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The effects of day‐time exogenous melatonin administration on cardiac autonomic activity
Author(s) -
Harris Angela S.,
Burgess Helen J.,
Dawson Drew
Publication year - 2001
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1034/j.1600-079x.2001.310302.x
Subject(s) - melatonin , medicine , endocrinology , heart rate , thermoregulation , placebo , autonomic nervous system , heart rate variability , circadian rhythm , blood pressure , alternative medicine , pathology
Melatonin has a functional role in the nocturnal regulation of sleep and thermoregulation. In addition to its action on peripheral receptors, melatonin may act by altering autonomic activity. To determine the effect of melatonin on cardiac autonomic activity, 5 mg of melatonin or placebo was orally administered to 12 young subjects at 14:00 hr, in a repeated measures design. Melatonin decreased sleep onset latency to Stage 2 sleep by 4.92±1.81 min (measured by Multiple Sleep Latency Tests), rectal temperature by 0.19±0.05°C, and increased foot temperature by 0.74±0.45°C (all P <0.05). Melatonin decreased heart rate by 3.66±1.68 beats/min ( P <0.05) and pre‐ejection period (measure of cardiac sympathetic activity) by 16.48±4.28 ms ( P <0.05), but had no effect on respiratory sinus arrhythmia (measure of cardiac parasympathetic activity) ( P >0.05). As the decrease in pre‐ejection period is likely to have resulted from a decrease in blood pressure, these results do not confirm an effect of melatonin on cardiac sympathetic activity. However, the results do clearly indicate that melatonin is unlikely to drive the previously observed presleep increase in cardiac parasympathetic activity.