Partneři - Lode.czPartneři - Lode.cz

SPS Praha
CERE
Loděnice Vltava

Úvod > Závodění


ELLEN MACARTHUR MANAGEMENT OF FATIGUE:
 
      SLEEP HIGHLIGHTS DURING THE EUROPE 1 NEW MAN STAR RACE
By Claudio Stampi

Two hours and 10 minutes of uninterrupted sleep, it was the one and only luxury she allowed herself for the past long, exhausting 14 days.

 
All other times she recharged her batteries by taking multiple naps as short as 7, and never longer than 80 minutes, for a total average of just 4 hrs 11 minutes of sleep per day. This is how Ellen MacArthur managed to lead the Europe 1 New Man Star Race for the better part of two weeks.
But Ellen?s attention on alertness management started
right from the very beginning. She was able to open the race relatively well rested, having logged an average of 7.5 hrs of sleep on the nights prior to June 4th. This is not an easy task and many competitors are not able to exercise this control. Anxiety, last minute preparations, media hype -- are just some of the many pre-race sources of stress. Starting with the right foot is important because the first few days into the race are usually the most tiring and difficult. Indeed, on Day 1, while negotiating congested shipping lanes, proximity to coast, and adjustment to the sea, she accumulated less than 4 hrs of sleep in a series of mini catnaps as short as 7 minutes, and never longer than 24 minutes. From the second day onwards she extended her total sleep to just above 4 hrs, a daily quota she would have to struggle maintaining for the rest of the race.

Ellen has two types of sleep. She either takes uninterrupted naps, mostly shorter than 55 minutes (36% of her total sleep time, see Figure 1), or she practices the ?napping cluster? technique she learned during our 8-month pre-race alertness management training. That is, breaking up a ?long? sleep into shorter naps. After sleeping for 15-30 minutes, she wakes up, quickly checks the boat and the weather, makes necessary adjustments, and then resumes her sleep. Awakenings are brief, 3 to 8 minutes, and you are never fully awake. On the other hand, this Stage one state of drowsiness is exactly what catapults you back into sleep in just a few seconds when you hit the bunk. Obviously there are limitations. In this state you can only perform simple and brief tasks, and you need to have all the safety precautions in place. Ellen?s napping clusters accounted for 37% of her total sleep, they had an average length of 92 minutes, 20% of that time occupied by active awakenings (Figure 1).

Ellen has also learned what are her most effective napping zones ? times of day and night when she is more vulnerable to sleepiness and fatigue, and when sleeping will be more effective than risking potentially costly mistakes. In Figure 2 we show Ellen?s ?circadian signature?, her most important sleep ?gates? during the Transat, virtually identical to what we had identified during her recent Cape Horn to Cowes solo delivery of Kingfisher (Figure 2, Circadian Signature):

● In the evening/night: her ideal sleep start times were between 19 and 01 hrs, local time, with a secondary peak 2 to 5. Between 22 and 23 hrs, Ellen was asleep for 45% of the time during the entire race, a remarkable example of how our brain clocks are so precise in keeping track of time, even when we are navigating through time zones -- not to mention all the other perils.
● In the morning: she has a sleep gate at around 8, followed by another at 11
● In the afternoon: her most important daytime gate to sleep -- between 13 and 16 hrs -- this is her best opportunity to catch up on Delta sleep (Stages 3 and 4, or deep sleep). This is why many of us are sensitive to siesta time. It is a natural biological cycle, omnipresent in nature: why not take good advantage of it when opportunities for sleep are so scarce?
● The forbidden zone to sleep: Yes, no matter how tired we are, it is very difficult to fall asleep in the early evening, and the window varies depending on whether we are morning or evening people. For Ellen, the no-sleep zone occurred around 17 hrs local, clearly visible in the chart.

Why do the timing and duration of a nap matter, especially for a solo sailor? Because when we fall asleep we gradually move through the lighter stages into Delta sleep ? the stage that appears to be essential for recuperation. A sleep-starved individual ? as solo sailors often are ? will reach this stage quickly. If we locate the time of day when we have the most affinity to nap, then we will naturally and more easily reach that point. And if we wake up after we have completed the slow wave phase ? rather than in the middle of it -- then we will have minimized sleep inertia and achieved the most benefit for the shortest time: more bang for the bucks, as it were.

To do this you need to know the last, most important -- and for us most challenging to establish ?piece of the puzzle: the ?napping signature?. Our aim here is to identify the hidden patterns. Because nap lengths are subject to a variety of factors, large amounts of data are needed to detect the ?ideal? duration(s) of a nap. By ideal we mean the shortest nap(s) that will provide the maximum recuperative effect and feeling. In Figure 3, we compare Ellen?s napping signature during this race, to her 30-day Cape Horn to Cowes solo delivery. The figure shows that 40% of her sleep time is made by naps 77 minutes in length on average. The remainder of her sleep is made by shorter naps with preferred average durations of 17, 35 or 45 minutes. As a clear indication that this was an extremely demanding competition, she totally sacrificed the longer naps that she had onboard Kingfisher in her Horn to Cowes passage.

In these highly competitive solo races, knowing when you need to rest before it becomes too late is the key to success, even if you have only a few minutes available, and even if that might cost you of a few miles. The temptation to just keep pushing is too high. Indeed, these races are won by avoiding breakdowns not only in your boat, but especially in yourself. Judging by these data and by her extraordinary performance, Ellen appears to have learned this lesson remarkably well.

--

Claudio Stampi is director of the Chronobiology Research Institute in Boston. A circumnavigator himself, Dr. Stampi is a world expert on sleep strategy for sailors. For the eight months prior to this race, he studied Ellen?s sleep patterns and coached her on how to maximize her fatigue management and performance at sea. During the race he provided her with a special sleep micro-computer (Actiwatch) worn on the wrist, enabling him to monitor Ellen?s sleep data via satellite link, from which this report is based.

The Chronobiology Research Institute conducts research on human alertness, performance, biological rhythms and sleep, and runs Alertness and Safety Assurance programs to minimize human error, promote safety, and enhance productivity in corporations and organizations involved with shift-work and round-the-clock operations.

For more information, contact:

Chronobiology Research Institute
18 Karen Rd.
Newton, MA-02468, USA
Phone: +1.617.244-6237
Fax: +1.603.368-6144
Email: Stampi@Harvarda.Harvard.Edu

www.kingfisherchallenges.com

<< Předchozí

Přehled článků

Následující >>