A recent expert review, published in Sleep Medicines Reviews, advances the viewpoint that this anatomic perspective, while important, captures only part of the picture. The paper brings together evidence from across sleep medicine, cardiology, neuroscience, obesity research, bio-computation, and advanced medical imaging to propose a systems-based, functional view of sleep apnoea, and one that focuses on the underlying physiological mechanisms and long-term outcomes rather than anatomy alone.
The review synthesises a wide body of existing research to explore how complex biological processes interact in sleep apnoea, and how this interaction may help explain its links to heart disease, brain health and obesity.
A two-way relationship with obesity
One of the central themes of the review is the close, two-way relationship between sleep apnoea and obesity. Excess body fat, particularly visceral fat stored deep in the abdomen, increases the likelihood of airway collapse during sleep. At the same time, disrupted sleep alters metabolism, and hormone appetite regulation increasing the risk of weight gain over time. This interplay thus positions sleep apnoea within a broader cardiometabolic context, with implications for health systems globally, given the obesity pandemic.
'Sleep apnoea needs to be understood as part of a wider physiological framework,' said Betty Raman, Wellcome Clinical Career Development Fellow and Associate Professor of Cardiovascular Medicine in the Oxford Centre for Clinical Magnetic Resonance Research, and a co-author of the review.
'Looking at this complex disorder through a systems and functional lens helps explain why it so often coexists with cardiometabolic disease, and why single-factor approaches can fall short.'
Functional effects on the brain and heart
The review highlights growing evidence that sleep apnoea has measurable physiological effects on both the brain and the heart. Repeated drops in oxygen levels during sleep, known as intermittent hypoxia, trigger oxidative stress, inflammation and changes in metabolism.
Advanced brain imaging techniques, such as MRI and PET, show alterations in cerebral blood flow, metabolism and connectivity in people with sleep apnoea. These changes are relevant to cognition and stroke risk, and may persist even when symptoms are subtle.
Similarly, heart imaging studies reveal changes in cardiac structure, function and energy use, particularly affecting the right side of the heart, left heart-wall diastolic function, and the heart's ability to respond to physiological stress. Importantly, these effects can be detected before overt cardiovascular disease develops.
The authors emphasise that such imaging tools are primarily research and risk-stratification tools, rather than routine clinical tests. Their value lies in objectively indexing underlying physiology and monitoring long-term clinical outcomes.
Integrating treatment approaches
Given this complex environment, the review suggests that optimal management of sleep apnoea is likely to reside at the intersection of multiple approaches: cardiometabolic health, behavioural and lifestyle interventions, mechanical therapies such as CPAP, and newer systemic pharmacotherapies.
Recent trials of anti-obesity drugs, including GLP-1–based treatments, suggest that weight-loss-driven improvements in physiology can reduce sleep apnoea severity in selected patients. These therapies are regarded not as replacements for established treatments, but as additional tools within an enhanced, personalised-medicine framework.
Complexity, emergence and future directions
The review also explores theoretical models drawn from complexity science, which view brain The review also explores a novel theoretical model based on complexity science, which views brain function as an emergent property of a vast network of interacting neurons. While speculative, requiring further experimental validation, such a far-reaching model may offer new ways of understanding complex biological phenomena like the sleep-wake cycle, with potential implications for studying the phenomenon of consciousness and other advanced brain functions.
This systems-motivated collaborative review was conceptualized and led by Professor Garth M. Beache, MD, of University of Louisville, School of Medicine, USA, Emeritus Associate Professor of Radiology, and was especially notable for the comprehensive range of expertise, and trans-national collaboration, that included internationally recognised experts, including Mayo Clinic Cardiovascular Medicine specialist and sleep researcher, Professor Virend K. Somers and Professor Betty Raman, Radcliffe Department of Medicine.
Looking ahead, the review calls for closer collaboration across disciplines - an approach where diverse expertise can converge to reveal unsuspected complex phenomenon in health and disease.