Excessive Daytime Sleepiness—This Is Your Wake Up Call

Published on Nov 22, 2017
Medically reviewed by Mike Kalogiannis, MBA, PhD

Falling asleep at work? In class? Or in front of the TV? We’ve all had the experience of daytime sleepiness once in a while. Certainly most of us would benefit from improved sleep behaviours such as: maintaining a regular sleep schedule, not eating or drinking caffeinated or alcoholic beverages too close to bedtime, or creating a relaxing ritual like reading or meditating before falling asleep. But if you experience excessive daytime sleepiness even with healthy sleep habits, speak with your doctor about sleep disorders as a possible underlying cause.

Around 1.5 million Australians and over half a million New Zealanders suffer from some form of chronic sleep disorder. Insomnia is the most common, but there are other causes of daytime sleepiness and fatigue including sleep apnoea and narcolepsy.

Chronic Insomnia

Insomnia is the inability to fall asleep, stay asleep, or the tendency to wake early and not go back to sleep. Insomnia is considered chronic when a person has the condition for at least three nights a week for a month or longer. Insomnia may be caused by medical conditions such as depression, anxiety, chronic stress, menopause, or chronic pain. Your doctor may diagnose the disorder with a physical exam, medical history, sleep history, or he or she may want to speak with your bed partner. You may be asked to keep a sleep diary for a week or two to keep track of your sleep patterns, so you can report the problem accurately to your doctor.

Sleep Apnoea

Sleep apnoea is a serious and chronic disorder, causing a person to have one or more pauses in breathing while asleep. Sometimes breathing with sleep apnoea causes a loud snort or choking sound. Other signs and symptoms of sleep apnoea may include loud snoring, headache in the morning, dry mouth, or sore throat. Sleep apnoea can cause daytime fatigue, insomnia, and irritability. It is important to treat sleep apnoea because if left untreated, it can increase the risk for heart disease, stroke, diabetes and other health problems.

There are two types of sleep apnoea: obstructive (the more common form in which the throat muscle over-relaxes) and central (brain doesn’t send signals to the muscles that control breathing). Many people with sleep apnoea don’t know they have the condition because it occurs only while asleep.

Sleep apnoea is diagnosed most often in a sleep lab and can be treated with continuous positive airway pressure, otherwise called a CPAP machine. Other treatments include dental devices or surgery in severe cases of airway obstruction. Lifestyle changes, such as changing sleep position, weight loss, and improving sleep habits, can also help some people.


Narcolepsy is a sleep disorder caused by the brain’s inability to control a person’s sleep-wake cycle. People with narcolepsy experience periods of extreme daytime sleepiness and a telltale sign, known as sleep attacks. These sleep attacks can occur at any time (e.g., person falls asleep suddenly in the middle of talking, eating, or other daytime activities) and can last a few seconds to several minutes. Many people who experience these involuntary sleep attacks will not remember that they fell asleep, nor will they recall what they were doing when the attack occurred.

Fatigue and cataplexy (periods of loss of muscle tone brought on by strong emotion such as laughter) are common symptoms occurring in many people with narcolepsy. Other less common symptoms include hallucinations upon waking or falling asleep and temporary sleep paralysis.

It is a common misperception that people with narcolepsy spend more time asleep than someone without the condition. In fact, those with narcolepsy usually have poor sleep quality, including waking up frequently at night and other sleep disorders.

Narcolepsy may be more common in people with a family history of the disorder, but can occur in anyone. People with narcolepsy have low levels of a chemical in the brain, called hypocretin (or orexin), which regulates sleep and wakefulness. The reason for low hypocretin levels is not known; however, narcolepsy is linked to reported cases of head trauma, brain tumour, and other diseases affecting the brain.

Diagnosis of the disease usually involves overnight sleep monitoring in a sleep centre (polysomnogram [PLT]) or a daytime sleep test (Multiple Sleep Latency Test [MSLT]). Though there is no cure, narcolepsy may be managed with medicines to help control symptoms and with lifestyle changes.

Sleep Specialists

Sleep is essential to health, so if you experience chronic daytime sleepiness or other sleep problems, speak with your doctor. Since many sleep disorders have overlapping symptoms, which can be difficult to tell apart, your doctor may send you to a sleep specialist who will ask you specific questions about your sleep habits and perform the appropriate tests.

Mike Kalogiannis, PhD is a Senior Associate in the Publications Management Team in Pfizer Medical, and has conducted sleep research prior to coming to Pfizer.



  • 1. Deloitte Access Economics Re-awakening Australia The economic cost of sleep disorders in Australia, 2010. Accessed 9/2/2017.
  • 2. Ellis PM, Collings SCD. Mental Health in New Zealand from a Public Health Perspective. NZ Ministry of Health 1997. Accessed 9/2/2017.
External Resources

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