Sleep duration, chronotype, health and lifestyle factors affect cognition [pdf]
New research on UK Biobank data links “normal” sleep duration (7–9 hours) and evening chronotypes (“night owls”) with slightly better cognitive performance, while very long sleep is associated with worse scores. Commenters highlight that correlations around alcohol are especially murky: people who completely abstain show lower cognitive scores than moderate drinkers, but this likely reflects confounding factors such as ex-alcoholics, health status, religion, or socioeconomic background rather than any true benefit from alcohol. The thread also touches on how work schedules, commuting, genetics, and sleep quality complicate simple prescriptions about the “right” amount or timing of sleep.
Alcohol consumption and cognition
- Many note the study finds abstainers score lower cognitively than drinkers; this clashes with other research linking alcohol to brain harm.
- Several argue this is likely confounded:
- Abstainers may include former heavy drinkers or people who quit due to illness.
- People with serious health problems or lower income may drink less.
- Cultural and religious abstinence (e.g., in “dry” cultures) complicates interpretation.
- Some see weekly moderate drinking as possibly tied to social connections and novelty-seeking, which might track with cognition, but emphasize this is correlation only.
- Others insist there’s no plausible long‑term cognitive benefit of alcohol, despite these associations.
Sleep duration, quality, and practicality
- Commenters accept that 7–9 hours is “normal” physiologically, but many say this is hard to achieve with commuting, kids, and modern work.
- Several report functioning well on 6.5–7 hours and think the 8‑hour target is overstated; others track sleep carefully and find more sleep clearly improves performance and recovery.
- Some note that very long sleep often coincides with poor sleep quality, prior deprivation, depression, or illness.
- Confusion that the paper finds little link between subjective sleep quality and cognition; people cite other work and athletic experience where sleep quality strongly affects performance.
Chronotype (night owls vs larks)
- Night owls in the thread often feel more productive and creative late at night, citing fewer distractions and personal history.
- Others say they work best in early morning quiet, or that their chronotype shifted with age or kids.
- Consensus: forcing people to work against their chronotype feels harmful; any cognitive differences may come from social schedules misaligned with biology.
Methodological and interpretation concerns
- Multiple commenters stress correlation vs causation, “just‑so stories,” and the need to control for ex‑drinkers, health status, exercise, and socio‑cultural factors.
- Some think mixed findings on alcohol and sleep quality imply subtle or weak effects rather than clear causal stories.
Other factors discussed
- Personal reports on creatine, caffeine (including “coffee then nap”), nasal breathing, deviated septum, and sleep apnea highlight many unmeasured variables that might affect cognition and sleep.