Caffeine Intake and Sleep Quality: 428 Working Adults, Source by Source
A 2026 cross-sectional study involving 428 employed adults found that poor sleepers reported a median 292.8 mg/day of caffeine, compared with 176.1 mg/day among good sleepers, and total caffeine intake still predicted higher Pittsburgh Sleep Quality Index scores after adjustment (β = 0.147, p = 0.003). The source breakdown is the useful part: black coffee, …