Figure 2: Salivary melatonin concentrations during waking hours following sleep at home or sleep in the lab. Daily profiles were assessed by having subjects provide multiple samples throughout the day, beginning immediately upon awakening and fi nishing prior to going to sleep. Samples were provided following sleep at home (Baseline), the 1st and 2nd nights in the sleep laboratory (Lab1 and Lab2) and again once subjects resumed sleeping at home (PostLab). †Statistically significant difference between both Lab nights and Baseline, P<0.01; ‡Statistically significant difference between both Lab nights and PostLab, P<0.05. *Statistically significant difference between both Lab nights and both home conditions, P<0.05.