JOE HARRIS KNEW he was in trouble, even though he was winning the Transat 2004, a masochistic 2,800-mile solo-sailing race from Plymouth, England, to Boston, Massachusetts. Harris, a 45-year-old Boston-based commercial real estate investor, was making his debut in the big leagues of solo sailing and was elated to be in the lead. But beneath the adrenaline, he was exhausted. For almost 24 hours, he had stayed on the deck of Wells Fargo-American Pioneer, his 50-foot sloop, driving it hard through big winds and steep waves—"on the hairy edge," as he would put it later.

Since the Transat's start, a week earlier, Harris had been subsisting on three to four hours of sleep a day, snatched mostly in 20-minute naps. But when he found himself in perfect sprinting conditions, with his first real chance to tear into the 100-mile gap between Wells Fargo and then-leader Kip Stone, on Artforms, his competitive instincts took over and he stopped sleeping altogether. Hour after hour, Harris ground out the miles. When the morning roll call came in, he had nosed in front.

Now he was faced with protecting a slim lead just as his brain and body were screaming for sleep. Harris fought to keep the boat moving as light winds settled over his stretch of the sea, but his coordination deteriorated into five-martini territory, and he started to pass out on his feet, crashing repeatedly to the deck. Finally, he surrendered and slept for two and a half hours while Wells Fargo went nowhere. When he awoke, the position report delivered the cruel news: Stone was back in the lead.

"I knew I had shot my bolt," Harris said. "I pushed myself past my limits."

MANAGING SLEEP deprivation is a critical skill in the solo-sailing racing game, and Harris—who finished second to Stone after another week of difficult conditions—knew he was risking a meltdown with his mad dash for the lead. Four months before the Transat, he had been to see Dr. Claudio Stampi, the 51-year-old sole proprietor of the Newton, Massachusetts-based Chronobiology Research Institute, which he founded in 1997 and which is dedicated to the highly refined art of achieving maximum performance on minimal sleep. Stampi, whom sailors often refer to as Dr. Sleep, is the go-to guru when you want to race sailboats alone across the ocean on ridiculously small amounts of shut-eye.

Stampi had become interested in chronobiology—the study of biological rhythms—as a young student at Italy's University of Bologna, from which he received a medical degree in 1977, a Ph.D. in biomedical engineering in 1983, and a degree in neurology the following year. He has been obsessed with the trade-off between sleep and human performance ever since, publishing more than 100 research papers on the topic and, in 1992, a book, called Why We Nap. Over the years, Stampi has attracted a diverse clientele, from NASA astronauts and long-haul truckers to jet-lagged CEOs. But his specialty is helping sleep-deprived solo sailors.

"Solo sailing is one of the best models of 24/7 activity, and brains and muscles are required," Stampi said one day at his home, from which he runs the institute. "If you sleep too much, you don't win. If you don't sleep enough, you break."

Stampi has been hanging around docks for the past 20 years, placing custom-designed sleep-tracking wrist monitors (which record movement over time) on more than 100 solo sailors. His untraditional research raised questions from scientific sticklers, but according to James Maas, a professor of psychology at Cornell University and a leading specialist in sleep deprivation and performance, Stampi's open-ocean work has been very useful. "People often wonder how these guys, or someone like Charles Lindbergh, do what they do," Maas says. "So any evidence we can get as to how people will react under extreme conditions on very little sleep adds tremendously to our understanding."