New Delhi | July 30, 2025 :A groundbreaking study involving over 88,000 adults has revealed that your sleep rhythm—not just how long you sleep—could be a powerful predictor of future disease risk. Published on June 3, 2025, in Health Data Science, this large-scale investigation found strong links between objectively measured sleep traits and over 170 diseases, ranging from liver conditions and metabolic disorders to neurological and cardiovascular illnesses.

Unlike earlier studies that relied on self-reported sleep data, this one used wearable devices to track sleep patterns with precision. Researchers say the findings challenge long-held beliefs about sleep duration being the main driver of sleep-related health issues.

The Study at a Glance
The research team analyzed data from 88,461 participants in the UK Biobank who wore wrist accelerometers for up to a week. This allowed for objective measurement of various sleep traits, including bedtime consistency, sleep efficiency, rhythm, and duration.

These sleep metrics were then compared with hospital inpatient records, using a phenome-wide association study (PheWAS) approach. This means the researchers tested sleep traits against a broad spectrum of 363 disease categories using ICD-10 codes. To ensure the validity of their results, they controlled for multiple variables such as age, sex, ethnicity, lifestyle, socioeconomic status, and medication use. They also cross-referenced their findings with published data based on subjective sleep reports.

Key Findings
1. Over 170 Diseases Tied to Sleep Traits
The study uncovered associations between poor sleep patterns and 172 different diseases. More than 40 of these showed a twofold or greater increase in risk. For instance, individuals with low sleep rhythm (measured as relative amplitude) had over three times the risk of age-related physical debility. A late bedtime (after 12:30 am) was linked with more than double the risk of liver cirrhosis and fibrosis compared to those who went to bed between 11:00 and 11:30 pm.

Another surprising connection: low sleep stability significantly increased the risk of gangrene. These are not conditions typically associated with sleep, highlighting how wide-reaching the health impacts of sleep behavior can be.

2. Sleep Rhythm Was More Important Than Duration
Nearly half of the disease associations were linked to sleep rhythm traits like regularity and stability, rather than duration. While sleep duration has long been a focus of sleep hygiene campaigns, this research suggests that consistent sleep-wake patterns may be even more critical.

The researchers found that irregular sleep timing, poor rhythm, and fragmented sleep had stronger and more consistent links to health conditions than just sleeping too much or too little.

3. Self-Reported Sleep Often Misleading
A key comparison in the study was between subjective (self-reported) and objective (device-measured) sleep traits. The researchers found that many previously reported associations—such as long sleep duration being linked with poor health outcomes—were likely misleading.

About 20% of participants who reported sleeping 9 hours or more were actually short sleepers, getting less than 6 hours of actual sleep. This discrepancy led to inflated risk estimates in prior studies that relied on self-reports. When recalculated using objective data, many of these risks disappeared or weakened significantly.

4. Disease Risk Attributable to Sleep
For more than 90 diseases, poor sleep explained over 20% of the risk. For example, nearly 37% of Parkinson’s disease risk and 36% of type 2 diabetes risk were attributable to problematic sleep traits. Even conditions like acute kidney failure and depressive disorders showed significant contributions from irregular or fragmented sleep.

5. Biological Mechanisms Confirmed
To validate their findings, researchers replicated results in a U.S.-based population using NHANES data. They also investigated biological pathways and found that markers of inflammation, including C-reactive protein and white blood cell counts, appeared to mediate the relationship between poor sleep and disease risk. This adds a layer of biological plausibility to the associations.

Why This Matters
This study offers one of the most comprehensive pictures yet of how sleep affects health. It moves beyond the basic “get eight hours” advice and emphasizes the importance of sleep quality, rhythm, and consistency.

Experts say this could reshape how sleep disorders are diagnosed and treated, and even how wearable health tech is used in preventive medicine. Encouraging people to go to bed at a regular time and reduce sleep fragmentation may prove just as important—if not more so—than simply extending sleep time.

Final Thoughts
For years, sleep advice has focused on getting enough hours. This study suggests it’s time to focus on how we sleep. Regular bedtimes, consistent rhythms, and efficient, undisturbed sleep may be the keys to preventing a broad range of health issues—from kidney disease to diabetes to neurodegeneration.

The takeaway? If you want to invest in your long-term health, start by syncing your internal clock—not just hitting snooze.