London: It`s often said a shot of whisky at night is one of the best ways to go to bed. But, now a study claims that a wee dram before bedtime can spoil one`s sleep.
An international team, led by Akita University in Japan, has carried out the study and found that downing alcoholic drinks before bedtime can cause insomnia and spoil a person`s nightcap, the `Daily Express` reported.
Researchers have based their findings on an analysis of student "guinea pigs" who were given a series of alcoholic drinks of different strengths an hour and 40 minutes before
going to bed.
Each time readings were taken that recorded activity in the heart and brain.
The researchers found that the alcohol resulted in sleeplessness and the disturbed nights left the students exhausted. The alcohol suppressed parasympathetic nerve activity -- the part of the "autonomic", or non-voluntary, nervous system that slows heart rate and aids digestion.
Known as the "rest and digest" nervous system, this helps maintain and restore energy.
Team leader Dr Yohei Sagawa of Akita University, said: "Although the first half of sleep after alcohol looks good drinking leads to insomnia rather than good sleep."
US colleague Dr Seiji Nishino added: "It is generally believed a nightcap may aid sleep, especially sleep initiation. This may be true for some who have small amounts of alcohol. However, large amounts interfere with sleep quality and the restorative role of sleep.
"These negative consequences may be much larger during chronic alcohol intake."
The findings have been published in the latest issue of the `Alcoholism: Clinical & Experimental Research` journal.