Fig 3: Group averages of salivary melatonin levels.

Closed circles represent saliva samples collected during the Baseline night (Day 8) and open circles represent those collected on the Final night of the study protocol (Day 10). Error bars denote standard error. Melatonin levels on Day 10 were significantly lower than at the same clock time on Day 8 at 50 min, 30 min, and 10 min before habitual bedtime, as well as 20 min and 50 min after habitual bedtime.