Increased adoption of wearable technology is changing this dynamic, allowing researchers to analyze multiple dimensions of sleep health (for example, duration, timing, regularity, and quality, to varying extents), along with wake activities, over extended periods in users\u2019 natural environments.\u00a0<\/p>\n
In fact, wearables are a key focus of a recently renewed collaborative partnership between Monash University and Brigham and Women\u2019s Hospital. The international alliance between Australia\u2019s largest university and one of Boston\u2019s largest hospitals, now in its seventeenth year of sleep and circadian research, aims to leverage mobile health technologies to bridge basic sleep physiology, clinical trials, and public health policy.<\/p>\n
\u201cWearables allowed us to recognize that sleep is not something that happens during night hours and then that\u2019s it,\u201d says Emmanuel Stamatakis, PhD, director of Brain Park at Monash University\u2019s Turner Institute for Brain and Mental Health. Rather, sleep is acknowledged as part of a 24-hour day.\u00a0<\/p>\n
\u201cThe advantage of wearables is they\u2019ve popularized that idea of living whole lifestyles because most trackers capture in great detail all behaviors including posture (eg, standing, sitting), sleep parameters, and physical activity parameters,\u201d Stamatakis says, \u201cand they attempt to somehow wrap them into one package and support lay consumers to improve their behavior.\u201d<\/p>\n
Synergy with Sleep<\/p>\n
Because wearables can estimate sleep duration with reasonable accuracy while simultaneously tracking physical activity, researchers can measure the small day-to-day changes that questionnaires invariably miss, making it possible to study how sleep interacts with other lifestyle behaviors\u2014and how those interactions influence long-term health. \u201cQuestionnaires have a lot more measurement error noise [than objective wearables], so they misclassify behavior and do not allow us to estimate relatively small increments.\u201d\u00a0<\/p>\n
Monash-Brigham researchers are discovering that sleep may have a greater impact on health when considered alongside other daily behaviors rather than in isolation.<\/p>\n
Epidemiological studies consistently show that relatively small improvements across sleep, physical activity, and diet can work together to produce meaningful health benefits. Adding just 5 to 10 minutes of sleep per night, 2 to 4 minutes of moderate-to-vigorous physical activity per day, and about half a cup of fresh vegetables daily is associated with an approximately 10% reduction<\/a> in the risk of major adverse cardiovascular events over seven to eight years.1<\/p>\n The combined effect appears to be greater than the sum of its parts. Achieving a similar reduction in cardiovascular risk through any one behavior alone would require substantially larger changes\u2014for example, roughly 30 additional minutes of sleep per night. \u201cThere seems to be a synergy,\u201d Stamatakis says.\u00a0<\/p>\n That distinction is important because sustained behavior change is notoriously difficult. \u201cIt may sound modest. It\u2019s not modest at all. Health-related behavior is very difficult to change,\u201d Stamatakis says. Identifying the smallest changes that still produce measurable health benefits could make public health interventions more attainable.<\/p>\n This objective measurement also provides a more precise basis for behavior change. While subjective reporting remains valuable for understanding a patient\u2019s experience, wearables provide tangible markers that can be used to coach patients toward improved health habits.<\/p>\n Sleep Regularity Index<\/p>\n Wearables have also helped elevate another dimension of sleep health that until recently received far less attention than duration: sleep regularity.<\/p>\n \u201cOver the past few decades, we have increased our understanding that sleep has multiple dimensions that influence health,\u201d says Shantha M.W. Rajaratnam, PhD, head of the Monash School of Psychological Sciences and co-leader of the Monash-Brigham collaboration. \u201cWhat early work done at the Brigham\u2014and expanded through the collaboration at Monash\u2014showed was that sleep regularity is an independent and important health metric.\u201d<\/p>\n Much of that work was led by Andrew Phillips, PhD, an Australian sleep and circadian researcher who trained at Brigham and Women\u2019s Hospital, later established a faculty position and research program at Monash University, and more recently moved to Flinders University. Phillips and colleagues developed the Sleep Regularity Index (SRI)<\/a> at Brigham and Women\u2019s Hospital, which measures how consistently a person is asleep or awake at the same time on consecutive days.2<\/p>\n Continuous wearable monitoring made the metric possible. In a collaborative, cross-institutional study using more than 10 million hours of accelerometer data from nearly 61,000 UK Biobank participants, Phillips and colleagues showed that sleep regularity was a stronger predictor of all-cause mortality<\/a> than sleep duration alone. Participants with the most regular sleep schedules had substantially lower risks of all-cause, cancer, and cardiometabolic mortality than those with the most irregular sleep schedules, independent of how long they slept.3<\/p>\n The findings have since been reinforced by additional epidemiological studies linking irregular sleep patterns to cardiovascular disease, diabetes, dementia, and other chronic conditions.<\/p>\n \u201cThis comes purely from the capabilities that wearable devices permit,\u201d says Stamatakis. \u201cIt wouldn\u2019t have been possible to develop the Sleep Regularity Index without the UK Biobank and the richness of data that wearable devices provide.\u201d<\/p>\n For Rajaratnam, the work illustrates the value of long-term international collaboration. \u201cThe partnership between Monash and the Brigham really gave rise to a significant program of work around the role of sleep regularity in influencing the risk of a range of diseases\u2014from cardiometabolic to neurocognitive to mood disorders,\u201d he says.<\/p>\n Research Versus Consumer Wearables<\/p>\n Despite the proliferation of wearable devices, a divide remains between research-grade and consumer-grade technology. Research-grade devices, typically triaxial accelerometers, are valued for their transparency and validated algorithms. However, they often lack the multi-sensor capabilities found in modern consumer smartwatches and rings, such as photoplethysmography for heart rate, pulse oximetry, and temperature sensors.<\/p>\n Consumer-grade devices are more technologically advanced and user-friendly, leading to higher long-term usage. The barrier to their use in rigorous academic research is the proprietary nature of their algorithms. \u201cBy not making the data processing algorithms transparent, it is very hard to use them [in scientific research] because the consumer-grade wearables become black boxes,\u201d Stamatakis says.<\/p>\n Some manufacturers have begun to cooperate by making raw, unprocessed data available to researchers, a move Stamatakis describes as highly desirable. Access to raw signals would allow researchers to apply standardized, transparent algorithms to the more advanced sensor suites found in consumer devices, potentially enabling more accurate sleep staging and physiological monitoring at scale.<\/p>\n Also, while wearables have moved beyond actigraphy only, gaps still exist. Distinguishing between quiet rest and actual sleep remains a challenge, as does the detection of short daytime naps. Furthermore, while consumer devices claim to measure sleep stages, the validity of these measurements compared to gold-standard polysomnography is a subject of ongoing validation.\u00a0<\/p>\n Open-science projects like The Wearable Landscape<\/a> and Open Wearables are working to standardize validation and data interpretation processes. Available at wearable-landscape.info\/vision<\/a>, The Wearables Landscape is building a centralized platform and interactive dashboard to pool validation studies and research protocols for 24-hour physical behaviors, including sleep. While at openwearables.io<\/a>, developers launched a platform to unify wearable health data through an artificial intelligence-ready application programming interface.<\/p>\n Global Public Health Implications<\/p>\n The data generated by wearables is expected to influence the next generation of public health recommendations. Current guidelines, such as the Physical Activity Guidelines for Americans<\/a> and World Health Organization guidelines<\/a>, have historically focused on exercise and sedentary behavior.<\/p>\n Future updates are likely to incorporate sleep into a more holistic 24-hour framework, predicts Stamatakis. They will likely include more sophisticated recommendations on sleep regularity and timing, moving beyond the basics of simply getting seven to nine hours.<\/p>\n Rajaratnam envisions wearables playing a key role in the implementation of these policies. \u201cA wearable is able to quantify multiple dimensions of sleep health, as well as getting to what a person\u2019s current sleep debt is, which is reflective of the night before but also of her recent sleep history over several days or weeks,\u201d he says. \u201cThat\u2019s why I think these wearables offer us a really significant opportunity in public health policy implementation.\u201d<\/p>\n The collaboration driving much of this work continues to expand. Co-leader of the Monash-Brigham collaboration Charles Czeisler, MD, PhD, chief of the division of sleep and circadian medicine in the Department of Medicine at Mass General Brigham, says the partnership has evolved from a small faculty exchange into a jointly funded international research program supported by a five-year Wellcome Trust grant. \u201cIt\u2019s been exciting to see how the initiative has grown from just a few scholars in the exchange to now a steady drumbeat,\u201d he says.<\/p>\n The work is also becoming more global. Most wearable-derived sleep evidence comes from high-income countries, even though most of the world\u2019s population lives in low- and middle-income countries. Differences in climate, culture, work schedules, and socioeconomic conditions may all influence how sleep affects health, making it important to expand research beyond Western populations.\u00a0<\/p>\n
![\"Trish](\"https:\/\/www.newsbeep.com\/au\/wp-content\/uploads\/2026\/08\/Monash-Turner-clinics-Notting-Hill-Sleep-clini-2500x1530.jpg\")
Trish Emperado, PGDipMedTech, Monash University\u2019s Edwards Lab manager and project coordinator and Brad Edwards, PhD, director of the Sleep & Circadian Rhythm Research Program and Head of Sleep Disorders Research Laboratory at Monash University, attach electrodes to the scalp of Georgina Rawson, a PhD Candidate in the Edwards Lab.<\/p>\n