Your Nighttime Blood Pressure Could Be Silently Damaging Your Kidneys

Even slightly elevated blood pressure during sleep can significantly accelerate chronic kidney disease (CKD) progression, according to new research involving 2,418 patients. The study found that people with stage I nocturnal hypertension—blood pressure readings of 110-120/65-70 mmHg during sleep—had 2.49 times higher risk of kidney complications compared to those with normal nighttime blood pressure.

Why Does Nighttime Blood Pressure Matter More?

Unlike daytime blood pressure checks at your doctor's office, nighttime readings provide a more complete picture of cardiovascular risk. The study, published in JAMA Network Open, tracked participants for nearly four years and found striking differences in kidney outcomes based on sleep-time blood pressure levels.

Researchers categorized participants into three groups based on their nocturnal blood pressure readings:

• No Hypertension: Blood pressure below 110/65 mmHg (18% of participants)
• Stage I Hypertension: Blood pressure 110-120/65-70 mmHg (14.3% of participants)
• Stage II Hypertension: Blood pressure above 120/70 mmHg (67.7% of participants)

The results were concerning: while those with no hypertension and stage I hypertension had similar rates of kidney problems initially (29.1 and 28.6 cases per 1,000 people yearly), stage II hypertension patients experienced much higher rates at 63.7 cases per 1,000 people yearly.

What Types of Nighttime High Blood Pressure Are Most Dangerous?

The research revealed that different patterns of nocturnal hypertension carry varying levels of risk. Among the participants, 13.4% had isolated high bottom numbers (diastolic), 2.7% had isolated high top numbers (systolic), and 65.9% had both numbers elevated during sleep.

"Clinicians should avoid dismissing nocturnal stage I hypertension in non-dialysis CKD patients, since it is associated with renal outcomes," said senior author Dr. Xinying Jiang of Sun Yat-sen University in China.

The study found that having both systolic and diastolic hypertension during sleep carried the highest risk, with participants being 5.61 times more likely to experience kidney complications. Even isolated diastolic hypertension nearly tripled the risk at 2.88 times higher likelihood.

Should Older Adults Worry About Low Nighttime Blood Pressure?

Interestingly, the research uncovered a concerning pattern in patients aged 65 and older. Unlike younger participants, older adults with very low nocturnal blood pressure (below 110/65 mmHg) actually had a 5.50 times higher risk of kidney problems compared to those with stage I hypertension.

"This suggests that excessively low nocturnal blood pressure may be detrimental and increase the risk of adverse events in older patients with CKD," the researchers noted. However, they cautioned that the small sample size prevents firm conclusions about this finding.

The challenge extends beyond measurement to patient engagement. A separate study found that only 34.8% of high-risk patients consistently monitored their blood pressure at home, despite being provided with personal support and equipment. Nearly one-third never transmitted a single reading.

"Hypertension is largely asymptomatic, and the perceived immediate benefit of repeated blood pressure measurements is often low for patients, even when long-term risk is high," explained Dr. Ozan Unlu of Brigham and Women's Hospital.