White Coat, Black Art·DR. GOLDMAN'S BLOG

Night time urination could mean your blood pressure's up

If you've been getting up to pee at night a bit more often lately, you might want to see your GP.
Cutting back on salt could reduce the need to void at night and lower blood pressure. (Adam Berry/Getty)

One in four Canadians is dissatisfied with the sleep they get. That's according to Statistics Canada. Some people sleep poorly because they have a need to answer nature's call. A new study concludes that a nightly trip to the loo might mean your health is at risk.

That's according to a study by researchers in Japan. They studied 1,882 people who had an annual health check that included blood pressure measurements. Of the 1,882 who filled out a health questionnaire, 1,295 got up to pee at least once a night on average. Compared to those who slept all night without going to the bathroom, those who got up to urinate at least once per night had 1.4 times greater odds of having high blood pressure. The greater the number of times per night that the person had to go to the bathroom, the greater the risk their blood pressure was high.

The results were presented at a combined meeting of the Japanese Circulation Society and the European Society of Cardiology held last week in Yokohama, Japan.

Researchers believe the connection between getting up to urinate at night and high blood pressure has to do with dietary salt intake. Previous studies have shown that a diet high in salt is associated with having to urinate more often at night.

Scientists have established a strong link between salt in the diet and high blood pressure. As well, studies have demonstrated the value in encouraging the entire population to cut back on salt and increase dietary potassium as part of an essential public health effort to prevent kidney disease, stroke, and heart disease.

A prior study (also from Japan) published in 2017 in the British Medical Journal found that cutting back on salt can also reduce the need to void at night.

So, you get two bangs for the buck: better sleep and lower blood pressure.

There are some compelling reasons to wonder if the results of a study conducted on the Japanese population may not be completely applicable in Canada. The average salt intake in Japan is 10 grams per day, and is related to the high consumption of salt-containing seafood and soy sauce. Researchers say that people who consume that much salt are highly sensitive to small increases in dietary salt.

By contrast, Health Canada says the average daily sodium intake among Canadians is 2,760 milligrams, which is just a bit higher than the established goal of 2,300 milligrams per day, but much lower than the average daily consumption in Japan.

Recent studies have suggested that salt intake is mainly associated with heart attacks and strokes in countries where the average salt intake is greater than 5 grams per day. Therefore, lowering salt in Canada should not have the same impact as in Japan.  

3 common sense remedies

Aside from blood pressure, there many other reasons for getting up at night to urinate. Most people over the age of 60 wake up to void one or more times during the night. Conditions that cause nighttime urination include heart failure, swelling of the legs and obstructive sleep apnea. A whole host of medications cause nighttime urination including diuretics. A bladder infection is a temporary cause of frequent urination with a burning sensation.

Other causes in the bladder include an overactive bladder, a blockage, or cancer. In men, an enlarged prostate is another frequent cause. Diabetes or a high fluid intake cause frequent urination night and day. Drinking too much fluid (especially caffeine beverages and alcohol) is another cause.

If getting up to pee at night is a new problem, try common sense remedies before seeing the doctor. Limit your fluid intake by not drinking any liquids after 6 p.m. Avoid foods and beverages that can irritate your bladder, including caffeine, alcohol, citrus juices, cranberry juice (it irritates the bladder), curries and other spicy foods, acidic foods like tomatoes, chocolate and artificial sweeteners.

You can also try urinating twice before retiring to bed. Urinate as per your usual nighttime ritual. Then, just before you turn out the lights, try to squeeze out another tablespoon or so of pee.

If these suggestions don't work, see your doctor. Don't assume that nighttime urination is just a sign of aging.


Dr. Brian Goldman is a veteran ER physician and an award-winning medical reporter. As host of CBC Radio’s White Coat, Black Art, he uses his proven knack for making sense of medical bafflegab to show listeners what really goes on at hospitals and clinics. He is the author of The Night Shift and The Power of Kindness: Why Empathy is Essential in Everyday Life.


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