Table of ContentsView AllTable of ContentsWhat Is the ODI?Scoring GuidelinesWhat Causes Worsened ODI?Health ConsequencesTreatment
Table of ContentsView All
View All
Table of Contents
What Is the ODI?
Scoring Guidelines
What Causes Worsened ODI?
Health Consequences
Treatment
The oxygen desaturation index (ODI) is a measure of insufficient blood oxygen (low levels) during sleep. If you have a diagnosticsleep study, this measure can be one of the components in the report that you receive describing your results.
The ODI scores may be one part of a pattern of symptoms and findings that suggest obstructivesleepapnea(OSA), or certain heart and lung conditions, are a cause of low oxygen levels. Other factors that contribute to OSA risk include age over 50, abody mass indexconsidered overweight or obese, and certain facial features associated with a more narrow upper airway.
Grace Cary / Getty Images
Desaturations can occur due to illnesses (like lung disease) while you are awake, but they are even more likely to occur while you are asleep.Sleep apneais the most common cause of oxygen desaturation during sleep.
The ODI is typically measured as part of standard sleep studies, such as:
Pulse Oximeter and ODI
Breathing and Oxygen Levels
Several other aspects of your breathing can affect your oxygen saturation and your ODI results, and they are each separately reported as part of a comprehensive sleep study. These factors include:
While it can cause low oxygen levels at night, sleep apnea does not cause low oxygen levels during the day. Still, your low daytime levels may lower if you have a sleep-related disorder. One study of people with COPD found that those with low daytime oxygen levels were more likely to have problems breathing while sleeping. Whether low daytime oxygen can predict desaturation at night is still being studied, however.
Although a normal oxygen desaturation index level has not been universally established, the most common level to be considered normal is fewer than five desaturation episodes per hour of sleep.
Normal oxygen saturation when you’re sleeping or awake should be 96% to 97%. A drop below 90% is considered mildly abnormal, while 80% to 89% is considered moderately abnormal. A drop below 80% is considered severely abnormal.
A dangerously low oxygen level at night or during the day is anything below 88% and requires immediate medical attention.
Generally, your oxygen levels will drop slightly during sleep. This is because your respiratory rate and volume tend to be reduced when you’re sleeping.
Your ODI score is based on how much and how often your oxygen level drops during the test. The degree of change from baseline can be measured in two different ways with the following criteria:
How low oxygen drops with sleep apnea varies depending on other factors. For example, anemia, hypotension, peripheral vascular disorders, obesity, COPD, and frequent movement during sleep can all affect the score when a pulse oximeter is used.
Generally, longer and deeper desaturations are associated with worse obstructive sleep apnea (OSA), and scoring criteria are designed to reflect these components.
AHI (Apnea-Hypopnea Index): Understanding Your Results
What Causes Worsened ODI?
During sleep, muscle tone diminishes a little. This doesn’t have a noticeable or substantial effect on most people.
However, the normal decline in muscle tone during sleep means that illnesses that affect breathing or blood oxygen can make low oxygen levels (and ODI) worse.
Apnea and Hypopnea
When breathing becomes disrupted during sleep, the oxygen levels of the blood can fall repeatedly. With OSA and other conditions that affect ODI, these drops are typically associated with apnea or hypopnea.
The ODI differs from theapnea-hypopnea index (AHI), which is another measurement. The AHI also includes events that may cause arousal or awakenings from sleep without affecting oxygen levels.
Sleep FragmentationSleep fragmentation (an interruption of sleep) can occur due to breathing issues. It can happen with or without the associated desaturations. Even when sleep fragmentation occurs without an effect on oxygen saturation, it can cause daytime sleepiness.
Sleep Fragmentation
Sleep fragmentation (an interruption of sleep) can occur due to breathing issues. It can happen with or without the associated desaturations. Even when sleep fragmentation occurs without an effect on oxygen saturation, it can cause daytime sleepiness.
Other Causes
Other conditions can cause problems with breathing and/or oxygenation during sleep and affect your ODI.
For example:
Several of these conditions contribute to each other, and OSA often coexists with other medical issues that affect breathing, such as COPD. With diminished lung capacity and/or heart function, the collapse of the upper airway may cause your blood’s oxygen levels to drop more quickly and to a larger degree than they would if you had only OSA.
Recurrent episodes of oxygen desaturation can lead tohypoxemia(diminished blood oxygen) andhypoxia(diminished oxygen in the body tissues).
Hypoxia and hypoxemia can be harmful to your body, especially if the problem is prolonged and recurrent. ODI may also be associated with:
These factors may contribute to the risk of long-term health problems, including:
Cancer, heart arrhythmias likeatrial fibrillation, and memory loss associated withdementiaalso are active areas of sleep research.
The treatment for ODI abnormalities during sleep depends on the cause. Generally, OSA, the most common cause of ODI problems, is treated withcontinuous positive airway pressure (CPAP).It can normalize breathing and reduce the long-term risks associated with untreated sleep apnea.
Sometimesother sleep apnea treatments, including surgery, are considered as a treatment for OSA that doesn’t improve with more conservative measures.
Lifestyle changes that can help include:
Sometimes treatment of lung disease or heart disease can help improve ODI.For some people who have OSA or other causes of ODI problems,home oxygen supplementationcan be helpful.
Summary
The oxygen desaturation index (ODI) measures your oxygen levels while you are sleeping and is an important tool for diagnosing and managing obstructive sleep apnea. Your ODI score is an assessment of how much and how often your oxygen level drops during the test.
The scores may be interpreted differently, and they are used alongside other factors that contribute to sleep apnea, or heart and lung diseases that can cause breathing disruptions while you sleep.
If you think you may be experiencing sleep disruptions, talk to your healthcare provider about whether a sleep study would be useful in diagnosing your condition and exploring treatment options. Resolving sleep-disordered breathing may benefit both sleep quality and long-term health.
14 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Mitra AK, Bhuiyan AR, Jones EA.Association and Risk Factors for Obstructive Sleep Apnea and Cardiovascular Diseases: A Systematic Review.Diseases. 2021 Dec 2;9(4):88. doi:10.3390/diseases9040088.U.S. Centers for Medicare & Medicaid Services.CPAP for obstructive sleep apnea.Kryger MH, Roth T, Dement WC.Principles and Practice of Sleep Medicine, 6th edition. Elsevier.Silva JLR, Conde MB, de Sousa Corrêa K, Rabahi H, Rocha AA, Rabahi MF.Sleep-disordered breathing in patients with COPD and mild hypoxemia: prevalence and predictive variables.J Bras Pneumol. 2017;43(3):176-182. doi:10.1590/S1806-37562016000000051Temirbekov D, Güneş S, Yazıcı ZM, Sayın İ.The ignored parameter in the diagnosis of obstructive sleep apnea syndrome: the oxygen desaturation index.Turk Arch Otorhinolaryngol. 2018;56(1):1-6. doi:10.5152/tao.2018.3025Pellegrino GM, Corbo M, Di Marco F, et al.Effects of air stacking on dyspnea and lung function in neuromuscular diseases.Arch Phys Med Rehabil.2021 Mar 9:S0003-9993(21)00185-4. doi:10.1016/j.apmr.2021.01.092MedlinePlus.Pulse oximetry.Kapur VK, Donovan LM.Why a Single Index to Measure Sleep Apnea Is Not Enough.J Clin Sleep Med. 2019 May 15;15(5):683-684. doi:10.5664/jcsm.7746.Karhu T, Myllymaa S, Nikkonen S, Mazzotti DR, Töyräs J, Leppänen T.Longer and deeper desaturations are associated with the worsening of mild sleep apnea: The Sleep Heart Health Study.Front Neurosci.2021 Apr 28;15:657126. doi:10.3389/fnins.2021.657126Rashid NH, Zaghi S, Scapuccin M, Camacho M, Certal V, Capasso R.The value of oxygen desaturation index for diagnosing obstructive sleep apnea: A systematic review.Laryngoscope.2021 Feb;131(2):440-447. doi:10.1002/lary.28663Gerçek M, Oldenburg O, Gerçek M, et al.Prevalence of sleep disordered breathing in patients with primary mitral regurgitation undergoing mitral valve surgery.J Clin Med.2021 May 10;10(9):2039. doi:10.3390/jcm10092039Lavie L.Oxidative stress in obstructive sleep apnea and intermittent hypoxia–revisited–the bad ugly and good: implications to the heart and brain.Sleep Med Rev. 2015 Apr;20:27-45. doi:10.1016/j.smrv.2014.07.003.Haba-Rubio J, Ouanes S, Franc Y, Marques-Vidal P, Waeber G, Vollenweider P,et al.Do diurnal cortisol levels mediate the association between sleep disturbances and cognitive impairment?Neurobiol Aging. 2018 Sep;69:65-67. doi:10.1016/j.neurobiolaging.2018.05.001.Nokes B, Cooper J, Cao M.Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology.Expert Rev Respir Med. 2022 Aug;16(8):917-929. doi:10.1080/17476348.2022.2112669.
14 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Mitra AK, Bhuiyan AR, Jones EA.Association and Risk Factors for Obstructive Sleep Apnea and Cardiovascular Diseases: A Systematic Review.Diseases. 2021 Dec 2;9(4):88. doi:10.3390/diseases9040088.U.S. Centers for Medicare & Medicaid Services.CPAP for obstructive sleep apnea.Kryger MH, Roth T, Dement WC.Principles and Practice of Sleep Medicine, 6th edition. Elsevier.Silva JLR, Conde MB, de Sousa Corrêa K, Rabahi H, Rocha AA, Rabahi MF.Sleep-disordered breathing in patients with COPD and mild hypoxemia: prevalence and predictive variables.J Bras Pneumol. 2017;43(3):176-182. doi:10.1590/S1806-37562016000000051Temirbekov D, Güneş S, Yazıcı ZM, Sayın İ.The ignored parameter in the diagnosis of obstructive sleep apnea syndrome: the oxygen desaturation index.Turk Arch Otorhinolaryngol. 2018;56(1):1-6. doi:10.5152/tao.2018.3025Pellegrino GM, Corbo M, Di Marco F, et al.Effects of air stacking on dyspnea and lung function in neuromuscular diseases.Arch Phys Med Rehabil.2021 Mar 9:S0003-9993(21)00185-4. doi:10.1016/j.apmr.2021.01.092MedlinePlus.Pulse oximetry.Kapur VK, Donovan LM.Why a Single Index to Measure Sleep Apnea Is Not Enough.J Clin Sleep Med. 2019 May 15;15(5):683-684. doi:10.5664/jcsm.7746.Karhu T, Myllymaa S, Nikkonen S, Mazzotti DR, Töyräs J, Leppänen T.Longer and deeper desaturations are associated with the worsening of mild sleep apnea: The Sleep Heart Health Study.Front Neurosci.2021 Apr 28;15:657126. doi:10.3389/fnins.2021.657126Rashid NH, Zaghi S, Scapuccin M, Camacho M, Certal V, Capasso R.The value of oxygen desaturation index for diagnosing obstructive sleep apnea: A systematic review.Laryngoscope.2021 Feb;131(2):440-447. doi:10.1002/lary.28663Gerçek M, Oldenburg O, Gerçek M, et al.Prevalence of sleep disordered breathing in patients with primary mitral regurgitation undergoing mitral valve surgery.J Clin Med.2021 May 10;10(9):2039. doi:10.3390/jcm10092039Lavie L.Oxidative stress in obstructive sleep apnea and intermittent hypoxia–revisited–the bad ugly and good: implications to the heart and brain.Sleep Med Rev. 2015 Apr;20:27-45. doi:10.1016/j.smrv.2014.07.003.Haba-Rubio J, Ouanes S, Franc Y, Marques-Vidal P, Waeber G, Vollenweider P,et al.Do diurnal cortisol levels mediate the association between sleep disturbances and cognitive impairment?Neurobiol Aging. 2018 Sep;69:65-67. doi:10.1016/j.neurobiolaging.2018.05.001.Nokes B, Cooper J, Cao M.Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology.Expert Rev Respir Med. 2022 Aug;16(8):917-929. doi:10.1080/17476348.2022.2112669.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Mitra AK, Bhuiyan AR, Jones EA.Association and Risk Factors for Obstructive Sleep Apnea and Cardiovascular Diseases: A Systematic Review.Diseases. 2021 Dec 2;9(4):88. doi:10.3390/diseases9040088.U.S. Centers for Medicare & Medicaid Services.CPAP for obstructive sleep apnea.Kryger MH, Roth T, Dement WC.Principles and Practice of Sleep Medicine, 6th edition. Elsevier.Silva JLR, Conde MB, de Sousa Corrêa K, Rabahi H, Rocha AA, Rabahi MF.Sleep-disordered breathing in patients with COPD and mild hypoxemia: prevalence and predictive variables.J Bras Pneumol. 2017;43(3):176-182. doi:10.1590/S1806-37562016000000051Temirbekov D, Güneş S, Yazıcı ZM, Sayın İ.The ignored parameter in the diagnosis of obstructive sleep apnea syndrome: the oxygen desaturation index.Turk Arch Otorhinolaryngol. 2018;56(1):1-6. doi:10.5152/tao.2018.3025Pellegrino GM, Corbo M, Di Marco F, et al.Effects of air stacking on dyspnea and lung function in neuromuscular diseases.Arch Phys Med Rehabil.2021 Mar 9:S0003-9993(21)00185-4. doi:10.1016/j.apmr.2021.01.092MedlinePlus.Pulse oximetry.Kapur VK, Donovan LM.Why a Single Index to Measure Sleep Apnea Is Not Enough.J Clin Sleep Med. 2019 May 15;15(5):683-684. doi:10.5664/jcsm.7746.Karhu T, Myllymaa S, Nikkonen S, Mazzotti DR, Töyräs J, Leppänen T.Longer and deeper desaturations are associated with the worsening of mild sleep apnea: The Sleep Heart Health Study.Front Neurosci.2021 Apr 28;15:657126. doi:10.3389/fnins.2021.657126Rashid NH, Zaghi S, Scapuccin M, Camacho M, Certal V, Capasso R.The value of oxygen desaturation index for diagnosing obstructive sleep apnea: A systematic review.Laryngoscope.2021 Feb;131(2):440-447. doi:10.1002/lary.28663Gerçek M, Oldenburg O, Gerçek M, et al.Prevalence of sleep disordered breathing in patients with primary mitral regurgitation undergoing mitral valve surgery.J Clin Med.2021 May 10;10(9):2039. doi:10.3390/jcm10092039Lavie L.Oxidative stress in obstructive sleep apnea and intermittent hypoxia–revisited–the bad ugly and good: implications to the heart and brain.Sleep Med Rev. 2015 Apr;20:27-45. doi:10.1016/j.smrv.2014.07.003.Haba-Rubio J, Ouanes S, Franc Y, Marques-Vidal P, Waeber G, Vollenweider P,et al.Do diurnal cortisol levels mediate the association between sleep disturbances and cognitive impairment?Neurobiol Aging. 2018 Sep;69:65-67. doi:10.1016/j.neurobiolaging.2018.05.001.Nokes B, Cooper J, Cao M.Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology.Expert Rev Respir Med. 2022 Aug;16(8):917-929. doi:10.1080/17476348.2022.2112669.
Mitra AK, Bhuiyan AR, Jones EA.Association and Risk Factors for Obstructive Sleep Apnea and Cardiovascular Diseases: A Systematic Review.Diseases. 2021 Dec 2;9(4):88. doi:10.3390/diseases9040088.
U.S. Centers for Medicare & Medicaid Services.CPAP for obstructive sleep apnea.
Kryger MH, Roth T, Dement WC.Principles and Practice of Sleep Medicine, 6th edition. Elsevier.
Silva JLR, Conde MB, de Sousa Corrêa K, Rabahi H, Rocha AA, Rabahi MF.Sleep-disordered breathing in patients with COPD and mild hypoxemia: prevalence and predictive variables.J Bras Pneumol. 2017;43(3):176-182. doi:10.1590/S1806-37562016000000051
Temirbekov D, Güneş S, Yazıcı ZM, Sayın İ.The ignored parameter in the diagnosis of obstructive sleep apnea syndrome: the oxygen desaturation index.Turk Arch Otorhinolaryngol. 2018;56(1):1-6. doi:10.5152/tao.2018.3025
Pellegrino GM, Corbo M, Di Marco F, et al.Effects of air stacking on dyspnea and lung function in neuromuscular diseases.Arch Phys Med Rehabil.2021 Mar 9:S0003-9993(21)00185-4. doi:10.1016/j.apmr.2021.01.092
MedlinePlus.Pulse oximetry.
Kapur VK, Donovan LM.Why a Single Index to Measure Sleep Apnea Is Not Enough.J Clin Sleep Med. 2019 May 15;15(5):683-684. doi:10.5664/jcsm.7746.
Karhu T, Myllymaa S, Nikkonen S, Mazzotti DR, Töyräs J, Leppänen T.Longer and deeper desaturations are associated with the worsening of mild sleep apnea: The Sleep Heart Health Study.Front Neurosci.2021 Apr 28;15:657126. doi:10.3389/fnins.2021.657126
Rashid NH, Zaghi S, Scapuccin M, Camacho M, Certal V, Capasso R.The value of oxygen desaturation index for diagnosing obstructive sleep apnea: A systematic review.Laryngoscope.2021 Feb;131(2):440-447. doi:10.1002/lary.28663
Gerçek M, Oldenburg O, Gerçek M, et al.Prevalence of sleep disordered breathing in patients with primary mitral regurgitation undergoing mitral valve surgery.J Clin Med.2021 May 10;10(9):2039. doi:10.3390/jcm10092039
Lavie L.Oxidative stress in obstructive sleep apnea and intermittent hypoxia–revisited–the bad ugly and good: implications to the heart and brain.Sleep Med Rev. 2015 Apr;20:27-45. doi:10.1016/j.smrv.2014.07.003.
Haba-Rubio J, Ouanes S, Franc Y, Marques-Vidal P, Waeber G, Vollenweider P,et al.Do diurnal cortisol levels mediate the association between sleep disturbances and cognitive impairment?Neurobiol Aging. 2018 Sep;69:65-67. doi:10.1016/j.neurobiolaging.2018.05.001.
Nokes B, Cooper J, Cao M.Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology.Expert Rev Respir Med. 2022 Aug;16(8):917-929. doi:10.1080/17476348.2022.2112669.
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