[Circadian rhythm of melatonin and blood pressure changes in patients with essential hypertension]
Related Experiment Video
Updated: Jun 27, 2026

Through-the-Wall Blood Sampling Method to Minimize Sleep Disruption in Clinical Settings
Published on: June 13, 2025
Hong-Wei Cui1, Zhong-Xia Zhang, Ming-Tong Gao
1Department of Emergency, Hospital of Weifang Medical University, Weifang 261031, China. cuihongwei62@126.com
Objective:
To observe the association between melatonin (MLT) secretion and blood pressure changes during 24 hours in hypertensive patients (HPT) with (dipping) or without (non-dipping) night time blood pressure reduction.
Methods:
The 24-hour blood pressure and urine 6-SMT (6-sulfatoxymelatonin, metabolism product of MLT in urine) in the daytime and nighttime were measured in normal control subjects (n = 20), non-dipping HPT group (n = 32) and dipping HPT group (n = 36).
Results:
As expected, blood pressure reduction during the night was significantly lower in non-dipping HPT group compared to control and dipping HPT groups. Nighttime 6-SMT was significantly higher than daytime 6-SMT in all groups and nighttime urine 6-SMT levels and ratio of nighttime/daytime urine 6-SMT levels were significantly lower in non-dipping HPT group compared to control and dipping HPT groups (all P < 0.01). Moreover, ratio of nighttime/daytime urine 6-SMT levels are positively correlated blood pressure reduction during nighttime (P < 0.05) in all groups.
Conclusions:
Circadian rhythm of MLT secretion is maintained but nighttime MLT secretion was significantly reduced and related to disorders of circadian rhythm of blood pressure in non-dipping HPT group.
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