Effects of caffeine consumption timing on subjective and objective sleep onset and dream recall in Indian young adults: a mixed-methods study with cultural and occupational moderators

Abstract Background Meta-analyses confirm caffeine’s sleep-disrupting effects, but qualitative insights into perceived disruptions in non-Western, high-pressure contexts remain scarce.

Aim: To examine how the timing of caffeine intake, culturally embedded in chai consumption, influences subjective and objective sleep onset latency and dream recall among Indian young adults, with particular attention to occupational differences between students vs. professionals.

Methods: Sequential mixed-methods cross-sectional study was conducted among 200 healthy Indian young adults aged 18–35 years (80 students, 120 professionals) from Maharashtra, India. Phase 1: semi-structured interviews ( N = 200). Phase 2: validated questionnaires (Pittsburgh Sleep Quality Index, Morningness-Eveningness Questionnaire, Caffeine Consumption Questionnaire) and 7-night actigraphy ( n = 50 subset). Thematic analysis was performed using NVivo 12; quantitative data were analysed using SPSS v.26.

Results: Late caffeine intake (after 6 PM) (last intake after 18:00 h) was reported by 57.5% ( n = 115), primarily driven by academic deadlines among students (67.5%) and extended work hours among professionals (50.8%). Participants with late intake reported markedly longer perceived sleep onset latency (46.2 ± 12.1 min) than those with early/no late intake ≤ 18:00 h or none after 18:00 h intake (19.8 ± 6.3 min; p < 0.001). Actigraphy confirmed objective delays (29.4 vs. 16.1 min; r = 0.68). Dream recall frequency dropped from 5.6 ± 1.1 to 2.9 ± 1.4 days per week with late intake, inversely correlated with wake after sleep onset ( r = − 0.61, p < 0.001). Students showed greater vulnerability (β = 1.42, p = 0.002).

Conclusion: In Indian young adults, caffeine consumed after 6 PM — culturally tied to chai and deadline-driven lifestyles — significantly prolongs perceived and objective sleep onset and reduces dream recall through increased sleep fragmentation. Students are at highest risk. Shifting intake earlier emerges as a simple, culturally acceptable intervention.