BYDR. DANIEL L. JOHNSON

Fatigue, Exhaustion,and Somnolence

Sleepiness and fatigue are usually notcaused by lack of sleep.

Jim felt a bump, turned and instantlyencountered light sink. He groaned,turned back on course. Too much of thattoday! He began to doubt himself: couldhe still tell the difference between a tur-bulent bump and a thermal? Had he lostall judgment? It was that sort of a day:Clouds small and scattered, bases 3000agl, climb rates 0.5 to 1.5 kt in the ther-mals he'd found.

But...he'd managed 70 nm. On the oth-er hand, it took two hours. He imaginedthat a world champion could make thisflight without turning, zipping along byfeel and experience. He wondered, "Whyam I doing this?"

His flight computer provocatively saidhe had to find 11,000 ft of climb to fin-ish his task today, and unless the day gotstronger, that added up to almost twohours of thermaling; well, grinding, really.He felt his way along, getting lower andmaking mental note of mown hayfields.

He saw a nice wisp downwind of alarge field and flew past the field's down-wind side. A bump. A wrong turn. An-other bump. He wrapped up in a nice,steep bank, felt the glider lift and heardthe vario chirp happily. The vario wasbouncing as high as 2, the averager overone knot. Here was respite for another15 minutes or so, to get enough altitudeto permit some choice among the fewclouds ahead.

However, maybe today, choice was notwhat he really needed. Maybe he shouldjust leave his fate to the anemoi.

On a good day, Zephyrus and Boreas,the soaring-friendly gods, would spinhim up high and carry him far, but today,Argestes and Notes had been pretty muchin command: Southerly winds bring lowbases and weak lift. Which begs the ques-

tion, Why tempt the gods? When we're70 miles from home on a weak day, wehave the same slog back that got us out,only we're more tired, but an unplannedland out to lay down for a rest - attractivethough it might seem at the moment -does not make life easier.

As Jim got near cloud base, he felt over-whelmed by sleep. He struggled to keephis eyes open. It was the same sensationhe'd had years ago as the dawn began tobreak after he first drove all night, it hadtaken tremendous force of will to prop uphis eyelids and keep his attention on theroad. As he'd begun that climb, he'd felttired and discouraged, but now he felt ab-solutely somnolent. He decided to dropthe task and head for home.

He turned on the new course andlooked at the few clouds ahead to de-cide which was the most promising. Aninstant later - or was it an instant? - hefound himself in a gentle, descendingleft turn. He shook his head to fight thedrowsiness. The words, "benign spiralmode" somehow came to mind. He feltembarrassment.

"Why am I sleepy?" he wondered. Hetook a brief inventory of his recent life.He'd slept well last night, but the nightbefore he'd been up three times dealingwith a severe thunderstorm that includeda tornado warning, wind that put a treelimb on his roof, and a four-hour powerfailure. He wasn't sick, but he did have aslight sore throat this morning, come tothink of it.

He and his wife had taken a 20-milebike ride after breakfast this morning, buthe was used to that. Come to think of it,she had been a little tart while he walkedthrough the kitchen to the garage, "Well,I guess /'// be mowing the lawn this af-ternoon." What? It could wait! The skywould not.

He had skipped lunch in order to as-semble, but had eaten a banana whilewaiting for tow, and had had some wa-ter already. He was glad to be away fromwork today - his boss, lately, had beenfinding fault with every little thing any ofhis underlings had done, except for homeruns. There was no telling when he'd jumpon someone. But everyone has this sort ofstress. Yet, today, what a pleasure to be ac-countable only to the glider.

Looking at the forecast and thesky that morning, nothing in life hadseemed as urgent or as important asbeing up amongst the clouds, climbingand gliding as far as the conditions al-lowed. Now, he was not only sleepy, butalso discouraged and fatigued. The longflight home seemed like a heavy burden.He decided to sell the glider. (An urgethat would pass, as transient as an in-testinal cramp, as soon as he had finalglide made.)

Why torpor?How many of us have ever felt like this

while glidering? Tired? Discouraged?Sleepy? Probably more than would admitto it, eh?

Why did Jim feel so bad? (Why mightwe feel so bad?) Jim had a number ofgood reasons to be fatigued, which feedsdespair and nourishes pessimism.

Typically several things conspire to-gether to cause any type of fatigue. Usual-ly, there are groups of things. It's difficultto judge the exact cause because nearlyeverything we do may cause fatigue, andthings happen in bunches. Here's a list ofsome important causes; Jim had prettymuch all of them:

• Motion-induced drowsiness (sopitesyndrome}

' Stress-induced social or psychologicalfatigue

• Low energy reserves (oxygen, fuel =hypoxia, diabetes, fasting, bonking, alco-hol-induced hypoglycemia)

• Infectious illness (viral, bacterial, etc.)• Physiological degradation (thirst, vol-

ume depletion, illness, acidosis)• Jet lag (shift work sleep disorder, etc.)• Poor quality sleep (central and ob-

structive sleep apnea, spousal snoring,etc.)

Today I want to focus on two of these:the sopite syndrome and disruption ofcircadian biorhythms (jet lag or shiftwork sleep disorder).

What is the sopite syndrome?The sopite syndrome is motion-induced

drowsiness and mood change. DuringWorld War II, it was observed that verymild motion sickness might exist only asapathy, loss of interest, or discouragement,yet until recently, it was not generally re-alized that sleepiness might be caused bymotion itself.

This reflects the narrow boundary be-tween sickness and health - after all,drowsiness is a normal response to mo-tion: after all we rock babies to sleep, ortake them for a ride in the car; and we donot think the babies are ill. It's a sicknessonly when we don't want it to happen,when it interferes with work or play.

"Regular" motion sickness includesnausea; and perhaps vomiting, cold sweats,sweating, pale skin, or excessive salivation.When motion sickness doesn't cause nau-sea, it may only cause lethargy. For exam-ple, some people on cruises spend a lot oftime sleeping. They blame everything butthe ship's motion. And, indeed, the othercauses may play a role, but...

Research in the last quarter of the 20thcentury showed that motion often causesdrowsiness when there's no other reasonfor it, even in fit, highly-trained pilots. Aclassic experiment put three or four pilotsin a big room that was turning at about4 revolutions per minute for a few days.There was memorable lassitude in manyof the pilots.

Jim fell asleep for a few seconds of sleepafter the top of his last thermal. This iscalled micro-deep. When we feel drowsyand are fighting to stay awake, we havemicro-sleeps of which we are not aware ofas keenly as the ones we detect by wakingup. This is a danger to drivers and pilots -if I maybe so annoying as to point out theobvious — and it's scary. It's scary to thepassengers, at least; and I hope it's scaryto the driver.

Treating sopite syndromeI've had a lot of experience with this, I

hate to say, and there are three things tobe done:

• First, try to eliminate other causes offatigue.

• Second, fly a lot. All motion sicknessattenuates with repeated exposure. BobHoover, the famous pilot, tells of beingvery prone to it when he was young, anddiscovered that daily aerobatics was a de-lightful cure.

• Third, caffeine. Early in the season, Itake one water bottle full of cold-presscoffee and drink that first. Or I buy caf-feinated Shot Bloks™ and eat three, oneabout every 30 minutes. Be careful ofenergy drinks; some have huge doses ofcaffeine

• a cup of coffee has about 80 mg.Don't get a prescription from your doctorfor modafmil (Provigil®) or armodafinil(Nuvigil®). These have the advantage ofnot causing heart palpitations, increasedblood pressure, or emotional irritabil-

ity that caffeine sometimes causes. But,they are not EAA-approved for pilots!The FAA requires that pilots refrain fromflight duties for 45 days after the last useof either of these medications. (No, I don'tknow why. But the FAA does base thesethings on performance testing.)

Orcadian DisruptionAnything at all that disturbs our nor-

mal regular sleep times will cause this,such as Jim's thunderstorm. This was firstcalled "jet lag" in the 1960s, after rapid

international travel became common-place. Before that it was called "mother-hood," caused by the infant waking upevery two hours.

Its current name is Shift Work Sleep Dis-order because this most common and im-portant. It disrupts lives and families andfosters injury at work.

If you want to know more about this,read the inset on time-shift sleep disorder.

What is fatigue, anyway?We have many related words to de-

scribe varieties of fatigue; torpor, lassi-tude, or despond, all of which involve theabsence of vivacity, zip, ginger, bounce, ordash.

There is "mental" fatigue from sustainedand difficult brain work; "emotional" fa-tigue from social stress or personal fail-ure. There is physical exhaustion from ef-fort, and the "bonk" of prolonged workwhen muscle and liver glycogen stores aredepleted.

Ironically, one activity can rejuvenate usfrom the exhaustion of another. Physicalexercise can get rid of pain or emotionalexhaustion. Intellectual challenge can res-

cue us from lassitude or torpor. Playingwith our children can help make workburnout disappear, and so on.

The causes of fatigue are too many toencompass in this short essay, as everymetabolic, hormonal, or mental abnor-mality can create weariness. Infections,medications, and food can make us tired.

What to do?The reason we have to examine our-

selves is that the best way of alleviatingfatigue is to understand what got us there,and fix that.

In flight, there are really only a fewthings we can do, each of which requiresplanning for the need:

• land• drink• eat• put on oxygen• fly straight and level for a while (ei-

ther 'dophining' or circling can cause mo-tion sickness).

Sleepiness is different from other fatiguestates. In my experience, it usually stemsfrom one of three things:

• disturbed or poor-quality sleep;

• motion (sopite syndrome); or• psychological stress.My experience is that recovery is very

fast if the cause is psychological stress,as soon as we escape from it and engageour minds in something good; and thatrecovery from motion-induced sleepinessis also quick if we stop the motion thatcaused it. Flying straight and level re-solves my own sleepiness in minutes.

Disturbed sleep can be caused by fac-tors external to us, such as a snoringroommate, the telephone, a baby, workduties, noises intruding from outdoors,and so on. I remember a night in a newhotel that was fine until the fire alarmwent off every three minutes for 20 min-utes. I doubt that anyone on that floorslept the rest of the night.

More important medically is that dis-turbed sleep can be due to physical abnor-malities. The Portly Pilot Syndrome

often includes obstructive sleep apnea,which can result in secondary physicaldisease, and makes the sopite syndromemore likely.

Fatigue means something's wrong.The most important thing is that if you

feel fatigued, weary, debilitated, sluggish,lassitude, or torpor, first, consider makinga "no-go" decision (or divert to a landing)until you've examined yourself to identifythe possible causes.

At altitude, mild hypoxia or dehydra-tion is probably most likely; failure tosnack may be the cause. On the ground,review the past couple of days for pos-sible causes, and fix what you can.

Inset: Fatigue checklist1: Hypoxia.2: Motion-induced drowsiness3: Dehydration or volume depletion4: Sleep disturbance.5: Illness6: Social stress7: Abnormal energy reserves and trans-

port (diabetes, fasting, hypoxia, anemia)8: Sedative medications9: Muscle exhaustion10: After-meal drowsiness11: Effort: physical, psychological,

metabolic, intellectual, or social.

Good additional readinghttp://www.ccjm.org/content/78/10/

675.full.pdf+html doi: 10.3949/ccjm.78a.l0083

"Jet lag and shift work sleep disorders:How to help reset the internal c/ock"BhanuKolla and Robert Auger, Cleveland Clin-ic Journal of Medicine October 2011 vol.78 No. 10 pp. 675-684.

http://archive.org/details/sopitesyndromeinOOflah

"Sopite Syndrome in operationalflight training David Flaherty, Na-val Postgraduate School, Dudley KnoxLibrary,September, 1998.

http://www.faa.gov/pilots/safety/pilotsafetybrochures/media/FatigueAviation.pdf

"Fatigue in Aviation", G.J. Salazar,Publication #OK-07-193, FAA-CAMI

Footnotes:The curse the the Internet: we can

look up interesting, distracting trivia.Thus we discover that the anemoi arethe Greek gods of the winds. Boreas isthe god of the north wind, Zephyrus ofthe west or northwest (depending onthe era), Notos the south, and Eurus theeast (sometimes, northeast). Argestes is

(in later eras) the god of the southwestwind.

This is all a little vague because therewasn't any textbook of meteorology un-til Aristotle filled that void by writingone. Meanwhile, wind names changedthrough the centuries. Yet whatever elsemight have annoyed the gods, chang-ing their wind assignments seems not tohave been a problem. Science was a lotmore entertaining when it involved gos-sipy stories about the gods.

In America, the endurance athlete issaid to "bonk" when glycogen stores inmuscle and liver are exhausted, and theathlete simply doesn't have the strengthto continue. In the British Empire, it'swhat might happen after the pretty girland the handsome man have a nice chatat the pub. I am not British.

For a long list of the caffeine levels of along list of beverages, http://www.energyfiend.com/the-cafFeine-database

I invented this syndrome; it's not anOfficial Disease. In Wisconsin, where Ilive, it's the Portly Packer Backer Dis-ease, from observing others exercise in-stead of committing it personally.