7.4 Circadian Rhythm Disoders

Circadian Rhythm Sleep Disorders

Circadian Rhythm Disorder

when your body’s internal clock is out of sync with societal expectations

Circadian Rhythm Disorders usually cause

• insomnia

• excessive sleepiness at the wrong time

• daytime fatigue

Types of circadian rhythm sleep disorders

• Delayed Sleep Phase Disorder (DSPS)

• Advanced Sleep Phase Disorder (ASPD)

• Shift Work Disorder

DSPS problems

• “Night Owl” Problem

• very late sleep schedule (3am-11am)

• can’t fall asleep and struggle to wake up in the morning

DSPS symptoms

• can’t fall asleep until late

• struggle to wake for school/ work

• feel very sleepy in the morning

• normal sleep quality, just shifted too late

why does DSPS happen (3)

• cicadian rhythm wants a later bedtime

• very common in teenagers

• can become a real issue when responsilities (like school) don’t match

ASPD problems

• “early bird” problem

• very early sleep schedule (6pm-2am)

• get super sleepy in the evening and wake up too early

ASPD symptoms

• can’t stay awake in the evening

• wake up way too early (and can’t fall back asleep)

• tired during the day

Possible causes of ASPD

• weaker body clock (SCN)

• lower melatonin production

• less exposure to light in the evening

Shift Work Disorder problems (SWD)

• “I work nights” problem

• you work night shifts or rotating shifts- confuses your circadian rhythm

SWD symptoms

• can’t sleep well during the day

• feel tired at work in the night

• insomnia + excessive sleepiness

Why is SWD so bad

• you’re awake when your body naturally wants to sleep

• sleep is light, short, and easily disturbed

• may get 1-4 hours less sleep than normal

risks of SWD

• sleep debt

• low alertness= more accidents

• worse when shifts rotate quickly (e.g. every few days)

• long-term health issues

Bright Light Therapy (Phototherapy)

helps to reset biological clock (SCN) using artificial light

how bright light therapy works

• you sit near a light box that mimics sunlight (at least 2500-10,000 lux)

• sessions last 15 minutes to 2 hours

• can be done reading or using your phone

when someone with DSPS should do BLT

use light early in the morning to shfit circadian rhythm earlier

when someone with ASPD should do BLT

use light in the evening/night to shift circadian rhythm later

when someone with SWD should do BLT

evening or before shift to help you stay alert at night