Exogenous melatonin's effect on salivary cortisol and amylase: A randomized controlled trial.

This study aimed to examine the effect of acute exogenous melatonin administration on salivary cortisol and alpha-amylase (sCort and sAA) as representatives of the HPA axis and the sympathetic nervous system, respectively. A single-dose prolonged-release melatonin (2 mg) or a placebo tablet was given to healthy volunteers (n = 64) at 20:00 h in a crossover design. The saliva was collected at six time points (20:00, 21:00, awakening, 30 min after awakening, 10:00, and 12:00 h) and was measured for sCort, sAA, and salivary melatonin (sMT) levels. Pulse rates and sleep parameters were also collected. Melatonin was effective in improving sleep onset latency by 7:04 min (p = .037) and increasing total sleep time by 24 min (p = .006). Participants with poor baseline sleep quality responded more strongly to melatonin than participants with normal baseline sleep quality as they reported more satisfaction in having adequate sleep (p = .017). Melatonin administration resulted in higher sCort levels at awakening time point (p = .023) and a tendency of lower sAA levels but these were not significant. Melatonin ingestion at 20:00 h resulted in a marked increase in sMT levels at 21:00 h and remained higher than baseline up to at least 10:00 h (p < .001). Melatonin increases sCort levels at certain time point with a tendency to lower sAA levels. These opposing effects of melatonin suggested a complex interplay between melatonin and these biomarkers. Also, the results confirmed the positive acute effect of a single-dose melatonin on sleep quality.

The Use of Coffee Aroma for Stress Reduction in Postgraduate Dental Students.

OBJECTIVES: This study aimed to investigate the potential reduction of academic stress related to a graded oral presentation in postgraduate dental students using coffee aromatherapy. METHODS: Healthy postgraduate dental students in a seminar class were divided into coffee (n = 32) and control (n = 26) groups. There were 3 modes of aroma distribution: personal distribution with a coffee pad attached to a lanyard, a lanyard plus a personal fan for ventilation of the aroma, and the typical method of the diffuser to spread the aroma in the ambient air. Stress markers comprised levels of salivary alpha-amylase (sAA), cortisol (sCort), and chromogranin A (sCgA). Pulse rates were also measured. RESULTS: Levels of sAA increased 176.62% ± 30.26% between pre- and postpresentation in the control group. Inhaling coffee aroma during the presentation period significantly ameliorated sAA increase at 81.02% ± 14.90% (P = .015). sCort levels tended to decrease in the coffee group, but not significantly. Surprisingly, sCgA levels increased more in the coffee group. Also, pulse rates decreased in the coffee group (-2.07 ± 2.81 bpm) and increased in the control group (6.90 ± 3.22 bpm; P = .035). Subgroup analysis did not reveal differences in salivary markers amongst the 3 aroma distribution modes. CONCLUSIONS: Coffee aroma could have an anxiolytic effect on postgraduate dental students, as evidenced by changes in sAA levels and pulse rates. Personal aroma distribution was also a useful and effective mode of aromatherapy.