Sleep Apnea Definition: Obstructive, Central and Mixed

Author Name: Heidi Holvoet, PhD
Medical fact-check: Dr Leah Alexander, M.D., F.A.A.P.

Sleep apnea definition : it is a disorder that causes a child or adult to stop breathing for several moments (up to a full minute) when asleep. These breathing pauses happen several times a night (up to 100 times!) and can have drastic consequences.

There are three different types, based on the different causes, i.e. how the airway is being blocked: Obstructive Apnea, Central and Mixed or Complex Apnea (See below for definitions).

Sadly apnea, or also apnoea, is quite common : about 2-4% of all adults, and 1-3% of children would suffer from it. Worse, it often goes undiagnosed and untreated .

Note: this page gives a general overview and definitions: click through for specific pages on sleep apnea in children and babies .

Most people are not aware of their breathing problems at night: their sleep is disrupted due to the breathing pause but they seemingly go straight back to sleep (as a result most patients do not feel they were truly awake). However, they do not spend enough time in a deep sleep so they get very poor rest quality (not to mention that of their partner's or parents' who often wake up at each breathing gasp too!). During the breathing pause, there is reduced oxygen flow to the brain.

The most obvious side effects of apnea are daytime sleepiness and severe fatigue. But when untreated , it will also cause high blood pressure and other cardiovascular diseases. Frequent headaches, memory and concentration problems, excessive weight gain are all possible side effects too.

The good thing is that it can be diagnosed and that effective treatments do exist. If you often snore (loudly), are (lightly) overweight, feel very tired during the day, or have been told you gasp for breath at night sometimes, do check with your doctor!

High risk factors are: being male, being overweight and being 40+ years old. However, many kids, youngsters and women of any age have it too. There are a couple of pediatric conditions where sleep apnea is common: Down syndrome, craniofacial abnormalities and cerebral palsy. If you have such a diagnosis then it may be worth being extra vigilant for signs of apnea, and ask your pediatrician specifically about it.

Obstructive Sleep Apnea Definition (OSA)

This is the most common one. It is when the person's airway is blocked physically . What happens usually is that the soft tissue at the back of the throat collapses, obstructing the airway.

This closes the airway, until the person wakes up, gasping for breath and consciously opens the airway again.

This is the most common case and as good as the only type of sleep apnea in children .

Central Sleep Apnea Definition

In this case, there is no physical blocking of the airway but a brain signal failure . What happens is that the brain signal necessary to keep the airway muscles functioning, does not go through correctly.

This is the common type of sleep apnea in infants .

Mixed or Complex Sleep Apnea Definition

This is when the person has a combination of the two causes: there are breathing pauses due to a physical blocking of the airway and others due to a failed brain signal.

Mixed Sleep Apnea is typically seen in adults receiving treatment for obstructive sleep apnea, not in children.

According to a 2006 study [1] [2] , 84% of apnea cases are of the Obstructive type, 0,4% are purely Central. About 15% is the Mixed type.

Article Author: Heidi Holvoet, PhD - Founder, senior sleep consultant

Heidi Holvoet, PhD

Heidi Holvoet, PhD, is the founder of the Baby Sleep Advice website and movement, an award-winning author, baby & toddler sleep consultant with 15+ years experience as well as a certified lactation counselor.

Over the years, Heidi has received several awards inluding a Mom's Choice Award (MCA) and National Parenting Awards (NAPPA) for her Baby Sleep Advice website, programs and books. Also, Baby Sleep Advice was awarded "Most Trusted Infant's Sleep Solutions Company 2023" in the Benelux Enterprise Awards 2023.

Heidi continually conducts personal research and participates in continued education and in that way stays up to date with current scientific and pyschosocial infant care.

Association of Professional Sleep Consultants

She is also a member of the Association of Professional Sleep Consultants of which she was one of the earliest contributors. She obtained her PhD degree in physics at the University of Ghent in Belgium.

Heidi is passionate about helping babies and their parents sleep more and better, with her trademark approach that has been proven and praised time and again by parents worldwide to be effective and truly no-tears. Respect for you as a parent and your baby, is at the heart of Heidi's warm and kind support. Her approach always keeps in mind a baby's needs and abilities at any given age, is based on pediatric science and the most up to date knowledge in infant care and sleep science.

As well as the award-winning baby sleep programs, Heidi offers popular 1:1 consults and easy-access 30-minute SOS Sleep sessions.


[1] Complex Sleep Apnea Syndrome: Is It a Unique Clinical Syndrome? Timothy I. Morgenthaler, MD; Vadim Kagramanov, MD; Viktor Hanak, MD; Paul A. Decker, MS Sleep 2006;29(9):1203-1209.

[2] The 3 Types of Sleep Apnea Explained: Obstructive, Central, & Mixed Jennifer Hines,