Wearable monitoring exposes a missed hormonal pattern in hypertension
A wearable device has pulled back the curtain on a form of primary aldosteronism that routine blood tests can miss. The disorder, a treatable and sometimes curable cause of high blood pressure, may affect up to one in five people with hypertension, yet many patients never receive a diagnosis because the hormone signal is not steady from hour to hour.
The new work centers on a simple but clinically disruptive observation: aldosterone does not always sit at a fixed elevated level. In many patients, it rises in bursts, and some of those surges occur during sleep, when standard blood sampling is almost never performed. A single blood draw can therefore capture a quiet interval and falsely reassure clinicians that the endocrine system is behaving normally.
Nighttime hormone bursts were captured at home, not in a ward
Investigators used a portable sampling system developed at the University of Bristol to measure hormones every 20 minutes over a 24-hour period while participants lived normally at home. The device, described as about the size of a mobile phone and worn at the waist, allowed people to sleep, move, and go through ordinary daily activity while hormone data were collected continuously from the skin.
The proof-of-concept study included 60 patients across Bristol, Bergen, Stockholm, and Athens. That design matters because endocrine disorders often change in real-world settings, where stress, posture, sleep, meals, and circadian biology shape secretion patterns. Hospital-based testing can flatten those rhythms and obscure the very abnormality clinicians are trying to detect.
Dr. Thomas Upton described primary aldosteronism as an important cause of high blood pressure and the most common cause of secondary hypertension seen in the blood pressure clinic. He also pointed to a core diagnostic problem: hormone levels fluctuate across the day, and the complexity of the workup means diagnosis is often delayed or never made.
The wearable approach changes the frame entirely. Rather than asking whether aldosterone is high at one random moment, it asks whether the adrenal glands are producing abnormal rhythms over time. In this study, the answer was yes.
Aldosterone fell below usual cutoffs even in severe disease
Computational analysis of the hormone profiles showed repeated nighttime bursts of aldosterone, while the overall day-night rhythm remained intact. The pattern was not limited to aldosterone alone. Researchers also tracked 18-hydroxycortisol and 18-oxocortisol, two closely related hormones that helped clarify the steroid signature of the disorder.
The most clinically important finding is blunt: current diagnostic thresholds can miss disease because aldosterone does not remain consistently elevated. Even in some severe cases, levels dipped below the minimum values commonly used to flag primary aldosteronism. If testing lands during one of those troughs, the result can look deceptively ordinary.
The bursts originated from the adrenal glands and were especially pronounced in patients whose disease stemmed from a problem in only one adrenal gland. In those cases, the abnormal pattern disappeared after surgical removal of the affected gland. That before-and-after reversal strengthens the link between the hormone rhythm and the underlying adrenal lesion, rather than a nonspecific fluctuation in blood pressure or stress response.
The biology is straightforward enough to matter at the bedside. Aldosterone increases salt and water retention, expands circulating volume, and pushes blood pressure upward. When secretion becomes erratic, standard screening based on a single time point loses sensitivity. A patient with genuine disease may therefore move through years of uncontrolled hypertension, accumulating avoidable cardiovascular risk while screening results remain ambiguous or negative.
A shift from single blood draws to rhythm-based diagnosis
Prof. Stafford Lightman said the findings suggest clinicians may need to rethink how they search for the disorder, especially since Endocrine Society guidance already recommends considering primary aldosteronism in all people with hypertension. The implication is not merely technical. It points to a different diagnostic philosophy: one that values hormone dynamics, especially overnight patterns, over isolated laboratory snapshots.
Dr. Eder Zavala described the 24-hour monitoring as a way to reveal a previously hidden pattern of nocturnal hormone bursts and argued that more detailed mathematical and computational analysis of daily hormonal profiles may help uncover earlier and subtler forms of disease. That approach could matter most for patients who currently fall into a gray zone, where suspicion remains high but standard tests are inconsistent or unrevealing.
For cardiology and hypertension clinics, the practical consequence is hard to ignore. Primary aldosteronism is not just another cause of elevated blood pressure; it is one of the few secondary causes that can be directly treated, and in selected patients surgery can eliminate the source. Earlier detection could reduce downstream heart disease, stroke, and other complications tied to long-standing uncontrolled hypertension.
The study also raises a broader point about endocrine diagnostics. Many hormone disorders are built on pulsatility, circadian variation, and context dependence. When clinicians measure only one slice of that biology, they risk missing the disorder entirely. Continuous or repeated outpatient monitoring offers a more faithful view of physiology and may be especially useful when symptoms are nonspecific but consequences are severe.
For now, the data remain proof-of-concept rather than a finished clinical pathway. Larger studies will need to define how dynamic hormone measurement fits into routine hypertension workups, which patients should be tested first, and how to translate complex rhythm data into a usable diagnostic algorithm. The central problem, though, is already plain: a disorder that can be curable may continue to hide if medicine keeps looking only at one blood sample at a time.