A research study that was so quirky it won a 2011 Ig Nobel Prize for medicine, has found that the urgent need to urinate has the same negative effect on attention and working memory as having a 0.05% blood alcohol level or major sleep deprivation.
Lead author of "The effect of acute increase in urge to void on cognitive function in healthy adults", which was published in the journal of Neurology and Urodynamics, is Caulfield Hospital's aged psychiatry research co-ordinator Dr Matthew Lewis.
Dr Lewis says the pilot study revealed that cognition remained relatively normal until the point where a person absolutely positively needs to go to the toilet.
"At that urgent stage, cognition for the attention task was at a level of impairment equivalent to 0.05 blood alcohol content or being awake for 24 hours and for the working memory task, cognition levels exceeded that level of impairment," Dr Lewis said.
Urgently needing to urinate did not decrease the accuracy of performance on any test. But it reduced the speed with which healthy adults could make decisions on the basis of available visual information or when information had to be retrieved from working memory. As soon as they went to the toilet, cognitive performance returned to normal. The one task that was not affected was one testing psychomotor function.
Although this was only a preliminary study, results are interesting for those in workplaces where it is necessary to prolong toilet visits, such as those where shift and task demands may make it impractical to go to the toilet when their bladder is full.
"We believe that it is the pain associated with ‘holding on' and the distraction associated with that which affects individuals on tasks," Dr Lewis said.
"Pain will interrupt normal behaviour until it is removed. So tasks that require continuous and complex attention, such as driving, could be negatively affected and the likelihood of accidents could be increased, like they are when alcohol or sustained wakefulness is involved."
This pilot study, which was conducted with Australian company CogState (who make computerised tests of cognition), involved eight healthy adults who did three computerised tasks to measure cognitive function. Each participant consumed 250ml of water every 15minutes. It took an average of 140 minutes and 2218mls of water for participants to get to the point where they could no longer resist going to the toilet.
The findings have led to the need for greater study, Dr Lewis explained.
"We believe further investigation of interactions between the voluntary control of bladder function and cognitive function is warranted incorporating a more representative sample, with a more complete urodynamics assessment and to evaluate the effect of extreme need to urinate on other markers of accident risk such as in studies of performance in a driving simulator."
* Dr Lewis's study jointly took out the Ig Noble Prize for Medicine this year, awarded by the Improbable Research organisation in the US who hand out the awards at a gala ceremony at Harvard University each year. The Ig Nobel Prizes honour achievements that first make people laugh, and then make them think. The prizes are intended to celebrate the unusual, honour the imaginative and spur people's interest in science, medicine, and technology.