For people with overactive bladder problems, cutting fluid intake by 25 percent can improves symptoms substantially, new research from the UK shows.

An overactive bladder causes a person to urinate frequently, often urgently. There may or may not be some leakage because of the urgency. Bladder infections, bladder cancer and bladder stones can produce the same symptoms, Dr. Hashim Hashim, one of the study’s authors, told Reuters Health, so these conditions must be ruled out before a diagnosis of overactive bladder can be made.

While people are frequently told to cut down on the amount they drink in order to control overactive bladder, evidence for the effectiveness of this approach is lacking, note Hashim and Dr. Paul Abrams at Southmead Hospital in Bristol. On the other hand, they add, people are often instructed to drink more fluids to improve their general health.

To investigate how manipulating fluid intake might affect overactive bladder symptoms, the researchers had 24 people with the condition drink 25 percent less than normal, 50 percent less than normal, 25 percent more than normal, or 50 percent more than normal, each for four days in a row, alternating with two days of normal fluid consumption.

As reported in the medical journal BJU International, cutting fluid intake by a quarter led to a 23 percent reduction in urinary frequency, 34 percent less urgency, and a 7 percent reduction in nighttime urination. Eighty three percent of the study participants said the 25 percent fluid reduction was most helpful to them.

People had a more difficult time cutting their fluid intake by half. Four people felt thirsty and two had headaches while trying to halve their fluid intake, while just one person had a headache when reducing fluid intake by 25 percent.

When the study participants drank 25 percent or 50 percent more than they usually did, their daytime urinary frequency increased.

The standard recommendation for fluid intake for a 70 kilogram (150 pound) person is 1.6 liters (54 ounces), Hashim said, but many people forget that fruit and vegetables contain a substantial amount of water; people typically take in 300 to 500 milliliters (10 to 17 ounces) of liquid from food daily.

People with overactive bladder who are drinking more than a liter of fluids may want to try reducing their fluid intake by 25 percent, he advised, but anyone who is drinking less than a liter should not. Drinking too little can cause the urine to become overly concentrated, he explained, which can also be irritating to the bladder.

Another key to managing an overactive bladder, Hashim said, is the use of a frequency-volume chart to keep track of how often one urinates and how much urine is produced. This can give people a clear sense of how much of a problem they have, according to the researcher, and also provide objective information on whether or not treatment is working.

SOURCE: BJU International, July 2008.