NORTH & SOUTH| JUNE 2019| 85
different.Itmaybeassimpleasthe
brainfillingintimebetweenthebrief
awakeningsofnormalsleep,perceived
aswakefulnessbysomeonepredisposed
tothisformofinsomnia.”
SleepDeprivation
Insomniaandsleepdeprivationare
oftenconflated,saysLeschziner– but
theyareopposites.“Ifyoustudysome-
onewhoissleepdeprivedinthesleep
lab,theydozeoffveryquickly,and
whiletheyareawaketheyperform
poorlyintestsofvigilance.Instark
contrast,‘shortsleep’insomniacswill
behyper-vigilant,andwilltake longer
tofallasleepinthelab.”
HealthRisksofInsomnia
Whentheriskofconditionssuchashigh
bloodpressure,Alzheimer’sanddiabe-
tesareanalysedinpeoplewithinsom-
nia,saysLeschziner,thosewith“prop-
erlymeasured”shortperiodsofdeep
sleephavehigherrates,whilethose
sleepingsixhoursormorehavenoin -
creasedriskatall.Highbloodpressure
anddiabetesmayturnouttobelinked
tochronic,measurablyhighlevelsof
stresshormones(elevatedby-products
ofthesecanshowupinurine)thatcause
anintensestateofanxietycalledhyper-
arousal,preventingsleep.Thisisnot
sexualarousal,buta corrosiveformof
alertness, nervousness and vigilance.
historiesoftenrecorda happyending.
Thedoctorisa patientlistener,dogged
detective,andcomesacrossasanhonest
reporterofhisowntreatmentstrategies
andmistakes.Eachcasehistoryis
revealing,notonlyaboutthepatientand
thesciencebehindtheirproblem,but
also,inanalmostaccidentalway,ofthe
kindly,drolldoctor-writer.
“Aftera fewmorenightrides,Jackie
gavehermotorbikekeystoherlandlady
forsafekeeping,andlatersoldit.Shestill
missesherBSA250.‘Brilliantbike!You
canhearthatcomingformiles.’I tellher
it issurprisingthatit didnotwake her
up. ‘It is, isn’t it?’ she says.”
Can’t Sleep?
- Roughlya thirdofadultsreportperi-
odsofpoorsleep,makingit byfarthe
mostcommonsleepdisorder.About
onein 10 adultshasinsomniaserious
enoughtomakethemtiredandirritable
duringtheday.Itcanbea signofan
over-activethyroidgland,a sideeffectof
medication,orofissuessuchasanxiety
ordepression.Thelinkbetweensleep
andmentalhealthis poorly understood,
saysLeschziner. - Youmightwellbegettingbettersleep
thanyouthinkyouare.Eventhosewith
severelybrokensleepcanactuallybe
gettinga normalamountofrestorative
deep(stage3)sleep.“Weareoftenun-
reliablewitnessestoourownsleep.” - True“shortsleep”insomniacsoften
haveelevatedmarkersofstresshor-
monessuchascortisolandadrenalin
intheirurine.Thesehormonesindicate
“fightorflight”stressandfearprocesses.
Symptomscanincludea racingheartand
dilatedpupils.Thesepatientsareliterally
terrifiedoftheirbedroom.“Importantly,
thesechangesarenotseeninpeople
withinsomniawhoaregettinga reason-
ableamountof[deep]sleep.”
SleepStateMisperception
“Itisincrediblycommonafter[asleep
study]tohear“Isleptterriblythat
night”,althoughthestudywillshow
a decentnight’ssleepofsevenhours.
Thepersonisadamanttheyonlyslept
anhourortwo.Somethingaboutthe
way this person experiences sleep is
HENRY FUSELI: OIL PAINTING ‘THE NIGHTMARE’- 1781. GETTY IMAGES.
HowMuchSleepisEnough?
“Thisquestion,”saysLeschziner,“is
similartoasking,‘Whatisthenormal
heightfora 10-year-old?’IfI lookat
mydaughter’sclassphoto,thechildren
rangeinheighthugely,butallofthem
arenormal.Likewise,thereisa range
ofnormalsleeprequirements.Itde-
pendsonyourgenes,andthequality
ofyoursleep.Therightamountofsleep
isthenumberofhoursneededforyou
towakeuprefreshed and not sleepy
duringtheday.”
SleepTrackers
Ifyouaresleepyduringtheday,orneed
tocatchupintheweekend,youare
probablynotgettingenoughsleep,and
Leschzinersuspectsyouwon’tneed
a sleeptrackertoknowthis.“These
devicesareatpresentrelativelyinac-
curate.Applyfivedifferenttrackersto
yourarmandyouwillgetfivewidely
divergingestimatesofyoursleepdura-
tion.Ifyouarealreadyworriedabout
yoursleepbecauseyouhaveinsomnia,
thenconstantlytrackingyoursleepcan
intensifyyourobsessionwithyoursleep
andmaketheproblemworse.”Formost
people,hesays,sleepis a subjectiveex-
perience,anda trackertellingyouthat
yousleptpoorlywhenyouexpectedto
betoldyousleptwellcan“initselfhave
profoundeffectsonyour own percep-
tion of your sleep”. +
Englishneurologistand
sleepphysicianDrGuy
Leschzinerusesthis
18th-centurypainting
byHenryFuseliinhis
lecturestoillustrate
theterrifyingstate
called“sleepparalysis”.
Thisisa failuretowake
completelyfromthe
sleepstateassociated
withdreaming(REM
sleep),whilethemuscle
paralysisofsleepisstill
switchedon.Thereis
oftena “senseofbeing
pinneddown,havinga
weightontheirchest,
theinabilitytomove,
accompaniedbydeeply
disturbingvisionsof
people or ghosts...”