Jean Luc van den Heede is a legend among sailors. He has raced, single-handed, five times around the world and still holds the record of 122 days for a solo circumnavigation, east-to-west, against the prevailing winds.
Even legends must sleep.
In 1994, Jean Luc was nearing the end of the BOC Challenge leg between Cape Town and Sydney. He had sailed alone 6,700 nautical miles across the Southern Ocean. He was tacking the 60’ Vendee Enterprises through the Bass Strait between Australia and Tasmania, a body of water twice as wide as the English Channel and twice as rough, complicated by commercial traffic and strong currents.
“I had just passed Black Point and tacked. I had five minutes with nothing to do, so I put my head on a winch. A half hour later, when I woke up, I was on the beach.” He had been awake for 3 days.
In a long ocean race, managing sleep is as important as maintaining the boat. Sleep too little and you make mistakes. Sleep too long and you lose the race.
On July 1, Jean Luc, called JLH in France, will start his sixth solo circumnavigation. By his own word, he is a competitor, not an adventurer. He is in the race to win and he has long since learned what one sleep research team calls Wakefulness Made Good (WMG), analogous to the more familiar concept of Velocity Made Good (VMG). “WMG implies that a skipper needs to find an optimal balance between wakefulness (and thus sleep loss) and functional impairment (due to sleep loss), so as to sail most effectively.”
Wakefulness Made Good
The Golden Globe Race 2018 is roughly 30,000 nautical miles alone and without stopping.
In a race that demands sustained performance over weeks and months, the husbanding of a sailor’s available energy is probably more important than the total energy available. The youngest in the race Susie Goodall, an energetic 28-year-old.
JLH is 72 years old.
The sailors in the Golden Globe Race need to be awake to react to changes in wind and weather, hoisting or shortening sail, adjusting course, monitoring forecasts, maintaining the boat and themselves. They need to be awake to be competitive but sleep deprivation results in a lengthy list of symptoms: memory failure, difficulty thinking or concentrating, uncontrollable mood shifts, poor balance, and accidents among them.
The U.S. Army has a keen interest in the ability of sleep-deprived soldiers to keep fighting effectively. A study for the Walter Reed Army Institute of Research found the ability to do useful mental work declines by 25% for every successive 24 hours that an individual is awake.
“Sleep deprivation degrades the most complex mental functions, including the ability to understand, adapt, and plan under rapidly changing circumstances. In contrast, simple psychomotor performance and physical strength and endurance are unaffected.”
So, you can still do the work, you just can’t figure out what work to do.
A sleep deprivation study conducted by the University of Bonn found that, after 24 hours of sleep deprivation in healthy patients, researchers observed numerous symptoms otherwise attributed to psychosis or schizophrenia. Dr. Ulrich Ettinger, Department of Psychology, University of Bonn, said: “We were surprised at how pronounced and how wide the spectrum of schizophrenia-like symptoms was.” After a sleepless night, many of those who participated in the experiment had the impression they could read people’s thoughts. Dr. Ettinger actually recommended using sleep deprivation in medical experiments to simulate mental illness rather than drugs.
Solo ocean races have proved a useful setting to study the effects of sleep deprivation.
“If you sleep too much, you don’t win,” said Dr. Claudio Stampi, a chronobiologist. “If you don’t sleep enough, you break.” Chronobiology sounds like the study of time-traveling lifeforms. Prosaically, it’s about organisms’ adaptation to solar and lunar rhythms. Stampi has been studying the biological rhythms of sailors for decades.
He’s a huge fan of polyphasic sleep. Monophasic sleep is 7 or 8 hours of continuous sleep, the familiar kind. Biphasic divides the sleep period into halves. Polyphasic is a combination of short naps. One of Dr. Stampi’s field studies involving 99 sailors in single- and double-handed ocean races concluded the best performance results were obtained by those sailors napping for periods between 20 minutes and 1 hour, a total of 4.5 to 5.5 hours per day.
It seems we can easily adapt to less than 8 hours of sleep, 60% to 70% less, but no more. Remaining competitive requires at least 4.5 to 5.5 hours of sleep every 24 hours but diced into ultra-short, 20-minute naps. Less than 10 minutes seem to have no recuperative benefit. Longer than 20 but less than 80 minutes risks sleep inertia.
Asleep with Open Eyes
Sleep inertia is a lack of oxygen to the brain associated with stage 3 sleep and slow wave brain activity. You wake groggy, clumsy, unable to understand what’s going on. That’s not optimal when you’re racing across the Bay of Biscay or the Southern Ocean and you need to react instantly to some disaster on deck. It usually dissipates within 15 minutes but the impairment can be even more severe than sleep deprivation alone. A lot can happen in 15 minutes.
In the coming Golden Globe Race, a lot is likely to happen in 15 minutes.