What causes insomnia? - Dan Kwartler

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What keeps you up at night? Pondering deep questions? Excitement about a big trip? Stress about unfinished work? What if the very thing keeping you awake was stress about losing sleep? This seemingly unsolvable loop is at the heart of insomnia, the world’s most common sleep disorder. So what is insomnia? And is there any way to break the cycle? Dan Kwartler details the science of insomnia.

Lesson by Dan Kwartler, animation by Sharon Coleman.

What keeps you up at night?

Pondering deep questions?

Excitement about a big trip?

Or is it stress about unfinished work,

an upcoming test,

or a dreaded family gathering?

For many people, this stress is temporary,
as its cause is quickly resolved.

But what if the very thing keeping
you awake was stress about losing sleep?

This seemingly unsolvable loop
is at the heart of insomnia,

the world’s most common
sleep disorder.

Almost anything can cause
the occasional restless night -

a snoring partner,

physical pain,

or emotional distress.

And extreme sleep deprivation like jetlag
can throw off your biological clock,

wreaking havoc on your sleep schedule.

But in most cases, sleep deprivation
is short-term.

Eventually, exhaustion catches up
with all of us.

However, some long-term conditions
like respiratory disorders,

gastrointestinal problems,

and many others can overpower fatigue.

And as sleepless nights pile up,

the bedroom can start to carry
associations of restless nights

wracked with anxiety.

Come bedtime, insomniacs are stressed.

So stressed their brains hijack
the stress response system,

flooding the body with
fight-flight-or-freeze chemicals.

Cortisol and adrenocorticotropic hormones
course through the bloodstream,

increasing heart rate and blood pressure,

and jolting the body into hyperarousal.

In this condition, the brain is hunting
for potential threats,

making it impossible to ignore
any slight discomfort or nighttime noise.

And when insomniacs
finally do fall asleep,

the quality of their rest is compromised.

Our brain’s primary source of energy
is cerebral glucose,

and in healthy sleep, our metabolism slows
to conserve this glucose for waking hours.

But PET studies show the adrenaline
that prevents sleep for insomniacs

also speeds up their metabolisms.

While they sleep, their bodies
are working overtime,

burning through the brain’s supply
of energy-giving glucose.

This symptom of poor sleep leaves
insomniacs

waking in a state of exhaustion,
confusion, and stress,

which starts the
process all over again.

When these cycles of stress
and restlessness last several months,

they’re diagnosed as chronic insomnia.

And while insomnia rarely leads to death,

its chemical mechanisms are similar
to anxiety attacks

found in those experiencing depression
and anxiety.

So suffering from
any one of these conditions

increases your risk of
experiencing the other two.

Fortunately, there are ways to break
the cycle of sleeplessness.

Managing the stress that leads
to hyperarousal

is one of our best-understood treatments
for insomnia,

and good sleep practices can help rebuild
your relationship with bedtime.

Make sure your bedroom is dark
and comfortably cool

to minimize “threats” during hyperarousal.

Only use your bed for sleeping,

and if you’re restless,

leave the room and tire yourself out
with relaxing activities

like reading,

meditating,

or journaling.

Regulate your metabolism by setting
consistent resting and waking times

to help orient
your body’s biological clock.

This clock, or circadian rhythm,

is also sensitive to light,

so avoid bright lights at night

to help tell your body
that it’s time for sleep.

In addition to these practices,

some doctors prescribe medication
to aid sleep,

but there aren’t reliable medications
that help in all cases.

And over-the-counter sleeping pills
can be highly addictive,

leading to withdrawal
that worsens symptoms.

But before seeking any treatment,

make sure your sleeplessness
is actually due to insomnia.

Approximately 8% of patients diagnosed
with chronic insomnia

are actually suffering from a less common
genetic problem

called delayed sleep phase disorder,
or DSPD.

People with DSPD have a circadian rhythm
significantly longer than 24 hours,

putting their sleeping habits out
of sync with traditional sleeping hours.

So while they have difficulty
falling asleep at a typical bedtime,

it’s not due to increased stress.

And given the opportunity,

they can sleep comfortably
on their own delayed schedule.

Our sleeping and waking cycle
is a delicate balance,

and one that’s vital to maintain
for our physical and mental wellbeing.

For all these reasons,

it’s worth putting in some time
and effort

to sustain a stable bedtime routine,

but try not to lose any sleep over it.