Dr Alex BartleMedical Director

Sleep Well Clinic

Christchurch

11:00 - 11:55 WS #113: Circadian Sleep Disorders

12:05 - 13:00 WS #125: Circadian Sleep Disorders (Repeated)

The Structure of Sleep

Circadian Rhythms

Circadian Rhythm disorders

- Delayed Sleep Phase Disorder

- Advanced Sleep Phase Disorder

- Irregular Sleep Phase Disorder

- Non-24hr Sleep Phase Disorder

Sleep investigations & treatments in General Practice

Overview

REM - Rapid Eye Movement NREM - Non-Rapid Eye Movement

Stages 1 and 2 light sleep Stages 3 and 4 deep sleep

90 -100 Minute sleep cycles. 4 – 5 cycles per night to feel refreshed

25% REM, 50% Stage 2 and 25% stages 3 and 4

Circadian Rhythms

Circa Dies = About a day

Controlled by

Internal body clock - The Suprachiasmatic Nucleus (SCN)

External environment cues – Zeitgebers (Time keepers)

Circadian Rhythms

Sleep / Wake cycle

24 - 25 hours if left free running

Controls sleep architecture

Varies with age

1 : 2 ratio

Circadian Rhythms

Controlled by:

• Internal Body Clock

o The Suprachiasmatic Nucleus (SCN)

o Melatonin

o Core body temperature

o Many hormonal fluctuations

• External Environment Cues ‘Zeitgebers’ (time keepers)

o Light

o Exercise

o Meal times

o Work schedule

Circadian Rhythms

Internal Body Clock

Temperature

Reflects the sleep wake cycle

Association with melatonin secretion

Circadian Rhythms

Internal Body Clock

Growth Hormone

Maximum at night in non REM

Crucial for healing, growth and immunity

Circadian Rhythms

Internal Body Clock

Cortisol

Rises in the morning

Increases blood pressure and alertness

Testosterone

Higher over night and in the morning

Circadian Rhythms

Internal Body Clock

Melatonin

Endogenous (our own) is more effective than

exogenous (tablets)

Related to temperature and sleep

Tablets (0.5mg) are most effective at altering the

sleep phase when taken 4 – 6hrs before sleep

Circadian Rhythms

External Environmental Cues

Light - Direct effect on the SCN

The most alerting

Antidepressant

Can alter sleep / wake cycle

Exercise - Alerting

May compliment or inhibit the effect of

light

Circadian Rhythms

External Environmental Cues

Temperature - Environmental temperature can be

used to enhance or inhibit sleep

Feeding - Affects Gastric acid

Affects bowel motility

Stimulants / sedatives

Inhibition of gastric healing

Circadian Rhythms

External Environmental Cues

Social Stimulus

Daytime and night-time behaviour

Shiftwork

Jet lag

Work / play

“Rituals”

Circadian Rhythms

Internal Circadian Controls (Endogenous)

These have their own cycle, but can be modified

by:

External Circadian Controls (Exogenous)

These can be manipulated

Circadian Sleep/Wake Disorders

- Delayed Sleep Phase Disorder

- Advanced Sleep Phase Disorder

- Irregular Sleep Phase Disorder

- Non-24hr sleep Phase Disorder

Circadian Sleep/Wake Disorders

Delayed Sleep Phase Disorder (Night Owl)

- The most commons Sleep Phase Disorder

- Physiological delay (in Adolescents)

- ‘Social Jet Lag’ (esp.in Adolescents)

- Typically persistent 2hrs+ phase shift.

- Both sleep onset and morning waking are delayed

Prevalence:

• In Adolescence: 7.0%

• In Middle Age: 0.7%

• In a Sleep Disorders Clinic: > 17.0%

Delayed Sleep Phase Syndrome

Circadian Sleep/Wake Disorders

Delayed Sleep Phase Disorder (Night Owl)

Treatment:-

1. Chronotherapy

2. Slow advancement of the sleep/wake cycle

(See Adolescent sleep)

3. Use of timed morning light exposure

and evening darkness

Circadian Sleep/Wake Disorders

Advanced Sleep Phase Disorder (Larks)

- More common in the elderly

- Slowly advancing sleep phase with age (and work)

- Excessive evening sleepiness

- “Sleep Maintenance insomnia”

Circadian Sleep/Wake Disorders

Advanced Sleep Phase Disorder (Larks)

Treatment :-

- Reassurance.

- Timed evening light exposure and morning dark

- Evening exercise

Circadian Sleep/Wake Disorders

Irregular Sleep Phase Disorder

- More common in Children and Adolescents

- More common with

Neurodevelopmental disorders (ASD) and

Brain injury (TBI & brain tumours)

- No defined Sleep/Wake cycle

- Falling asleep and waking at any time,

Total sleep time is not affected

- Poor consolidation of sleep

Circadian Sleep/Wake Disorders

Irregular Sleep Phase Disorder

Treatment :-

- Use of Melatonin at night and morning outside

light

- Morning stimulants if necessary

- Sleep hygiene and routine day and night

schedule

Circadian Sleep/Wake Disorders

Non-24hr Sleep Phase Disorder

- Lack of entrainment of the circadian pacemaker

- Associated with

- Blindness (esp. nerve damage or enucleation)

- Developmental / intellectual disability

- Short periods of alignment may occur

Circadian Sleep/Wake Disorders

Non-24hr Sleep Phase Disorder

- Treatment :-

- Evening Melatonin and Morning outside light

- Day and Night Routine,

especially exercise and meal times

Adolescent Sleep

How much sleep do they need?8½– 9¼ hrs

How much sleep do they get?

Only 15% reported getting 8½hrs sleep on

week nights

Factors Affecting Adolescent Sleep

Biological Influences

• Emotional development

• Psychological development

• Physical development

o hormonal changes

o somatic growth

o circadian rhythm changes

Circadian Rhythms

Important considerations:

• Teenager ‘buy-in’. Appeal to:

o Sporting ability

o Academic performance

o Vanity!

• Parent ‘buy-in’:

o Explanation of the process

o Construct a schedule

Circadian Rhythms

Two ‘behavioral’ treatment regimes:

1. Phase delay (chronotherapy)

2. Phase advancement

Circadian Rhythms

1. Phase delay:

Best for those with very severe DSP (>4am)

o Delay bed time and wake time by 3 hours every night

until target sleep time is reached

o Allow no more than 8 hours ‘sleep opportunity’

ie 4am ------------------ 12midday

7am ------------------ 3pm

10am ------------------ 6pm etc

o Difficult to manage in a family environment

Circadian Rhythms

2. Phase advancement:

Best for those with less severe DSP

o Go to bed when sleepy

o Advance bed time and wake time by 15 minutes every

night until target sleep time is reached

o Allow no more than 8 hours ‘sleep opportunity’

ie 2:00am ------------------ 10:00am

1:45am ------------------ 9:45am

1:30am ------------------ 9:30am etc

o Easier to manage in a family environment

Circadian Rhythms

Summary:

• Morning light

o Timing – after lowest core body temperature

o Intensity – the brighter the light the more rapid the effect

(outside is ideal)

o Duration – ideally at least ½ hour outside

(longer in dim light)

Circadian Rhythms

Summary:

• Evening darkness

o Dim the lights in the evening

o Avoid electronic media for at least two hours before bed

o Use ‘blue blocking’ glasses in the evening

o Avoid caffeine in the afternoon and evening

o Avoid vigorous exercise within 4 hours of bedtime

Circadian Rhythms

• Melatonin:

o Produced in the Pineal gland

o Has a number of physiological functions

o Responsible for peripheral vasodilation

(consequent fall in core body temperature)

From: The journal of clinical endocrinology & metabolism; Salti,R; 85(6):2137-2144 (2000)

Circadian Rhythms

Summary

• Melatonin:

o Less effective than light manipulation

o Large doses (3mg – 5mg) tend to be sedative

o Small doses (0.3mg – 0.5mg) given 5-6 hours before

target sleep onset is effective

o Most effective when endogenous melatonin is not present

e.g. shiftwork / jet lag

o Results in peripheral vasodilation and fall in core body

temperature

Circadian Rhythms

Important considerations:

• Relaxation of the process will result in a rapid return to

the DSP

Late nights to bed on Friday and Saturday nights will result in difficulty

sleeping on Sunday night and difficulty getting up on Monday morning.

• Moving West will have immediate benefit but it won’t

last!

Circadian Rhythms

Important considerations:

• Remove all electronic media from the bedroom. The earlier

this regime is begun the better, especially in pre-teen years.

• Blue-blocking sunglasses in the evening

• No sunglasses in the morning

• Ensure morning light exposure is after the calculated lowest

core body temperature

Brief questionnaires:

- Epworth Sleepiness scale (General feeling of

Sleepiness in 8 situations)

- Stop-bang (Considering the possibility of OSA)

- Auckland Sleep Questionnaire (Is longer, but

covers many aspects of sleep)

- Morningness-Eveningness Questionnaire

The Epworth Sleepiness Scale

How likely are you to doze off or fall asleep in the following situations, in contrast to just

feeling tired?

This refers to your usual way of life in recent times.

Even if you have not done some of these things recently, try to work out how they

would have affected you.

Use the following scale to choose the most appropriate number for each situation:

0 = would never doze

1 = slight chance of dozing

2 = moderate chance of dozing

3 = high chance of dozing

It is important that you put a number (0 to 3) in each of the eight boxes.

Brief questions:

Example Questions from the MEQ

(19 Questions)

1. What time would you get up if you were entirely free to

plan your day?

2 What time would you go to bed if you were entirely free to

plan your day?

7. During the first half-hour after you wake up in the morning,

how tired do you feel?

12. If you got into bed at 11:00 PM, how tired would you be?

Thank You

Dr Alex Bartle

The SLEEP WELL ClinicsThroughout Mew Zealand