Why your data can look different from night to night
Different scores on different nights are normal. Sleep breathing changes from night to night, so one night should not be treated as the whole story.
One night is not the whole story
Research shows that breathing disturbances during sleep, including drops in blood oxygen levels and the number of apnoea events measured by the apnea-hypopnea index (AHI), can change from one night to another1.
This means that the results from a single night’s sleep test may not accurately reflect your usual sleep pattern, potentially misjudging the severity of your sleep apnoea1,2.
Why does this happen?
Your sleep quality is never the same two nights in a row.
Several factors can influence your results, including:
- sleep position (on your back or side)3
- sleep stages (REM and non-REM sleep)4
- nasal congestion5
- alcohol consumption6
- stress7
All of these can affect your oxygen drop pattern.
Why can a therapy night sometimes look worse?
This is one of the most important things for users to understand.
Some nights may show more oxygen drops even with your mandibular advancement device (MAD). This does not necessarily mean the therapy is less effective. It could simply be linked to more REM sleep4, back sleeping3, nasal congestion8, or other aggravating factors during that specific night.
Because night-to-night variability is real1,2, therapy nights can occasionally have more oxygen drops even when the overall trend with therapy is still positive3,4.
How to read the data more usefully
Focus on patterns across several nights.
A week or two of data is usually more informative than one outlier.
Ask:
- Are nights with the treatment usually steadier than nights without it?
- Do higher-drop nights cluster around the same triggers?
If scores are consistently worse with therapy, or you feel that symptoms are worsening, you can speak with your dentist or sleep clinician.
What to remember
One odd night is a clue, not a conclusion. Trends over time are more trustworthy than single-night blips.
References
- Martinot JB, Le-Dong NN, Tamisier R, Bailly S, Pépin JL. Determinants of apnea-hypopnea index variability during home sleep testing. Sleep Med. 2023;111:86-93. doi:10.1016/j.sleep.2023.09.002
- Fietze I, Dingli K, Diefenbach K, et al. Night-to-night variation of the oxygen desaturation index in sleep apnoea syndrome. Eur Respir J. 2004;24(6):987-993. doi:10.1183/09031936.04.00100203
- Landry SA, Beatty C, Thomson LDJ, et al. A review of supine position related obstructive sleep apnea: Classification, epidemiology, pathogenesis and treatment. Sleep Med Rev. 2023;72:101847. doi:10.1016/j.smrv.2023.101847
- Bonsignore MR, Mazzuca E, Baiamonte P, Bouckaert B, Verbeke W, Pevernagie DA. REM sleep obstructive sleep apnoea. Eur Respir Rev. 2024;33(171). doi:10.1183/16000617.0166-2023
- Alotaibi S, Bin Saddiq BW, Alfarhoud RS, et al. Clinical Effectiveness of Nasal Dilators in Sleep-Disordered Breathing: A Systematic Review and Meta-Analysis. Cureus. 18(1):e100663. doi:10.7759/cureus.100663
- Kolla BP, Foroughi M, Saeidifard F, Chakravorty S, Wang Z, Mansukhani MP. The impact of alcohol on breathing parameters during sleep: A systematic review and meta-analysis. Sleep Med Rev. 2018;42:59-67. doi:10.1016/j.smrv.2018.05.007
- Shyamsukha B, Nimonkar SV, Belkhode VM, Paul P, Godbole S. Assessment of emotional stress among patients suffering from obstructive sleep apnea: A cross-sectional study. J Fam Med Prim Care. 2023;12(7):1389-1393. doi:10.4103/jfmpc.jfmpc_2310_22
- Lan MC, Lan MY, Kuan EC, Huang YC, Huang TT, Hsu YB. Nasal Obstruction as a Potential Factor Contributing to Hypoxemia in Obstructive Sleep Apnea. Nat Sci Sleep. 2021;13:55-62. doi:10.2147/NSS.S288618
This article contains general information about medical conditions and potential treatments. It is not medical advice. If you have any medical questions, please consult your doctor.