People who suffer from breathing difficulties while asleep are more likely to have to wake up at night to go to the bathroom, scientists have said. Treating them for obstructive sleep apnoea might have might also the unintended positive effect of reducing excessive urinating at nighttime, a phenomenon known as nocturia.
Most people can sleep uninterrupted for six to eight hours without needing to pee. In that time, the body produces less urine, but it is more concentrated.
However, some individuals, especially those over the age of 50 suffer from nocturia – it's estimated that more than half the men and women over that age are affected. This is particularly prevalent among patients with obstructive sleep apnea (see box).
When the condition is severe, patients can be treated by wearing a mask when they sleep. This device, called the "Continuous Positive Airway Pressure Mask" (CPAP mask), works by increasing the air pressure in the throat so that the airway doesn't collapse during sleep.
A study presented at the European Association of Urology conference in London by scientists from Maastricht University Medical Centre (the Netherlands) is the first show the true incidence of nocturia among sleep apnoea patients. The scientists also showed for the first time that wearing the mask could reduce the frequency of nighttime peeing.
Benefits of wearing a mask
Let by Dr Sajjad Rahnama'i the team worked with studied 256 patients – including 206 males and 50 females – who were treated for obstructive sleep apnoea with a CPAP mask.
Before receiving this treatment, the participants had answered questions about their health and habits, with 69% reporting nocturia. However, after they started using the mask, 2/3 of these patients said it reduced their need to pee at night.
The greatest benefits of the mask were seen in people with less severe nocturia. 32 of the 77 patients who previously reported "only" two episodes per night were able to sleep through the night with the treatment.
Professor Marcus Drake from Bristol University, who was not involved with the study, commented: "It may seem surprising that breathing problems can cause excessive urine production while asleep, but actually the problem is very real. To have a study showing the link, and the potential benefits of therapy, may help establish the treatment into routine clinical practice".
What is obstructive sleep apnoea?
The condition is quite common and occurs when the walls of the throat relax and narrow during sleep, interrupting normal breathing. It can lead to a number of serious health complications and regularly interrupt patients' sleep, with negative consequences on their quality of life.
Symptoms can include: loud snoring, noisy breathing and repeated short periods where breathing is interrupted by gasping or snorting. Two types of breathing interruptions are in fact characteristic of the condition:
Apnoea: The muscles and soft tissues in the throat relax and collapse sufficiently to cause a total blockage of the airway. The airflow is blocked for 10 seconds or more
Hypopnoea: The airway is partially blocked of the airway with a reduction of airflow of greater than 50% for 10 seconds or more.
It is has hard to pinpoint a single cause of obstructive sleep apnoea but a number of risk factors have been recognised. For instance, men seem to be more susceptible than women. Other factors include being overweight, being more than 40, alcohol consumption and smoking, having a large neck, or a family history of the disease. More information on the NHS website.