Those who make two or more trips to the lavatory in the night are costing the economy £4.5bn a year, research suggests.
The study warns that “nocturia” – waking up at least twice in the night to pay such a visit – is causing such fatigue that it is disrupting work productivity.
The research suggests that around 14 per cent of Britons suffers the plight – costing them an average of seven working days a year in abseenteism, or being at work while in suboptinal health.
Researchers said those whose sleep was disturbed by regular trips to the lavatory should turn to their GP, and check there was no underlying health problem which could be treated.
Repeated visits can be a sign of chronic health conditions such as kidney disease, diabetes and heart disease, and are most common in older men, where they can signal an enlarged prostate, or prostate cancer.
The international study by Rand international suggests that 9 million people in the UK suffer from nocturia. Among them are 5.7 million people of working age.
The authors of the report, commissioned by Ferring Pharmaceuticals, estimated that the impact of lost sleep as a result of such trips amounts to £4.5 billion a year.
Marco Hafner, lead researcher and senior economist said the findings should be treated as a “wake up” call for patients and medics.
He said: “Doctors and health practitioners often overlook nocturia as a potential health problem associated with sleep loss, and patients can delay reporting the condition until it becomes unbearable and substantially affects their wellbeing.”
More than half of of men and women above the age of 50 complain of frequently needing the toilet in the middle of the night, leading to fatigue, irritability and a groggy feeling in the morning.
Some scientists believe that lowering salt intake can reduce the number of bathroom trips.
A study of Japanese volunteers found that when they were asked to cut their salt by 25 per cent, from 10.7g to 8g a day, their average night time toilet expeditions fell from an average of 2.3 trips to 1.4 times.