A claim you hear on longevity podcasts
Conflicting. Of 4 studies that test it, 2 agree, 1 partly agrees and 1 disagrees.
The claim checked: Sleep-wake regularity predicts death and disease better than how long you sleep Hear it at 58:21
Four studies test this. Two agree, among them the UK Biobank study the episode cites, which found regularity a stronger predictor of death from any cause than duration. A US study found the same pattern. One disagrees: in 9,641 Korean adults, irregular sleep raised the risk only slightly, and not by a clear margin. One partly agrees: steady daily rhythm still predicted death after accounting for sleep. These studies follow people over time, so they show a link. Some measured regularity with a wrist tracker and one by asking people.
Computed from 4 studies that test this point, each judged by two readers, in full. Sources land on both sides. 10 more studies are waiting for a full read and do not count yet.
“machine but basically what he and his colleagues published in January of 2024 is they saw that sleepwake regularity or consistency was a greater predictor of all cause mortality than sleep duration.”
On tape: Daniel Windred and colleagues, published January 2024, UK Biobank, with 'I think it was like' 79,000 people, found sleep-wake regularity a greater predictor of death from any cause than sleep duration. The finding matches the study. The size does not: the paper reports 60,977 people. The published-in-2024 date, the data set and the comparison all match. Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study. Sleep, 2024. Prospective cohort of UK Biobank participants who wore accelerometers for 1 week, with mortality followed for up to 7.8 years; Cox models comparing Sleep Regularity Index and sleep duration, 60,977 UK Biobank participants, mean age 62.8, 55.0% female.
What it found
“Notably, sleep regularity was a stronger predictor of all-cause mortality than sleep duration.”
How the authors extend it
“Using objective measures of sleep in a cohort of > 60 000 individuals, we found that people with less regular sleep patterns have a higher risk of premature mortality, and that sleep regularity is a stronger predictor of mortality risk than sleep duration.”
Authors AJKP and SWC report research funding from Delos and Versalux and co-direct Circadian Health Innovations; SWC also reports funding from Beacon Lighting and consulting for Dyson. No study funder statement appears in the text read. Two readers agreed on the label, and the paper was read in full.
other primary study · 2024 · landmark · cited on tape
“Notably, sleep regularity was a stronger predictor of all-cause mortality than sleep duration.”
Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study. Sleep
Who: 60,997 UK Biobank participants with valid accelerometer sleep data, mean age 62.8, 55.0% female, 97.2% white
PMID 37738616
other primary study · 2026
“When expressed per 1-SD difference, lower SRI and greater variability in sleep midpoint and sleep onset were associated with higher mortality hazards, whereas mean sleep duration was not linearly associated with either outcome ( Supplementary Table S11 ).”
Night-to-night sleep variability and all-cause and cardiovascular mortality: a prospective cohort study with a complementary in vitro circadian-disruption experiment. Front Med (Lausanne)
Who: US adults aged 20 years or older in NHANES 2011-2014 with at least 4 valid accelerometer days
PMID 42871050
other primary study · 2024
“Results showed that lower interdaily stability remains associated with all-cause mortality even after adjustments for sleep or inactivity.”
Is rest-activity rhythm prospectively associated with all-cause mortality in older people regardless of sleep and physical activity level? The 'Como Vai?' Cohort study. PLoS One
Who: Population-based cohort of adults aged 60 or older in Pelotas, Brazil (COMO VAI? study) with valid wrist accelerometry; 62.2% women
PMID 38363743
other primary study · 2025
“Similarly, those with irregular sleep also exhibited a modest but non-significant increase in mortality risk compared with their regular counterparts (adjusted HR, 1.10; 95% CI, 0.96–1.27; p = 0.164).”
The impact of sleep health on cardiovascular and all-cause mortality in the general population. Sci Rep
Who: 9,641 Korean community adults aged 40-69, mean 52.11, 47.4% men, without prior myocardial infarction or stroke
PMID 40819005
One of nine studies agrees: in older US adults, heart and metabolic risk tracked regularity more than duration or timing. Eight partly agree. Irregular sleep was often tied to diabetes, heart disease or dementia even after accounting for sleep length, but most did not compare the two head to head. The later paper named on the episode is a preprint, not yet checked by outside reviewers, so it does not count here.
Computed from 9 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
trial or observed group · 2018 · landmark
“In general, however, associations between cardiometabolic risk and sleep duration/timing were less robust than associations with sleep regularity.”
Validation of the Sleep Regularity Index in Older Adults and Associations with Cardiometabolic Risk. Sci Rep
Who: Racially diverse older US adults from the MESA Sleep Ancillary Study; mean age 68.7 (range 54-93), 54% female
PMID 30242174
other primary study · 2020 · landmark
“Our findings showing increased CVD incidence with variable sleep duration or timing persisted after adjusting for average sleep duration.”
Sleep Irregularity and Risk of Cardiovascular Events: The Multi-Ethnic Study of Atherosclerosis. J Am Coll Cardiol
Who: 1,992 US Multi-Ethnic Study of Atherosclerosis participants free of cardiovascular disease, mean age about 69, who completed 7-day actigraphy
PMID 32138974
other primary study · 2024 · landmark
“Notably, there were more associations for sleep irregularity than any other sleep pattern included in our study.”
Sleep patterns and risk of chronic disease as measured by long-term monitoring with commercial wearable devices in the All of Us Research Program. Nat Med
Who: US All of Us adults with Fitbit data of at least 6 months linked to health records; median age 50.2 years, 71% female, 84% white, 71% college educated
PMID 39030265
other primary study · 2025
“MACE showed a similar trend, with a higher unadjusted incidence in the > 8 h group; however, none of the sleep duration, regularity, and sufficiency variables were significantly associated with MACE after adjustment (Supplementary Table 2).”
The impact of sleep health on cardiovascular and all-cause mortality in the general population. Sci Rep
Who: Korean adults aged 40-69 in the Ansung-Ansan cohort without baseline myocardial infarction or stroke, mean age 52.11, 47.4% men
PMID 40819005
other primary study · 2026
“This study highlights the association between sleep regularity and T2D risk, revealing that irregular sleep patterns –measured by five indicators – are significantly associated with the risk of T2D.”
Objectively measured sleep regularity, weekend recovery sleep, and the risk of incident type 2 diabetes: a prospective cohort study from the UK Biobank. Int J Surg
Who: UK Biobank participants with 7 days of accelerometer data and no prevalent diabetes; median age about 60 to 65 years by group, mostly White
PMID 41263398
other primary study · 2025
“Using individuals with regular sleep and adequate sleep duration as the reference group (HR = 1.00), those with moderately irregular and irregular sleep patterns exhibited elevated but non-significant risks of T2D regardless of whether they met sleep duration guidelines.”
Promoting healthy sleep patterns for diabetes prevention: joint effects of sleep regularity and sleep duration in a prospective Chinese cohort. BMC Public Health
Who: 8,974 Chinese adults aged 40-79 in a national medical insurance database, mean age about 59.6, 44.6% male, without prevalent type 2 diabetes
PMID 41239287
other primary study · 2024 · landmark
“Notably, sleep regularity was a stronger predictor of all-cause mortality than sleep duration.”
Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study. Sleep
Who: UK Biobank adults with accelerometer data; mean age 62.8, 55.0% female, 97.2% white
PMID 37738616
other primary study · 2025
“Collectively, these findings highlight that maintaining regular sleep–wake cycles may be equally or potentially more important than achieving recommended sleep duration.”
Regular sleep patterns, not just duration, critical for mental health: association of accelerometer-derived sleep regularity with incident depression and anxiety. Psychol Med
Who: UK Biobank participants without depression or anxiety at baseline who wore a wrist accelerometer for 7 days; cohort recruited at ages 38-73 years; mean age 61.53 years, 54.75% female, 96.81% White
PMID 40814280
other primary study · 2025
“Sleep regularity showed an inverse association with incident dementia among those with non-optimal sleep duration, while no significant association was observed among those with optimal sleep duration.”
Dose-response associations of device-measured sleep regularity and duration with incident dementia in 82391 UK adults. BMC Public Health
Who: 82,391 UK Biobank accelerometry sub-study participants, mean (SD) age 62.4 (7.7) years, 55.9% female, 93.6% White, without diagnosed dementia before accelerometer wear
PMID 39920677
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