People who reported waking up in the middle of the night to use the bathroom were 40 percent more likely to have hypertension, according to a study presented March 30 at the Japanese Circulation Society’s annual scientific meeting.
That association was present after adjusting for possible confounders in a population of 3,749 residents of Watari who had an annual checkup in 2017. Hypertension was defined as a blood pressure of at least 140/90 mm Hg or the use of antihypertensive medication.
“Our study indicates that if you need to urinate in the night—called nocturia—you may have elevated blood pressure and/or excess fluid in your body,” Satoshi Konno, MD, PhD, of the Division of Hypertension at Tohoku Rosai Hospital in Sendai, Japan, said in a press release. “If you continue to have nocturia, ask your doctor to check your blood pressure and salt intake.”
According to the release, the average salt intake in Japan is approximately 10 grams per day, more than double the four grams consumed by the average person in the rest of the world. People in Japan may also have blood pressures more sensitive to salt intake, meaning saltier diets would have a larger impact on their hypertension risk.
For these reasons, Konno said the results of the study might not apply to other populations. Also, the researchers couldn’t prove causality; lifestyle factors, ethnicity and genetic factors could also contribute to the association between nocturia and high blood pressure.
Nevertheless, those nighttime trips to the toilet are something to keep an eye on, particularly if they occur multiple times. The researchers found there was a significant increase in the risk of hypertension for each additional nocturia event per night.
“Early detection and management of hypertension are very important to prevent cardiovascular diseases,” Mutsuo Harada, press coordinator for the scientific meeting, said in the same release. “We should keep in mind that nocturia is not only caused by urinary organ problems but also by systemic diseases such as hypertension.”