was 8 at the time, told him he was saving money. “I want to buy one hour of your time,” Payes remembers his brother telling him. “How much for one hour to play with me?” Payes looked at his brother and wept. Not long after that, Payes fainted from exhaustion in the aisle of a grocery store. He was 24.

It was around that time when the Emeryville City Council began to reconsider the city’s minimum wage. Oakland had just passed a ballot initiative to increase its minimum from $9 to $12.25 an hour, and Emeryville set out to match it. Then the mayor, Ruth Atkin, began asking if her city could do more, recasting the city’s minimum wage into something closer to a living wage. When Payes caught wind of this possibility, he began to pray. He prayed during Sunday and Wednesday revival services, where he danced and shouted as the spirit moved him. He prayed in quiet moments at home. “God, he believes in justice,” he said. “I have faith. But I also have politics.”

Payes became active in the Fight for $15 political campaign, participating in marches and other shows of collective force. “The first time we did a strike, I felt very nervous,” he said. But when he showed up in his work uniform and saw a mass of fast-food workers, thousands strong, he found his voice. It felt like church.

The policymakers responded. On a historic Tuesday night in May 2015, the Emeryville City Council voted to raise the city’s minimum wage to about $16 an hour by 2019. It would amount to the highest minimum wage in the country, outpacing San Francisco’s and Seattle’s. Emeryville’s minimum for workplaces with 55 or fewer employees jumped to $13 an hour in 2016, then $14 an hour in 2017, then $15 an hour in 2018. On July 1 of this year, it will reach $16 an hour for all businesses.

Julio Payes works full-time as a room attendant at a hotel and part-time as a cashier at Burger King. Celeste Sloman for The New York Times

Payes now makes $15 an hour at Burger King and $15.69 at a large hotel, where he works as a room attendant. “It’s had a big impact on my life,” he said. Payes can now afford to work less, logging around 48 hours a week when things are slow and 60 hours when they aren’t. He gets more sleep and can now exercise with walks in the park. “I feel better,” he said simply.

For years, when American policymakers have debated the minimum wage, they have debated its effect on the labor market. Economists have gone around and around, rehashing the same questions about how wage bumps for the poorest workers could reduce employment, raise prices or curtail hours. What most didn’t ask was: When low-wage workers receive a pay increase, how does that affect their lives?

But recently, a small group of researchers scattered around the country have begun to pursue this long-neglected question, specifically looking into the public-health effects of a higher minimum wage. A 2011 national study showed that low-skilled workers reported fewer unmet medical needs in states with higher minimum-wage rates. In high-wage states, workers were better able to pay for the care they needed. In low-wage states, workers skipped medical appointments. Or consider the research on smoking. Big Tobacco has long targeted low-income communities, where three in four smokers in America now live, but studies have found strong evidence that increases to the minimum wage are associated with decreased rates of smoking among low-income workers. Higher wages ease the grind of poverty, freeing up people’s capacities to quit.

Some of the biggest beneficiaries of minimum wage increases are children. A 2017 study co-authored by Lindsey Bullinger, an assistant professor in the School of Public Policy at Georgia Institute of Technology, found that raising the minimum wage by $1 would reduce child-neglect reports by almost 10 percent. Higher wages allow parents working in the low-wage labor market to keep the lights on and the refrigerator stocked; failing to do so can court neglect charges. “These studies show the positive externalities of increasing the minimum wage on serious outcomes, like reducing child abuse,” Bullinger said, issuing an eloquent barb at economists’ obsession with the “negative externalities” of minimum-wage hikes.

The list goes on. Studies have linked higher minimum wages to decreases in low birth-weight babies, lower rates of teen alcohol consumption and declines in teen births. A 2016 study published in the American Journal of Public Health found that between roughly 2,800 and 5,500 premature deaths that occurred in New York City from 2008 to 2012 could have been prevented if the city’s minimum wage had been $15 an hour during that time, instead of a little over $7 an hour. That number represents up to one in 12 of all people who died prematurely in those five years. The chronic stress that accompanies poverty can be seen at the cellular level. It has been linked to a wide array of adverse conditions, from maternal health problems to tumor growth. Higher wages bring much-needed relief to poor workers. The lead author of the 2016 study, Tsu-Yu Tsao, a research director at the New York City Department of Health and Mental Hygiene, was “very surprised by the magnitude of the findings.” He is unaware of any drug on the market that comes close to having this big of an effect.

A $15 minimum wage is an antidepressant. It is a sleep aid. A diet. A stress reliever. It is a contraceptive, preventing teenage pregnancy. It prevents premature death. It shields children from neglect. But why? Poverty can be unrelenting, shame-inducing and exhausting. When people live so close to the bone, a small setback can quickly spiral into a major trauma. Being a few days behind on the rent can trigger a hefty late fee, which can lead to an eviction and homelessness. An unpaid traffic ticket can lead to a suspended license, which can cause people to lose their only means of transportation to work. In the same way, modest wage increases have a profound impact on people’s well-being and happiness. Poverty will never be ameliorated on the cheap. But this truth should not prevent us from acknowledging how powerfully workers respond to relatively small income boosts.

Dr. Margot Kushel, who directs the University of California, San Francisco Center for Vulnerable Populations. Celeste Sloman for The New York Times

“When the minimum wage goes up, I see it,” says Dr. Margot Kushel, who directs the University of California, San Francisco Center for Vulnerable Populations, which is based in a local hospital. San Francisco and surrounding cities raised the minimum wage to $15 an hour last July. When Kushel’s patients have a bit more money in their pockets, “they exercise more. They are less stressed and can quit smoking. Their mental health improves pretty dramatically. Their sleep gets better. And people start eating healthier almost immediately.” Kushel continued: “We will spend an incredible amount on a new heart drug. But if we increased wages by $1, we’d save more lives.”

Alexandria Cutler also works for a hospital. Two, actually: U.P.M.C. Western Psychiatric Hospital and U.P.M.C. Presbyterian Hospital, both in Pittsburgh. A 23-year-old black food service worker, Cutler helps to prepare and deliver meals to hundreds of hospital patients. “It’s important not to mess anything up,” she told me. “People have allergies or have had surgeries and have to eat something specific. Sometimes patients can’t have straws.”

To stretch her paycheck over all her bills, Cutler often opts for the “2 for $5” menu at McDonald’s. Her U.P.M.C. doctor has advised her to eat better, especially given that both her parents have high blood pressure, and her father has diabetes and gout to boot, but processed fast food doesn’t demand much money or thought, she explained.

But in January 2018, an accounting error accidentally raised Cutler’s hourly wage from $12.32 to $15.50. She figured she had earned the extra pay from picking up more shifts, and she took it straight to the grocery store. At first she didn’t think she’d like broccoli, but she did. “I tried fruits and vegetables,” she said. “I tried salads. I experimented with foods I’ve never eaten. And I felt much better.” Cutler’s temporary raise didn’t launch her into the middle class, but it did influence her behavior in ways that benefited her health.

When U.P.M.C. discovered the glitch in February, Cutler was summoned to the director’s office. She remembers being told: “You’ve been accidentally paid. All that money, it’s not yours.” Her employer dropped her wage to $13.68 and reclaimed the overage from her next paycheck. For Cutler, it was back to McDonald’s.

When UPMC reduced her paycheck, Cutler took on extra shifts to cover the loss. It wore her down. During one shift, she tried to lift a full pan of mashed potatoes from the hot box. The pan was too heavy, and both Cutler and the potatoes crashed to the floor, hurting her back. She limped to the emergency room, where she was given lidocaine patches and sent home on bed rest. The next morning she was in so much pain that her mother had to help her get dressed. She missed seven days of work, for which she was not compensated.

Alexandria Cutler works for two hospitals in Pittsburgh, helping to prepare and deliver meals to hundreds of patients. She earns $14.42 an hour. Celeste Sloman for The New York Times

“I really love my job,” said Cutler, who today earns $14.42 an hour and has joined a group of workers trying to form a union at U.P.M.C. “I feel like when they appreciate me, that makes me feel great. But when the pay is low, I feel that they don’t see us as valuable at all.”

A living minimum wage buys prescriptions and rest and broccoli, yes; but it also provides something less tangible. Low wages are an affront to basic dignity. They make people feel small, insignificant and powerless. Subjectively experiencing these feelings can have real health consequences beyond the material hardships of poverty. This is why the poor exhibit better executive control and a heightened willingness to participate in social services when they have been affirmed, making them feel more capable and proud. It is why patients who are treated with dignity by their health care provider are more likely to follow doctor’s orders, adhering to their medical care. When we feel seen and valued, we are more likely to tend to ourselves.

The stress of poverty can also burden the mind, causing us to make worse decisions and ignore our health. In a classic 1999 study, researchers asked one group of people to memorize a two-digit number and another to memorize a seven-digit number. The subjects were then asked to wait in a lobby, where they were offered cake and fruit. Their willpower strained, those trying to retain the seven-digit number chose the cake 50 percent more often. Sendhil Mullainathan and Eldar Shafir, authors of the insightful book “Scarcity: Why Having Too Little Means So Much,” call this “the bandwidth tax.” “Being poor,” they write, “reduces a person’s cognitive capacity more than going a full night without sleep.” When we are preoccupied by poverty, “we have less mind to give to the rest of life.”

After his wages were increased, Payes swapped all that coffee and soda for water and iced tea, an act of will that became easier to achieve as his working hours diminished and his cognitive load eased. He has opened a modest savings account for emergencies and now gets to spend more time with Alexander, often picking him up from school.

Millions of American workers aren’t so fortunate. In 2016, 2.2 million workers earned at or less than the federal minimum wage of $7.25 an hour, a wage that hasn’t budged in a decade. These poverty wages, according to a recent review in Preventive Medicine, “could be viewed as occupational hazards and could be a target for disease prevention and health promotion efforts.” From this perspective, there is little difference between low wages and workers’ being exposed to asbestos, harmful chemicals or cruel labor conditions. These toxins compromise the well-being of workers and their children. The reverse is also true. A higher minimum wage is powerful medicine.

“Before, I felt like a slave,” Payes said. “But now I feel, ¿Cómo se dice, más seguro?” Safer, he said. “I feel safer.”