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SleepTalk™: Dictionary of Terms

Published on November 14, 2022

8 minutes

Obstructive sleep apnea in adults - sleeping patient (female) 1

Circadian Rhythm: A daily cycle of biological activity based on a 24-hour period and influenced by regular variations in the environment, such as the alternation of night and day. Circadian rhythms include sleeping and waking in animals. The circadian rhythm, present in humans and most other animals, is generated by an internal clock that is synchronized to light-dark cycles and other cues in an organism’s environment.

Sleep Efficiency: This concept is calculated based on how much time you spend asleep after you turn the lights off and go to sleep.  85% is considered a normal rate.  If you are below, it means that you are spending time trying to fall asleep which affects the quality of your sleep.

Rapid Eye Movement (REM) Sleep: Typically making up 20-25% of a total night’s sleep, periods of REM sleep occur 3-5 times throughout the night. During REM sleep, heart rate and respiration speed up and become erratic, the eyes move quickly in different directions and intense dreaming occurs.  Many cases of OSA occur during this key sleep cycle.

Dreams: Dreams are a successive collection of mental images, ideas, emotions and physical sensations that occur involuntarily during sleep. Lasting between a few seconds and up to 30 minutes, dreams mainly occur during the Rapid Eye Movement (REM) stage of sleep.

Slow-Wave Sleep (SWS): SWS, also known as deep sleep, is the stage where mind and body activity decreases significantly during sleep. This sleep stage is important for physical healing and growth, as well as consolidating new memories from the day.

Melatonin: is a natural hormone that helps your body cycle between going to sleep and staying awake. Melatonin is secreted by the pineal gland, a pea sized gland located in the brain. Our Melatonin levels begin to rise in the evening and will stay high most of the night before dropping early morning. This hormone is also often referred to the hormone of darkness.

Obstructive Sleep Apnea (OSA): Obstructive Sleep Apnea is caused when the soft tissue walls of the throat collapse to the point where they block, or severely narrow, the upper airway during sleep.  OSA is characterized by repetitive pauses in breathing during sleep and can lead to low levels of oxygen in the blood, sleep deprivation or potentially other conditions such as heart disease.

Central Sleep Apnea: Central Sleep Apnea is a sleep-related disorder that causes you to momentarily stop breathing during sleep, and is usually associated with a reduction in blood oxygen saturation. Less common than Obstructive Sleep Apnea which is caused by upper airway obstruction, Central Sleep Apnea is the result of your brain not sending the proper signals to the muscles that control breathing.

Polysomnogram (PSG): A polysomnogram is a test that measures biophysical changes during sleep.  Its results are analyzed by a qualified sleep specialist to determine whether or not you have a sleep disorder.

AHI: The Apnea–Hypopnea Index is an index used to assess the severity of sleep apnea based on the total number of complete cessations (apnea) and partial obstructions (hypopnea) of breathing that occur per hour of sleep.

APAP: The Automatic Positive Airway Pressure unit measures resistance in a person’s breathing and automatically adjusts the amount of air pressure delivered breath-by-breath in order keep airways unobstructed.  Typically the same types of masks are used for APAP therapy as CPAP.

BPAP, or BiPAP: The Variable/BiLevel Positive Airway Pressure unit provides two levels of pressure; one for inhalation and one for exhalation, which typically improves comfort.  The same types of masks are used for BPAP therapy as CPAP.

CPAP: A Continuous Positive Airway Pressure unit is used for some people who suffer from OSA.  This type of machine provides a steady stream of air through a mask worn on the nose or mouth (or both), keeping the airway open and helping provide more restful sleep.

Sleep-Disordered Breathing (SDB): SDB describes a wide spectrum of sleep-related issues where a decrease of airflow (hypopnea) or complete cessation of airflow (apnea) occurs during sleep. SDB can sometimes be caused by an airway obstruction, and includes Snoring, Upper Airway Resistance Syndrome (UARS), Obstructive Sleep Apnea (OSA) and Central Sleep Apnea (CSA).

Ghrelin: the “hunger hormone”, is a peptide hormone produced by ghrelinergic cells in the gastrointestinal tract which functions as a neuropeptide in the central nervous system. Besides regulating appetite, ghrelin also plays a significant role in regulating the distribution and rate of use of energy.

Leptin: is a hormone made by adipose cells that helps to regulate energy balance by inhibiting hunger. Leptin is opposed by the actions of the hormone ghrelin, the “hunger hormone”. Both hormones act on receptors in the arcuate nucleus of the hypothalamus to regulate appetite to achieve energy homeostasis.

Electrocardiogram (EKG or ECG): An electrocardiogram is a test that analyzes the electrical activity of your heart. This test shows heart activity as line tracings on paper using a series of spikes and dips called waves.

Restless Leg Syndrome (RLS): Restless Leg Syndrome is a neurological disorder characterized by the constant urge to move the legs to stop uncomfortable or odd sensations. It can also affect the arms, torso, head and phantom limbs. RLS is considered a sleep disorder as it often interrupts sleep, and it differs from Periodic Limb Movement Disorder (PLMD) which is characterized by involuntary leg movements.

Lucid Dreaming: In a lucid dream, the dreamer is conscious to the fact that he or she is dreaming. Often times one experiencing a lucid dream can control their actions and even the environment within the dream.

Alzheimer’s Disease: Alzheimer’s Disease is a progressive deterioration of the brain that destroys memory and mental function. Alzheimer’s occurs in middle or old age, and is the most common cause of dementia.

Memory: Memory is the mental capacity for your brain to store and recall information. This information may include facts, events, impressions, people, and things learned or seen.

Daylight Saving Time (DST): The practice of setting clocks forward one hour in the summer and back one hour in the fall to maximize the amount of sunlight available during daytime hours when the majority of people are awake and active.

Humidification: PAP machine blows air to your airways. This increased airflow will dry your nasal passages. Your body will produce mucous as a reaction to the dryness. This is when you will start getting congested and start breathing by your mouth. The solution is humidification. It will add moisture to the air blown by your CPAP.  The air from the CPAP passes over the warm water in the chamber before it is delivered to your airways. The nasal airways are no longer overwhelmed and nasal congestion is prevented.

Example Total Sleep Time = 8 hours (480 minutes) Minus time to fall asleep = 25 minutes Minus time awake during the night= 30 minutes (5 minutes + 20 minutes +5 minutes) Total time asleep = 7 hours and 5 minutes (425 minutes)

Now divide 425 minutes by 480 minutes = 89% Sleep efficiency above 85% is considered normal; above 90% is considered really good sleep efficiency.

Diabetes: Diabetes is a metabolic disease stemming from elevated blood glucose levels.

Pre-diabetes: Pre-diabetes means that your blood sugar levels are higher than normal, but not high enough for a diabetes diagnosis. People with pre-diabetes have a higher risk of developing type 2 diabetes and cardiovascular disease.

Blood Glucose: Blood Glucose, also known as blood sugar, is the body’s main source of energy. Produced from protein, fat and carbohydrates, blood glucose is used by the body’s cells with the help of insulin to create energy.

Insulin: Secreted by the pancreas, insulin is a hormone that helps the body convert glucose into energy. When the body cannot make enough insulin, it results in diabetes. Insulin can also be taken by injection or from an insulin pump when the body is not creating enough.

Compliance Management Solutions: Compliance Management Solutions are web-based applications that monitor CPAP unit usage and performance. Using your Internet connection, these solutions can then share data via email, voice message or even text (SMS) with your physician or other health care professional. With convenient online access and comprehensive reporting features, Compliance Management Solutions help clients and physicians make data-driven decisions about CPAP treatment plans. Examples of Compliance Management Solutions include EasyCare Online from ResMed, EncoreAnywhere from Philips, and InfoSmart Web from Fisher & Paykel.

Hypoventilation: The result of breathing too shallow (hypopnea) or too slow (bradypnea) to meet the needs of our bodies, hypoventilation (also known as respiratory depression) causes oxygen levels to be too low and carbon dioxide levels to be too high.

SP02 (Saturation of Peripheral Oxygen): SP02 is a measure of how much oxygen-carrying hemoglobin is in the blood. For example, people with compromised breathing may have low oxygen saturation.

BMI: This acronym stands for Body Mass Index. It is commonly used to screen for health risk based on height and weight. High BMI is a strong risk factor associated with OSA.

Compliance: When we refer to compliance, it is in regards to how much you use your CPAP machine with associated accessories. This includes the number of nights you use it (minimum 5 nights per week), and how long you use it for each night (minimum 4 hours). CPAP compliance can also include seeing your physician on a regular basis to ensure that your therapy is working.

Durable Medical Equipment (DME): This term refers to medical equipment used in the home to help provide a better quality of life for someone with a health condition, illness or injury. These medical items are often covered by insurance, and include items such as CPAP machines, walkers, oxygen equipment, nebulizers, hospital beds and wheelchairs.

Sleep latency: The time between “lights out”, also known as “going to bed”, and the actual onset of sleep is called sleep latency.

Cheyne-Stokes Respiration: This abnormal breathing pattern includes progressively faster and deeper breathing, followed by shallower breathing. Then there is a temporary stoppage of breathing (apnea). This pattern can last anywhere from 30 seconds to two minutes.

Calories (nutritionists most commonly used kilocalories): They are a unit of measure expressing heat-producing or energy-producing value in food when oxidized in the body. Calories are essential to give your body energy. But eating too many calories — and not burning enough of them off through activity — can lead to weight gain.