AN ARM AND A LEG

PHIL WAGNER is a man who believes in controlling his physiological responses, not letting them control him. Each night, he uses a technique called coherence training to harmonize his heart rate and breathing to maximize the restorative delta sleep phase. Upon rising, he spends the first three hours of his morning under red lights to stimulate the mitochondria in his retinas to produce more energy. This regimen allows him to limit his sleep to four hours and still feel refreshed. Wagner also fasts 18 hours a day so his stomach won’t distract him when he’s too busy to eat. “The mental constructs around eating are actually pretty interesting,” he says of the condition most of us simply think of as “hungry.”

Still, when Wagner, who runs a sports-tech company called Sparta Science in Silicon Valley, glanced at his phone after a meeting one morning in 2010 and saw he had nine missed calls from his wife, the reaction of his animal brain was a pure fight-or-flight adrenaline surge. Those calls could only mean something was terribly wrong at the hospital, where his newborn son was being treated.

Three-month-old Mason had been looking jaundiced, so that morning Wagner’s wife had taken him to the pediatrician. There, Mason was given a diagnosis of something called biliary atresia. A medical school graduate, Wagner knew it was serious. “They call it the silent killer,” he says. Mason was the one infant in 20,000 born without a bile duct. He needed emergency surgery to create one, and spent the next few months in the ICU while doctors waited to see if he would need a liver transplant.

The waiting carried an extra charge of anxiety for Wagner: He was not only a new father; he was also a new entrepreneur. As any parent would be, he was reluctant to leave his sick child’s side, but he was also barely a year and a half into running Sparta. After a slow start, the company had finally begun drawing a regular clientele of elite athletes, who had heard about Wagner’s