As matérias que encontrei associam o termo "scared fit" a alguém que resolveu entrar em forma depois de levar um susto com a saúde.

Como é um título, propus algo não literal mas que transmita essa ideia.

https://www.scaredfit.com/about-me/

So he got moving. He bought a pair of Adidas, laced them up, and hit the streets of Queens, where he lived at the time, jogging as if his life depended on it. He kept it up, running in the first New York City Marathon in 1974. He finished a respectable 193 in a field of 450. By then he’d moved to New Jersey. That’s where he added road bicycling to his routine. He’s still at it, at age eighty-two. He’s a lean, fit 150 pounds and rides an average of 4,700 miles a year. He considers himself a success story, having been scared fit. He wants you to be scared fit, too.




https://www.ideafit.com/fitness-library/beating-holiday-bulg...

"To begin, tackle the single issue that contributes to the failure of most fitness plans--motivation. The idea, experts say, is to concentrate on issues other than diet, exercise, or even health. "What's your driving force? What do you want to achieve in life?" asks GillianHood-Gabrielson, a fitness coach and motivation expert who says that studies show people can't be "scared fit." Instead, it's looking forward to living better that keeps people moving."