Sleep duration and regularity → Cognitive performance

Mechanism

Lim and Dinges (2010) pooled short-term deprivation studies. Vigilance and working memory fell. The identified object is hours asleep. This atlas will not let that smuggle income, mate value, or a title. Zimmerman and colleagues (2024) ran a randomized crossover in sixty-five adults who already slept 7 to 9 hours. Two six-week conditions: keep habitual bed and wake times, or delay bedtime by 1.5 hours. They used the NIH Toolbox and scored each endpoint against the first baseline so practice would not be mistaken for a sleep effect. List Sorting working memory and the Flanker task rose after the habitual weeks beyond that practice gain. After the short weeks they did not. Processing speed rose in both arms. Card-sort flexibility did not move. Santisteban, Brown, Ouimet, and Gruber (2019) cut one hour from habitual nights for six nights against a lamp with no known effect. Working memory capacity improved from baseline in the lamp arm and did not in the short-sleep arm. Sustained attention, response inhibition, and decision making did not change in either arm. Lo, Ong, Leong, Gooley, and Chee (2016) randomized fifty-six adolescents aged 15 to 19, from top high schools and not habitual short sleepers, in a boarding school. After three 9-hour nights, one arm had seven nights of 5-hour time in bed and the other kept 9 hours. A battery ran three times a day. Psychomotor Vigilance lapses rose night after night in the short arm. Verbal 1-back and 3-back sensitivity fell. Practice gains on mental arithmetic and symbol-digit were smaller than in the 9-hour arm. After two 9-hour recovery nights, vigilance and sleepiness were still worse than baseline, and processing speed still lagged the controls. The four papers are not the same exposure. The meta is acute deprivation. Zimmerman is six weeks of a modest bedtime delay. Santisteban is a one-hour adult week. Lo is a hard adolescent week. All still name time asleep.

Caveats

The meta is acute lab protocols, not a career trial. Recovery sleep reverses much of that deficit. Chronic restriction and shift work are related exposures, not that estimate. Zimmerman is sixty-five completers, mean age about 36, 89 percent women, already 7-to-9-hour sleepers without a diagnosed sleep disorder. Scores after the short arm did not fall below baseline; they failed to show the practice gain seen after habitual nights. Women using hormonal contraception were excluded. Santisteban is available here only as an abstract. The placebo was a lamp. Working memory was the task that moved. Attention, inhibition, and decision making did not. The abstract names 93 adults, mean age about 24, and does not name a sample size in the record we hold. Lo is fifty-six adolescents in a Singapore boarding school after the school year. Thirty were on 5-hour nights and 26 on 9-hour nights. The short arm woke two hours earlier and went to bed two hours later, so tests sat after a longer wake. They were not habitual short sleepers. Mood and sleepiness are not this page. Two recovery nights did not restore vigilance. None of these papers is a reason to prescribe a bedtime.

Effect

qualitative. Lim-Dinges meta: acute deprivation cuts vigilance and WM. Zimmerman N=65: 6-wk 7-9 h beat practice on WM and flanker. Santisteban: 6 nights minus 1 h cut WM, not attention. Lo N=56: 7 nights of 5 h TIB cut PVT and n-back.

Nodes

Named confounders

• Alcohol intake
• Ferritin

Papers

• A meta-analysis of the impact of short-term sleep deprivation on cognitive variables

  J. Lim, D. F. Dinges · 2010 · Psychological Bulletin

• The effects of insufficient sleep and adequate sleep on cognitive function in healthy adults.

  ME Zimmerman, G Benasi, C Hale, LK Yeung, J Cochran, AM Brickman, MP St-Onge · 2024 · Sleep health

• Cumulative mild partial sleep deprivation negatively impacts working memory capacity but not sustained attention, response inhibition, or decision making: a randomized controlled trial.

  JA Santisteban, TG Brown, MC Ouimet, R Gruber · 2019 · Sleep health

• Cognitive Performance, Sleepiness, and Mood in Partially Sleep Deprived Adolescents: The Need for Sleep Study.

  JC Lo, JL Ong, RL Leong, JJ Gooley, MW Chee · 2016 · Sleep