A wearable sensor that samples hormones through the skin every 20 minutes has revealed nighttime hormone surges in people with a common, frequently overlooked cause of high blood pressure, according to a study published in Science Translational Medicine. The findings suggest that standard single-point blood tests may be missing a hormonal pattern that only shows up while patients sleep.
The condition, primary aldosteronism, occurs when the adrenal glands overproduce the hormone aldosterone, driving up blood pressure independent of the more familiar renin-angiotensin pathway that most hypertension drugs target. Researchers say it accounts for a meaningful share of secondary hypertension cases, though the condition is widely considered underdiagnosed because routine screening captures only a single blood draw, typically taken during the day.
Catching what daytime tests miss
Led by researchers at the University of Bristol and the University of Bergen, with collaborators in Manchester, Stockholm and Athens, the team fitted 60 participants across the four cities with a device called U-RHYTHM, a phone-sized wearable, developed at Bristol, that draws hormone samples through the skin around the clock while people go about normal daily activities. The device showed that some patients experienced aldosterone bursts overnight, during hours when clinics rarely draw blood, and that hormone levels in a few severe cases dipped below standard diagnostic thresholds at other points in the day, a pattern that could cause the disorder to be missed or misdiagnosed. In patients whose overproduction traced to a single affected adrenal gland, the nighttime spikes disappeared after that gland was surgically removed, reinforcing the link between the bursts and the disease.
"Primary aldosteronism is an important cause of high blood pressure and the most common cause of secondary hypertension we see in our blood pressure clinic."
— Dr. Thomas Upton, University of Bristol
The authors, including lead researcher Marianne Grytaas and senior investigators Eder Zavala and Stafford Lightman, say the results point toward diagnosing the condition by tracking hormone rhythms over a full day rather than relying on a single snapshot. But they and outside specialists caution the work is a proof-of-concept study in a modest cohort of 60 people rather than a validated diagnostic tool: it has not been tested against standard-of-care screening in a large, independent population, and a wearable-based diagnostic pathway would need regulatory clearance and broader trials before reaching clinics. The research was funded by the European Union's Horizon 2020 program along with the UK's Medical Research Council, UKRI-BBSRC and several other European research bodies.
If confirmed in larger studies, more sensitive detection could matter because primary aldosteronism carries a higher risk of heart attack, stroke and kidney damage than blood-pressure elevation from other causes at a similar level, and it often responds to different treatment, either surgery or a class of drugs called mineralocorticoid receptor antagonists, than standard blood pressure medication. The Bristol team says it is now working to miniaturize the sensor further and test it in larger, more diverse patient groups.
