Research paper · RP16

Sleep Is a Regulation Skill

Sleep is sold as a mood upgrade. The experimental record for healthy adults is thinner than the slogan. A pooled Hedges g for next-day emotion regulation was not computed: fewer than five randomised trials shared a common regulation endpoint after a sleep-improving programme in adults without diagnosed insomnia. The best-powered trial that measured both affect and regulation strategies (n = 72) found a small next-day drop in negative emotion (interaction d = 0.20) and no change in reappraisal, suppression or related strategy use. This PRISMA-2020 systematic review searched PubMed, PsycINFO, Scopus, Web of Science, Google Scholar, CTRI, ClinicalTrials.gov and OSF (2005–2026) for randomised or controlled trials of sleep extension, sleep hygiene or non-clinical cognitive-behavioural sleep components. Eligible outcomes were emotion-regulation measures, irritability, and positive or negative affect, preferably next day. Diagnosed-insomnia samples were excluded. Nine studies inform the narrative. In short sleepers, adding about 45–90 minutes of sleep opportunity for a week can lift next-day affect by a small amount and can lift flourishing and gratitude. In already-adequate sleepers, pushing time in bed by three hours can worsen mood. Emotion-regulation strategy use — the skill of reappraising a rude email rather than merely feeling less grim — has been tested in one eligible randomised trial and did not move. A large field experiment in Chennai found that 27 extra minutes of fragmented night sleep did not improve well-being; a protected workplace nap did. Prior reviews show the other arrow clearly: sleep loss cuts positive affect and adaptive regulation. Improving sleep quality in mixed and clinical samples improves mental-health symptoms by about half a standard deviation. Those numbers do not licence a claim that healthy Indian professionals will reappraise better tomorrow if they simply go to bed earlier tonight. Certainty is very low for regulation, low for affect, and insufficient for irritability. The honest product for a workplace programme is a sleep-opportunity rep plus a separate regulation rep, not a bundled promise.