Figure 3From: Effect of oral melatonin and wearing earplugs and eye masks on nocturnal sleep in healthy subjects in a simulated intensive care unit environment: which might be a more promising strategy for ICU sleep deprivation? Serum melatonin concentration time profiles for different study conditions on night 8. Serum melatonin levels were measured at the end of the study period for 9 h from 20:50 to 06:00. The graph depicts the nocturnal serum melatonin concentration. Points represent mean ± SD. Open circles, healthy subjects on simulated ICU noise and light (NL); solid circles, healthy subjects on NL plus placebo (NLP); solid triangles, healthy subjects on NL plus use of earplugs and eye masks (NLEE); solid squares, healthy subjects on NL plus melatonin (NLM): *P <0.05 at 22:00, 23:00, 0:00, 01:00, 02:00 and 03:00, respectively, for comparison between the NLM and NL nights.Back to article page