Alaska Sleep Education Center

Understanding Sleep Study Results A Personal Sleep Study Experience II

Posted by Laci Michaud on Dec 18, 2015 9:58:59 AM

Understanding sleep study results isn't easy. 

Last week I discussed my personal sleep study experience outlining what to expect when you have a sleep study.  I discussed my background with sleep troubles, my love of sleep, and a random dream that woke me up during the middle of my study.  If you haven’t read it yet you can read it here.

Sleep Study Results Decoded

I am going to discuss and break down my sleep study results using the least amount of technical medical jargon I possibly can. If you want to follow along you can view a PDF of my complete sleep study results Michaud_Laci-_Final_Sleep_Study_Results.

Sleep Architecture:


The study started at 10:31 pm and ended at 5:16 am.  The totally recorded time was 6.73 hours or 404 minutes.  Total confirmed sleep time was 370.5 minutes out of 404 minutes, which means I slept efficiently for 91.7% of the study.  I fell asleep 9.5 minutes after the lights were turned off and I fell into my REM cycle 1 hour and 22.5 minutes into my sleep.    

I spent the following amounts in each sleep stage/cycle:

3.4% in Stage N1 - This first cycle of sleep is describedSleep stages of this lady's study. as drowsiness. Eyes are closed during Stage 1 sleep. A person can be awakened without much difficulty but may feel as if they haven’t slept at all.

37.9% in Stage N2 – This is a light stage of sleep. Spontaneous periods of muscle tightening mixed with periods of muscle relaxation are reported. The heart rate will slow and body temperature decreases, helping the body to prepare for deep sleep

22.4% in Stage N3 – These are the deep sleep stages. These stages are known as slow-wave or delta sleep.

36.3% in REM cycle - Intense dreaming occurs during the REM cycle. This results from the heightened cerebral activity, but paralysis occurs simultaneously in the major voluntary muscle groups, such as the sub-mental muscles. The first period of REM sleep typically lasts about 10 minutes, with each recurring REM stage lengthening, eventually with the final stage lasting an hour.  Side Note: Most people spend around 20% in REM, and at 36.3% that makes a dreamer!

My wake after sleep onset (WASO) was 24 minutes. This is the amount of time spent awake after sleep has been initiated and before the final awakening.  It is increased in people who have difficulty staying asleep, such as an insomniac. 

The number of arousals and awakenings is registered in the study and reported as a total number and as a frequency per hour of sleep, which is referred to as an index. The higher the arousal index, the more tired you are likely to feel, though people vary in their tolerance of sleep disruptions. As few as five arousals per hour can make some people feel chronically sleepy, and I had 7 per hour, no wonder I feel tired all the time. 

Respiratory Parameters:

Below is a list of all the terminology discussed in the respiratory parameters paragraph:

Apnea: Apnea literally translates as "cessation of breathing" which means that during sleep a person with sleep apnea stops breathing periodically during the night. 
Obstructive:  Obstructive Apnea is caused by blockage of the upper respiratory airways in which the throat muscles collapse, the tongue falls back into the airways.
Mixed: Mixed apneas are classified for categorization and pathophysiology purposes in the same category as obstructive apneas (obstructive apneas and mixed apneas count together as indicators of upper airway obstruction as the underlying pathology).
Central: Central Apnea is where your brain is not sending the message to your body to breathe.  (How scary is that?!?!)
Hypopneas: Hypopneas is a medical term for a disorder that involves episodes of overly shallow breathing or abnormally low respiratory rates.
RERA: Respiratory Event Resulting in Arousal (RERA) that doesn’t include the fore mention criteria above (apnea, hypopnea, etc).
Supine: Supine is the position where the body lying on its back with the face-up.
Apnea-Hypopnea Index (AHI): The AHI is the number of apneas or hypopneas recorded during the study per hour of sleep. It is generally expressed as the number of events per hour. 
Respiratory Disturbance Index (RDI): This can be confusing because the RDI includes not only apneas and hypopneas, but may also include other, more subtle, breathing irregularities. This means a person's RDI can be higher than their AHI.
Oxygen Desaturation: Reductions in blood oxygen levels (desaturation).

If you would like more in-depth information on the different types of sleep disturbances you can view the American Sleep Medicine’s Study Terminology.

The respiratory parameters paragraph is the area where I lose all energy to even try and understand and comprehend what this paragraph means.   So, I sat down with a certified sleep technician to help me better understand this paragraph, my results, and what they mean.


During my sleep study I had a total of nine respiratory disturbances that lasted for 1tenseconds or more:  In total, I had four hypopneas and four RERAs with one obstructive apnea.  Now, I’m not a doctor but given my dream that I had (inset last week’s blog link) where I was being chased and running, from which I awoke dramatically gasping for air (hypopnea) might have something to do with some of the numbers that I received.   Overall my results were pretty normal.

I slept on my back 39% percent of the time.  Wow!  I am truly amazed by that percentage because I go to bed on my side and wake up sleeping on my side; I just assumed I didn’t sleep on my back at all during the night.  Wrong!  To top that off, any sleep disturbance I did have was only because I was lying in the supine position (on my back). 

Leg Movement Data:


I was lucky in the fact that I didn’t have a lot of leg movement, and any leg movement I did have didn’t wake me up.  Most patients are actually not aware of their involuntary limb movements. The limb jerks are more often reported by bed partners. Patients experience frequent awakenings from sleep, non-restorative sleep, daytime fatigue, and/or daytime sleepiness.  More for information see Alaska Sleep Clinic’s Blog on Periodic Limb Movement Disorder.

Cardiac Data:


During a sleep study, you will wear two leads that measure premature ventricular contractions (PVCs) and your heart rate.  A normal EKG has 12 leads, so the overnight study is not as inclusive but allows the sleep technicians and doctor to know what the average heartbeats per minute are during your study.  People who stop breathing during sleep normally see a rise in heart rate.

A normal resting heart rate for adults ranges from 60 to 100 beats per minute (bpm).  Mine was 91 bpm which is a little on the high side, However, considering I spent around 36% of my sleep time in REM (where your heart rate and respiration speed up and become erratic) it makes more sense.  



Here the results of your study are broken down to better understand any issues/irregularities.  From the looks of it, I might have some snoring issues.  And to think, I blamed all my ex-boyfriends for the snoring…turns out, it may have been me (hides face in shame).


I snore.  Haha!  I don’t know why this makes me laugh but it does, how utterly unromantic.



The above photo outlines the recommendations the board-certified sleep doctor suggested for me personally.

Positional Therapy:

Positional therapy is a behavioral strategy to treat those who experience respiratory disturbances and/or apneas while in the supine position. Since I have a side sleeper Tempur-Pedic pillow at home (I didn’t bring it in for the study) I am now on the hunt for something that prevents me from rolling onto my back during sleep.  One possible option is a positional therapy pillow specifically designed for my back or knees. 

Even though the results of my study showed that I have fairly good sleep health, I was still able to discover potential areas of my sleep that could prove problematic down the road.  If you even suspect that your health is being impacted by your sleep you should consider having a sleep study.  The Alaska Sleep Clinic specializes in diagnosing and treating a variety of sleep disorders. If you live in Alaska and are ready to get your sleep disorder under control, sign up for a sleep study today by clicking the link below and take the first step towards more fulfilling sleep.

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