Oct. 7, 2025, David Mitchell—As Natalie Stavas, MD, neared the end of the Boston Marathon for the fifth time in her running career, she saw and heard familiar things.
Thousands of fans were cheering. The finish line was in sight.
Then something unexpected.
Fireworks? How nice, she thought for a fleeting moment.
Two enormous booms were followed by screaming.
Spectators, not competitors, were running toward her.
“It was an inconceivable act of violence,” said Stavas, the mainstage speaker Oct. 7 at the Family Medicine Experience in Anaheim, California. “It shocked the nation and shook the city of Boston to its core.”
On that April day in 2013, she stood a few hundred meters from the finish line, facing a choice. Stavas, a pediatric resident and former trauma nurse at the time, could have stayed in the relative safety of where she was, run away from the sounds of a terrorist attack or run toward it.
Stavas sprinted into the chaos, but initially she didn’t get far. A police officer grabbed her by the shoulder and told her she was going the wrong way.
Stavas insisted that she could help.
She had to help.
Responders arrived to find hundreds of injured people and shattered store fronts. They raided damaged shops for supplies to make tourniquets. They triaged the wounded and tried to match severed limbs to the injured.
Stavas treated four people.
Three survived.
In the days and weeks that followed, Stavas was interviewed by numerous national and international media outlets.
“Reporters all asked the same question: ‘Why did you do that?’” she said. “I couldn’t come up with a good answer.”
Stavas wondered if something was wrong with her. Later, she realized the media were asking the wrong question.
“How do we teach people that courage is the first instinct, not fear?” she said. “Chaos is an opportunity to do right by the world. Take action. Be a positive influence.”
Stavas’ parents once gave their hyperactive young daughter running shoes and told her to “run around the block” before doing her homework. In her rural Nebraska community, the block was a four-mile square.
No matter, Stavas was hooked.
“Something remarkable happened,” she said. “I loved running, and over time my mind started to change. I could come home and focus, and I enjoyed what I was doing.”
She didn’t realize at the time that exercise was triggering a release of dopamine.
“When our brains are under the influence of dopamine, we are more enthusiastic,” she said. “We can set goals and find meaning and purpose in a challenging world.”
After the Boston Marathon bombing, Stavas and others wanted to better understand why she made her choice. Using functional magnetic resonance imaging, researchers gave subjects scenarios where they had to step out of their comfort zones and be courageous and altruistic.
The part of the subjects’ brains that was most active was the amygdala, which regulates a person’s emotional response to fear.
“Our brains are wired to reward us for being courageous,” she said. “We are misconstruing the feeling of apprehension. It’s our body telling us you have what it takes. You can rise to the occasion.”
An academic adviser once told Stavas she would never get into her first-choice pediatric residency because “Harvard doesn’t take people from Nebraska.”
The adviser was half right. Before Stavas, the program had never accepted anyone from the Cornhusker State.
Stavas has strong opinions about the impossible. She was a volunteer with Sole Train, a Boston program that pairs high-risk youths with adult volunteers who encourage kids to set and achieve difficult goals. Participants gather to train at least once a week.
Stavas was paired with a 14-year-old boy who had spent most of his life in foster care. She gave him his first pair of running shoes and off he went.
The boy set a goal to run the Boston Marathon the first year he was eligible at 18.
“He showed up every practice for four years,” she said. “His life could have gone a very different way.”
It wasn’t easy, but the teen finished the marathon despite severe cramping. He passed out after the race, but not before asking Stavas one question..
“He said, ‘I can do anything I set my mind to, can’t I?’” Stavas recalled. “I said, ‘Yes you can.’ And down he went.”
Stavas also shared a study on two groups of women: One group was made up of long-term care givers of people with end-stage Alzheimer’s or other forms of dementia. The other group of women described their lives as “not stressful.”
(The researchers, Stavas said with a laugh, did not disclose where they found the latter group of women.)
The study examined the DNA and telomeres of the women and found that the DNA of the stressed women were not as healthy as that of women in the non-stressed group, with one notable exception.
A subset of the caregiver group had the healthiest DNA of all the women studied. Further investigation found those women considered their work a calling rather than a challenge. Their mindset made them—and their results—different.
“We can’t choose our situation,” Stavas said, “but we can choose how we experience a situation.”
A year after the Boston Marathon bombing, The Boston Globe gathered survivors, responders, families and city leaders at the finish line for a photograph.
“We didn’t know each other,” Stavas said. “But we realized how important we were to each other.”
Three people died at the scene of the bombing. Two hundred and seventy injured people were evacuated, mostly by volunteers.
“Every person who left alive stayed alive,” she said.
Stavas said if people commit to being curious and courageous, they can not only survive but thrive.
“Never underestimate the importance of your actions,” she said. “We don’t know what the ripple effect will be on our colleagues, communities and patients for years to come.”