MISHAWAKA -

When we think of heart attack victims, we don't picture a 35-year-old woman who's active, loves running and has no health problems.

But it happened to Heidi Henson. She was the picture of health: a college athlete, an avid runner.

"I've run three marathons, probably 50 other races," Heidi says.

She and her husband Nat, and their three beautiful children (Abbie, 6, Nora, 2, and Max, 9 months) every bit the healthy, thriving family.

Until one day in February, when Heidi was picking up Abbie from school. Suddenly, Heidi felt all the classic symptoms:

"My left arm, my bicep, horrible pain there. My chest, I was nauseous," says Heidi. Her jaw and teeth hurt incredibly bad as well.

It was a heart attack.

"I didn't know what to do," she says. "I called Nat and said, 'I think I'm having a heart attack.' But I'm 35 and healthy, there was no reason to -- I didn't believe what I was saying."

Heidi drove herself to the hospital, where doctors confirmed the heart attack. Before surgery, they told Heidi to say goodbye her husband, just in case it was the last time.

"I remember taking the kids out of the room, and I remember thinking, I don't know if I'll ever see her again, I don't know if the kids are ever going to see her again," Nat says.

Doctors told the couple that Heidi had a condition called SCAD: Spontaneous Coronary Artery Dissection. It's an incredibly rare and little-known condition. Basically, the inner lining of Heidi's artery had torn, causing a blackage.

Experts say SCAD tends to target women who don't seem to have health issues, especially women who have just given birth or taken part in a high-energy physical activity.

"I was scared," Heidi says.

And the news got worse.

The next day, they learned Heidi was pregnant, after doctors had already told them it would be impossible to have another child due to her condition.

"To be told then that we were pregnant was literally the worst news we could get -- both for my health and for the baby," she says.

The couple initially planned to go through with the pregnancy. But after spending eight days at the Mayo Clinic in Minnesota, no physician gave them the green light.

"From what the doctors told us, for us to go through with the pregnancy, they used the 'catastrophic,'" Nat says.

The couple was forced to make the heartbreaking decision to terminate the pregnancy.

"It was an incredibly decision and it's not one we made lightly, and we'll feel bad about it forever," Heidi says.

Fast forward to four months later, and the family is healing together.

But Nat felt he couldn't let this happen to another family. He had to help somehow.

"He just turned to me and he had tears in his eyes, and he said, 'We've got to do something,' Heidi says. "He said, 'You're going to think I'm crazy.'"

Nat proposed going on a 1,300-mile bike ride from Chicago to Colorado to raise money and awareness for SCAD.

He, his brother-in-law, and a friend whose daughter also suffers from SCAD, will set out on July 26, biking about 100 miles per day. At the end of the two-week ride, the two will present a check to the Mayo Clinic with money they've raised to pay for more research on SCAD.

"It baffles you that when they're speculating it might be a leading cause of heart attacks among women, that they didn't know anything up until three years ago about it," Nat says.

Heidi says she's humbled by her husband's actions.

"It's one of the great things about doing this ride, is that some good is going to come out of that awful situation," she says.

To learn more about the Hensons and Nat's biking journey for SCAD research, or donate to their cause, visit www.heidisheart.org.

To learn more about SCAD, visit http://www.heart.org/HEARTORG/Conditions/HeartAttack/AboutHeartAttacks/Spontaneous-Coronary-Artery-Dissection-Not-Just-a-Heart-Attack_UCM_454434_Article.jsp.