Too many nightcaps are unlikely to lead to a good night's sleep
Many people do not realise drinking alcohol can disturb a good night's sleep by interfering with the brain, a government-funded poll suggests.
Almost half of 2,000 drinkers surveyed reported fatigue the day after drinking more than the recommended daily limit.
But some 58% of those questioned were unaware that sleep problems could be caused by exceeding the limit.
The survey by YouGov was carried out for the Know Your Limits campaign, started three years ago.
Men are advised to drink no more than four units a day - the equivalent of two pints of regular-strength beer, and women no more than three units - the equivalent of a large, 250ml glass of wine.
According to the poll's findings, many people did not know that the dehydration caused by drinking could interfere with their sleep.
Alcohol stops the brain from releasing vasopressin, a chemical which tells the kidneys to reabsorb water that would otherwise end up in the bladder. Without this signal, the drinker needs more frequent trips to the toilet.
The loss of this water can also lead to a headache emanating from the inner lining of the skull.
In addition, alcohol disrupts the "REM" stage of sleep, which is thought necessary for a deep and effective slumber.
After drinking the body tends to fall straight into a deep sleep, and only enters the REM stage once the alcohol has been metabolised.
As the body wakes more easily from REM sleep, many drinkers find they stir early in the morning without feeling as if they have slept properly.
The Department of Health is urging all drinkers to avail themselves of the NHS's online interactive units calculator for a "better night's sleep and a happier brain".
Jessica Alexander, spokesperson for the Sleep Council, said: "Although many people may feel alcohol helps them get off to sleep, it is also a major culprit for disrupting your night as it can interfere with the body's chemical processes needed for sound sleep.
"Waking up deprived of the vital sleep your body needs will leave you feeling drained and, if experienced night after night, can seriously affect your health and wellbeing.
"If you find yourself drinking above the recommended daily limits most days of the week, your body may be constantly trying to catch up and then it's likely you'll never feel fully alert or equipped to deal with the stresses and strains of daily life."