Was sleep quality or sleep duration more closely linked to productivity?

Details

Insufficient or poor-quality sleep is widely assumed to impair daily functioning, but it is unclear whether sleep duration or perceived sleep quality is more closely related to everyday productivity outside clinical and laboratory settings. Researchers explored this question in a cross-sectional online survey of 349 respondents, including students, employed and self-employed people, and other respondents; 12 were under 18. Participants reported weekday and weekend sleep duration in four ordered bands, sleep quality on a single 1–5 item, daytime tiredness, stress, low motivation and productivity on a single 0–10 item.

The researchers examined associations using Spearman correlations, Kruskal-Wallis and Jonckheere-Terpstra tests, and multiple linear regression adjusted for age, gender, occupation and work/study hours. They also performed residual diagnostics and sensitivity analyses. Mean productivity was 6.31 (SD 2.43).

Sleep quality was moderately correlated with productivity (ρ = 0.40, 95% CI 0.30–0.50) and remained a strong independent correlate in the adjusted model (B = 0.89, 95% CI 0.70–1.09; adjusted R² = 0.21). Sleep duration had a negligible association with productivity (weekday ρ = 0.12, weekend ρ = 0.11; about 1% shared variance), which was not significant after adjustment. Daytime tiredness had a small, non-monotonic inverse association with productivity (ρ = −0.12).

In this convenience sample, perceived sleep quality, rather than reported sleep duration, was the main correlate of self-rated productivity. Single-item self-reports, common-method variance and possible reverse causality limit inference. The authors recommend replication using validated instruments and longitudinal designs.