<p>Circadian rhythm, which governs sleep–wake regulation patterns, is influenced by circadian process and homeostatic process. The sleep stage starts from the Non-Rapid Eye Movement (NREM) stage and then transitions to the Rapid Eye Movement (REM) stage; interaction between the stages contributes to characterizing the depth of sleep and sleep disturbances. Two Polysomnography datasets have been used to analyse the influence of sleep variables and the mediating effect. The first meta-analysis focuses on concepts of sleep onset latency under exogenous light conditions. The outcome state, "wake after sleep onset latency", demonstrates a partial mediation by the mediator variable "total sleep time" with sleep onset latency as the predictor variable. The second dataset calculates the percentages of REM sleep and NREM sleep duration, specifically Stage 2 and Stage 3, using U-Sleep. Mediation analysis is done to determine the impact of lighter sleep stage NREM Stage 2 on restorative sleep stage (REM), with NREM Stage 3 as an intervention variable. The results indicate that 6.1% of proportion mediated by the NREM 3 stage is found on the outcome variable of REM. The contribution of sleep disorders in the presence of light and the restorative process involved in sleep stages are analysed with mediating factor of the target variable to its outcome in both the meta-analysis. Mediation analysis assessed the path dependence of the selected sleep variables and its proportion mediated.</p>