From the Guidelines
Sleeping at 10 PM is likely to be more beneficial for sleep quality and deep sleep compared to sleeping at 11 PM, even if the total sleep hours remain the same, as it aligns better with the natural circadian rhythm. This is supported by a recent study published in 2022, which suggests that the timing of sleep, in addition to the duration, can have significant effects on health outcomes 1. The study found that later sleep timing is associated with poorer emotional regulation, lower cognitive functioning, and poorer sleep quality in children and adolescents. While the study did not provide a specific bedtime recommendation due to modest evidence quality, it intuitively suggests that earlier bedtimes, such as 10 PM, may be beneficial for achieving the recommended sleep duration of 9-12 hours.
Some key points to consider:
- The American Academy of Sleep Medicine recommends 9-12 hours of sleep daily for children aged 6-12 years, and insufficient sleep duration can lead to various health problems 1.
- The consistency of sleep onset and timing can contribute to health outcomes, with later sleep timing associated with obesity, type 2 diabetes, and cardiovascular diseases in adults and adolescents 1.
- Individual chronotypes vary, and some people may be natural "night owls" with optimal sleep times later than others.
- Maintaining a consistent sleep schedule, including weekends, is crucial for regulating the body's internal clock and optimizing sleep quality.
Overall, while individual variations exist, sleeping at 10 PM is likely a better choice than 11 PM for most people, as it aligns with the natural circadian rhythm and may lead to improved sleep quality and deep sleep. This is supported by the most recent and highest-quality study available, which emphasizes the importance of sleep timing in addition to duration 1.
From the Research
Sleep Quality and Deep Sleep
The difference in sleep quality or deep sleep between sleeping at 10 pm vs 11 pm, given the same total sleep hours, can be understood through the lens of circadian rhythms and sleep timing.
- Research suggests that the timing of sleep is crucial, with earlier sleep timing and regularity in sleep patterns being favourably associated with health 2.
- The body's intrinsic clock, regulated by the suprachiasmatic nucleus (SCN), plays a significant role in sleep-wake cycles, and misalignment of the circadian clock with the environmental cycle may result in sleep disorders 3.
- While the specific comparison between 10 pm and 11 pm sleep times is not directly addressed in the provided studies, the general consensus is that earlier sleep timing tends to have positive effects on health and sleep quality.
Factors Influencing Sleep Quality
Several factors can influence sleep quality, including:
- Light exposure: Nocturnal light can alter circadian rhythms and sleep in humans, but light can also be used therapeutically to improve sleep and mood 4.
- Caffeine consumption: Drinking caffeinated coffee can decrease sleep quality and quantity, and also decrease melatonin secretion 5.
- Sleep consistency and regularity: Irregular sleep patterns and social jetlag are associated with adverse health outcomes, while consistent bedtimes and wake-up times are favourably associated with health 2.
Sleep Duration and Timing
The relationship between sleep duration, timing, and next-day physical activity has been explored, showing that:
- Longer sleep duration and later sleep onset timing are associated with decreased physical activity 6.
- Sleeping shorter-than-usual and falling asleep earlier-than-usual can be associated with increased next-day physical activity 6. These findings suggest that sleep timing and duration have complex interactions with other health behaviors and outcomes.