MELATONIN IMPROVES EVENING NAPPING

Twelve young adults were treated with either melatonin, 3 mg or 6 mg, or placebo, at two different times before an early evening nap (18.00- 20.00 h) according to a balanced double-blind Latin square design. Pol ysomnographic monitoring revealed that both dosages of melatonin signi ficantly shortened sleep latency and increased total sleep time in com parison to placebo, irrespective of the time of administration. Subjec ts also tended to assess their sleep as 'deeper' after melatonin treat ment. Based on previous data and the present results, it was concluded that exogenous melatonin exerts hypnotic effects only when circulatin g levels of endogenous melatonin are low.