A Wearable Hormone Monitor Reveals a Hidden Cause of High Blood Pressure

Researchers using a wearable hormone-monitoring device have uncovered previously hidden patterns in primary aldosteronism, a potentially curable disorder that may affect as many as one in five people with high blood pressure.

The condition develops when the adrenal glands produce too much aldosterone, a hormone that helps regulate the body's salt, water and blood pressure balance. People with the condition face elevated risks of heart disease, stroke, diabetes and other serious health problems, yet diagnosis is frequently delayed because aldosterone naturally fluctuates, so a blood sample taken at a single moment can give an incomplete or misleading picture.

In a study published in the journal Science Translational Medicine, scientists from the University of Bristol and the University of Manchester in the UK, the University of Bergen in Norway, and partner institutions in Stockholm and Athens monitored 60 patients at home using a lightweight wearable device called U-RHYTHM. Worn at the waist and about the size of a mobile phone, it measured hormone levels from the skin every 20 minutes over a continuous 24-hour period, including while patients slept.

Rather than staying constantly elevated, aldosterone repeatedly climbed and fell, including a previously hidden pattern of nighttime hormone bursts that routine daytime blood tests would miss. At some points levels even dropped below the thresholds normally used to diagnose the disorder, including in patients with severe disease, showing how a sample collected at the wrong time could wrongly appear reassuring.

The abnormal bursts were especially pronounced in patients whose condition originated in a single adrenal gland rather than both. That distinction matters because disease confined to one gland can sometimes be treated by surgically removing it — and after the affected gland was removed in these patients, the unusual hormone bursts disappeared.