Posted on April 8, 2026
Getty Images
People whose sleep apnoea changes dramatically from night to night are 30 per cent more likely to have a heart attack, stroke or heart failure, reveals a new study from Flinders University
The research, published in the journal SLEEP, shows that it is not just how severe sleep apnoea is that matters, but how much it fluctuates, with wide night‑to‑night swings in breathing problems during sleep linked to a higher risk of serious heart disease
Obstructive sleep apnoea causes repeated pauses in breathing during sleep and affects millions of people worldwide. It is commonly associated with loud snoring, restless sleep and daytime fatigue, but it is also closely linked to heart disease and stroke
Most people tested for sleep apnoea only have their breathing measured on one night and this single snapshot may not be representative in people whose condition varies substantially night-to-night
The study analysed sleep data from more than 3,000 adults who tracked their breathing at home using an under‑mattress sensor. Their sleep patterns were measured over several months and compared with reported heart and stroke conditions
Lead author and sleep expert, Dr Bastien Lechat, from FHMRI Sleep Health says people whose sleep apnoea severity varies from night to night were about one third more likely to have experienced a heart attack, stroke or heart failure, even after accounting for average sleep apnoea severity
“Many people assume sleep apnoea is stable, but the reality is very different, and some nights can be much worse than others, and this repeated up and down strain may place extra stress on the heart,” says Dr Lechat
“A single night sleep test may falsely reassure some patients, because people with mild average sleep apnoea can still be at higher risk if their breathing problems swing dramatically between nights.”
Matthew Flinders Professor Danny Eckert, Director of FHMRI Sleep Health and senior author on the paper, says the findings help explain why heart risk can be difficult to predict in people with sleep apnoea
“The body may struggle to adapt to repeated changes in oxygen levels and sleep disruption. These night‑to‑night swings can quietly stress the heart and blood vessels over time without being picked up by standard testing,” says Professor Eckert
The findings are reinforced by a second large international Flinders led study, published in npj Digital Medicine, which tracked nearly 30,000 people over several years using home based digital health devices
This study found that more severe sleep apnoea, high night to night variability, and even habitual snoring were all linked to faster ageing of the blood vessels, an early warning sign for cardiovascular disease
Importantly, the study led by Dr Lucia Pinilla, found that people with mild sleep apnoea but high nightly variability had blood vessel health similar to those with severe sleep apnoea, highlighting a hidden group at risk
Dr Pinilla says the two studies together show why repeated sleep monitoring is so important
“These findings show that one night tests can miss people at real risk,” says Dr Pinilla. “Sleep should be seen as a moving picture rather than a single photograph, and understanding nightly patterns can help doctors better identify who needs early intervention,” she says
Heart disease remains the leading cause of death globally, and many risk factors are preventable. The researchers say better sleep assessment could become an important tool for identifying cardiovascular risk earlier and tailoring treatment more effectively
The studies also highlight the growing role of home based health technology, which allows sleep and heart health to be monitored over long periods in real world settings
Professor Eckert says multi-night monitoring mirrors how other chronic conditions are managed. “Blood pressure and blood sugar are measured repeatedly over time, and sleep health should be treated the same way,” he says
The researchers stress the studies do not prove that sleep apnoea variability directly causes heart disease. However, they say the strong and consistent associations show the need for longer term studies and changes to how sleep apnoea is assessed
“If you snore or feel unrefreshed after sleep, speaking with a health professional could help uncover hidden risks to your heart and there are many options available for treatment,” says Dr Lechat
The paper, ‘High night-to-night variability in OSA severity is associated with prevalent cardiovascular disease’, by Bastien Lechat, Lucia Pinilla, Kelly Sansom, Andrew Vakulin, Pierre Escourrou (Centre Interdisciplinaire du Sommeil), Jean-Louis Pepin (The Université Grenoble Alpes), Sebastien Bailly (The Université Grenoble Alpes), Sebastien Baillieul (The Université Grenoble Alpes), Amy C. Reynolds, Hannah Scott, Jack Manners, Peter Catcheside, Robert J. Adams and Danny J Eckert was published in SLEEP journal. DOI: 10.1093/sleep/zsag084
See also, ‘Multi night digital assessment of sleep disordered breathing is associated with accelerated vascular aging’, Lucía Pinilla, Kelly Sansom (Murdoch University), Philomène Letzelter, Andrew Vakulin, Ashley Montero, Anna Hudson, Pierre Escourrou, Jean-Louis Pepin, Robert Adams, Peter Catcheside, Bastien Lechat and Danny J. Eckert was published on npj Digital Medicine. DOI: 10.1038/s41746-026-02469-w
Acknowledgements:
DJE is supported by a National Health and Medical Research Council (NHMRC) of Australia Leadership Fellowship (1196261). BL is supported by a NHMRC of Australia Emerging Leadership Fellowship (2025886). JLP and SB are partly supported by the French National Research Agency in the framework of the “Investissements d’avenir” program (ANR-15-IDEX-02) and the “e-health and integrated care and trajectories medicine and MIAI artificial intelligence” Chairs of excellence from the Grenoble Alpes University Foundation; MIAI @ Grenoble Alpes, (ANR-19-P3IA-0003) and STRATA project (ANR-24-CE36-3468-01).
Posted in
College of Medicine and Public HealthFHMRI Sleep Health
