Real-World Data Reveal Inconsistency in Sleep Duration

A study published in Sleep Health highlighted the considerable number of adults who experience insufficient and irregular amounts of sleep. However, the authors noted, these figures cannot account for differing individual sleep needs.

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The consistency and amount of sleep someone gets per night are important factors in overall individual health. As the authors of the present study note, an average of less than 6 hours of sleep per night has been correlated with higher rates of all-cause mortality, as well as various health conditions such as cardiovascular disease, obesity, and hypertension. Interestingly, getting more than 9 hours per night on average has also been linked to mortality risks and other health detriments such as diabetes, stroke, and more. The impacts of one’s sleep compound over time; the wealth of research on these effects has determined that the optimal amount of sleep for adult health falls between an average of 7 and 9 hours per night.

“The overwhelming majority of evidence to date regarding typical sleep durations in naturalistic environments is derived from self-report measures,” the authors write. Studies conducted with device-based tracking methods have the opportunity to analyze sleep durations, irregularities, and other factors with more accuracy and for longer durations of time. Given the benefits of this approach, and the important implications of sleep for overall health, researchers gathered device-based sleep data from more than 67,000 adults across the globe over a period of 9 months. Their analysis derived figures on average sleep duration and sleep variability to determine how many adults from this population met the standards for recommended sleep patterns.

Between July 2020 and March 2021, a total of 67,254 adults participated and were given under-mattress sleep sensor devices. Eligibility for the study required over 4 sleep recordings a week—and over 28 total—for participation.

The mean sleep duration across all participants was 7.5 hours per night. Overall, female participants demonstrated significantly longer sleep durations on average compared with males (mean difference, 0.37 hours; 95% CI, 0.32-0.43) and 31% of participants exhibited average durations outside the recommended range of 7 to 9 hours. When analyzed according to age group, patients between the ages of 40 and 65 years exhibited less overall sleep compared with patients aged 18 to 25 years and older than 65 years, on average. The authors note that the effects of sex and age on sleep duration were statistically significant (P < .01).

Only 15% of participants got the recommended 7 to 9 hours of sleep in at least 70% of nights (which equates to 5 nights out of the week) and only 2% achieved this mark for 85% of nights. In 30% to 40% of nights, participants slept for a duration outside of their average, demonstrating the degree of variability they experienced in their sleep schedules. The authors noted that sleep durations increased on the weekends, wherein 72% of participants had nights of 7 to 9 hours of sleep compared with a rate of 61% during the weekdays (mean difference, 11%; 95% CI, 10%-12%; P < .001). On average, adults slept 28 minutes longer on the weekend (95% CI, 27-29).

In concluding, the authors address the intricacies of sleep studies, sleep data, and individual variability: “While it is widely accepted that people need 7-9 hours per night for optimal daytime function and long-term health, it is also acknowledged that individuals have variable sleep requirements and habits . . . Consideration of sleep need and methods to evaluate it at the individual level will be required to determine whether any particular individual is acutely or chronically getting enough sleep.”

Reference

Scott H, Naik G, Lechat B, et al. Are we getting enough sleep? frequent irregular sleep found in an analysis of over 11 million nights of objective in-home sleep data. Sleep Health. Published online December 8, 2023. doi:10.1016/j.sleh.2023.10.016