Here is a review of an article that I did several years ago for our club newsletter. You may find it interesting and the full article is avaliable from Blue Water Sailing, referanced at the end.
Dave
s/v ARIEL
SLEEP STRATEGY FOR AN OVERNIGHT CRUISE
by Dave Nance
Like so many other coastal cruisers, Lois and I have found that the most difficult part of a cruise has been the trip that requires one overnight sail. The adrenalin created by the excitement of an offshore sail keeps us both up and active and we are tired by the time night comes and nether of us can sleep. We have tried watch keeping from the outset with no avail. Neither of us can sleep effectively and one of us usually ends up staying awake for twenty four hours or longer. We both end up cranky, tired and prone to bad actions. Does any of this sound familiar?
In an article titled
The Sleeping Enemy in the June, 2006 issue of
Blue Water Sailing magazine, Erin Myers discusses what makes us snooze and how we, as sailors, can best strategize our sleeping. This article is based on research and studies by Dr. Claudio Stanpi. I have condensed Mr. Myers article here in the hope that it might help in the development of a sleep and watch system for overnight cruises.
Dr. Stampi, sleep guru and accomplished sailor, has a medical degree, a Ph.D. in biomedical engineering and a degree in neurology. He participated in two Whitbread races to gather data from crews and has worked with Ellen MacArthur, Mike Golding and Brad Van Liew among others in his study of sleep and the requirement to stay alert while working in intense situations. His conclusions can be applied to short cruises as well as long solo passages.
At the heart of Dr. Stampi’s theory is his finding that alertness and performance are determined less than how long you sleep and more by when you sleep. Adapting to what Stampi calls a “polyphasic” sleep pattern, where sleep is attained in a series of short naps, will result in greater alertness, performance and safety in sleep-deprived situations.
There are some broad patterns that will help a person develop a sleep regimen. Almost everyone has what Stampi calls a “forbidden zone” between 6 and 9 p.m. when it is difficult to fall asleep. Sleep pressure, or the desire to sleep, is high at about 3:30 p.m. as well as early morning between 5 and 7 a.m.
Stampi’s research found truth in the terms “morning lark” and “night owl”. One of the first steps to developing sleep regimens is to figure out into which term you fall. “Morning people (larks) usually require more regular routines than do evening people (owls). On the other hand, larks tend to feel refreshed after even brief naps, while owls require longer naps to feel satisfied” he wrote.
Ellen MacArthur is a lark and often wrote about sleep in 20-minute naps in the most intense parts of her voyages. Mike Golding is an owl and has a very different sleep strategy, rarely getting less than an hour of sleep in any nap.
Stampi’s sleeping experiments have shown that in situations of sleep deprivation, polyphasic sleep preserves more performance and alertness than monophasic sleep. Individuals sleeping for 30 minutes out of every four hours, for a daily total of three hours, performed better and were more alert than those receiving three hours of uninterrupted sleep. He suggests 20-minute naps because you don’t have enough time to get into a deep sleep, as well as 80-minute naps because you get into deep sleep and cycle out to lighter sleep. He cautions that 50-minute naps can be trickier because you might wake during deep sleep, leaving you feeling groggy with detrimental effects on alertness and performance.
The brain likes predictability, he points out. Making naps routine will help train the brain to prepare for a nap and then recover from one. For example, regularly brushing your teeth or reading before a nap can hypnotize your brain to enter sleep. Likewise, a cup of tea, putting on a harness or washing your face can become stimuli to transfer you from sleep to alertness.
It is also important to identify what Stampi calls “circuit breakers” in your system - things that will serve as a red flag to let you know that you are critically sleep deprived and your performance and decision making are severely impaired. For example, accidentally boiling a pot of seawater for tea should let you know that you are dangerously sleep deprived and should rest before making any drastic navigational decisions.
Stampi suggests a watch schedule for doublehandlers that consists of a shift system with flexibility. Each person would be responsible for a shift, but they can nap or do whatever is efficient with that shift. Flexible shifts should take advantage of instances when you are riding the crest of alertness and your partner is sleeping deeply.
The ideal crew is composed of one lark and one owl. Then you can divide the night into two shifts, with the owl taking the late night shift and the lark the wee hours of the morning. As a rule of thumb, it is most efficient to take the long period of sleep during the night and take shorter naps during the day.
While a polyphase sleep pattern might be the most efficient way to deal with sleep deprivation, there will still be detrimental effects on performance and alertness due to the sheer lack of sleep. For this, Stampi suggests the Sunday Strategy. His research found that when employing polyphasic sleep during lengthy periods, one episode of free-running sleep once a week allows the body to recuperate. This might be most realistic on doublehanded boats, where once a week each person can afford a long period to top off their sleep while their partner stands watch.
You can reed this article in its entirety and with all the technical and neurological explanations by ordering
Blue Water Sailing magazine, June 2006, volume 11, number 6, at
www.bwsailing.com.