Struggling with your sleep timing?

Circadian Rhythm Sleep Disorders: Advanced & Delayed Sleep-Wake Cycle Explained

Do you find yourself unable to sleep at night and struggling to wake up in the morning? Or do you feel sleepy very early in the evening and wake up too early? These may not just be bad habits—they could be due to a circadian rhythm sleep disorder.

What is Circadian Rhythm?

Your body has an internal “biological clock” that regulates sleep and wake cycles over a 24-hour period. This is called the circadian rhythm.

It is influenced by:

• Light and darkness

• Daily routine

• Hormones like melatonin

When this rhythm is disrupted, sleep problems occur.

What are Circadian Rhythm Sleep Disorders?

These are conditions where your internal body clock is out of sync with your desired or socially acceptable sleep schedule.

Two common types are:

• Delayed Sleep-Wake Phase Disorder (DSWPD)

• Advanced Sleep-Wake Phase Disorder (ASWPD)

  
  

Delayed Sleep-Wake Phase Disorder (DSWPD)

What is it?

In this condition, your sleep is delayed.

You may:

• Fall asleep very late (e.g., 2–4 AM)

• Have difficulty waking up in the morning

• Feel sleepy during the day

  
  

Who is at risk?

• Teenagers and young adults

• Night owls

• People with excessive screen use at night

Causes:

• Late-night light exposure (mobile/laptop)

• Irregular sleep schedule

• Reduced morning sunlight exposure

Management:

• Fixed sleep and wake time

• Morning sunlight exposure

• Avoid screens at night

• Melatonin (as prescribed)

• Gradual shifting of sleep schedule

Advanced Sleep-Wake Phase Disorder (ASWPD)

What is it?

In this condition, your sleep is shifted earlier than normal.

You may:

• Feel sleepy early evening (6–8 PM)

• Wake up very early (2–4 AM)

• Feel unable to stay awake at night

Who is at risk?

• Elderly individuals

• People with early morning routines

Causes:

• Ageing-related changes in circadian rhythm

• Reduced evening light exposure

Management:

• Evening light exposure

• Avoid early bedtime

• Maintain a consistent schedule

Key Differences

Feature	Delayed Sleep Phase	Advanced Sleep Phase
Sleep time	Late	Early
Wake time	Late	Early
Common in	Young people	Elderly

When Should You See a Doctor?

Consult a sleep specialist if:

• Your sleep timing interferes with daily life

• You cannot adjust your sleep schedule

• You feel excessive daytime sleepiness

  
  

Why is This Important?

Ignoring circadian rhythm disorders can lead to:

• Poor work performance

• Mood disturbances

• Increased risk of metabolic and cardiovascular diseases

Take Control of Your Body Clock

Your sleep timing is just as important as sleep duration. With proper guidance and simple lifestyle changes, circadian rhythm disorders can be effectively managed.

If you are struggling with your sleep schedule, a professional evaluation can help restore your natural rhythm.