Nighttime Urination May Worsen Insomnia, Study Finds

Waking up in the middle of the night to urinate was associated with worsening of sleep problems in older adults with insomnia, according to a Stanford University study.

Insomnia may not be the only reason that you’re tired in the morning — your bladder could be part of the problem too. Older people who have to get up and go in the middle of the night face heightened insomnia symptoms, according to a Stanford University study published in the Journal of Clinical Sleep Medicine.

Nocturia, the need to wake up in the night to urinate, is a condition that commonly plagues the elderly. The bladder disorder is associated with simply drinking too much liquid as well as with serious medical conditions — such as sleep apnea, bladder infections, or even prostate cancer.

Previous research had found a link between insomnia symptoms and nocturia, but data used in those studies relied on subjective information provided by patients.

Researchers at Stanford University decided to study seniors who had nocturia and insomnia by gathering both subjective and objective data. Patients kept sleep logs to gather the subjective analysis, and they wore actigraph units — small devices that resemble a watch and measure movement during sleep — to gather objective data.

All 147 volunteers (55 men, 92 women) were asked to fill out the sleep logs for two weeks. A subset of 60 people was asked to wear an actigraph unit on their wrist for an additional week. Subjects determined their level of “restedness” using a scale of 1 to 7 (1 being “not at all rested,” and 7 being “very rested”).

Software in the actigraph units evaluated sleep efficiency — determined using this ratio: (time in bed – time awake) / time in bed — and the number and length of nighttime waking episodes.

The researchers found that the actigraph group had a sleep efficiency level of 79 percent, meaning this group spent more than three hours asleep in bed for approximately every one hour spent awake. The sleep log group reported a similarly poor sleep efficiency level — 68 percent. (The average sleep efficiency level for someone without insomnia is 85 percent to 90 percent.)

Across both groups, 54 percent of all nocturnal awakenings were because of the need to urinate. Volunteers reported 1.4 trips to the bathroom per night, and 2.4 nocturnal awakenings. On the 1 to 7 sleep scale, subjects averaged a 3.8 level of “restedness”.

“Our data indicate that toileting at night is a common occurrence in older individuals with insomnia,” the study concluded. “(It is) significantly associated with the amount of wakefulness occurring during the night and decreasing subjective restedness after sleep.”

Still open is the question of whether the urge to urinate causes awakening, or awakening is an independent variable followed by the urge to urinate.

“The results raise the clinical question of treating nocturia to help individuals with insomnia,” said Jamie Zeitzer, PhD, the study’s lead author, in a press release. “That is, could much of the insomnia or poor sleep that occurs in older individuals be alleviated by treatment of nocturia? Of course, the opposite is quite possible — that proper treatment of insomnia might reduce the occurrence of nocturia as well.”

By Jeffrey Kopman