Scientists Identify Overlooked Cause of High Blood Pressure Missed During Routine Testing - Video

Nighttime hormone surges may reveal a commonly missed cause of high blood pressure, according to research suggesting wearable monitoring could improve detection of primary aldosteronism.

Published in Science Translational Medicine, the study examined primary aldosteronism, a hormone disorder that may affect many people with hypertension. The condition occurs when the adrenal glands produce too much aldosterone, a hormone that helps control salt and water balance. It can increase the risk of heart disease and stroke.

Researchers monitored 60 patients for 24 hours using U-RHYTHM, a device developed at the University of Bristol. Worn around the waist, it collected hormone samples from the skin every 20 minutes while participants continued activities and slept at home.

Researchers measured aldosterone and related hormones, including 18-hydroxycortisol and 18-oxocortisol. They found that aldosterone was not consistently high throughout the day. Instead, some patients experienced repeated hormone bursts, including during sleep.

These nighttime surges are important because conventional testing usually relies on blood samples taken at specific times while patients are awake. A single test could therefore occur when hormone levels are temporarily lower and fail to detect the disorder.

The unusual hormone bursts were particularly pronounced in people whose condition was caused by a problem affecting one adrenal gland. Importantly, the abnormal pattern disappeared after the affected gland was surgically removed, supporting a link between the hormone pattern and the disease.

The researchers say continuous monitoring could help identify patients whose fluctuating hormone levels are missed by conventional testing. Earlier diagnosis could be valuable because primary aldosteronism can be treated and, in some cases, cured.

However, this was a proof-of-concept study involving only 60 patients. Larger studies are needed to determine how accurately wearable hormone monitoring can diagnose primary aldosteronism and whether it should become part of routine hypertension testing.

REFERENCE: Marianne A. Grytaas, et al.; Tissue corticosteroid rhythms are dysregulated predominantly during sleep in primary aldosteronism. Science Translational Medicine, 2026; 18 (864) DOI: 10.1126/scitranslmed.aeb7517