Hypertension Disrupts Natural Blood Pressure ‘Dipping’ Rhythm in Both Sexes

Newswise — Rockville, Md. (September 11, 2024)—High blood pressure disrupts natural day-and-night blood pressure dipping patterns in males and females, according to a new study from Tulane University School of Medicine. The findings are published in the American Journal of Physiology-Heart and Circulatory Physiology. The article has been chosen as an APSselect article for September.   

Nighttime blood pressure normally dips 10% to 20% below daytime levels. Physical activity and stress may reduce the reliability of daytime blood pressure measurements. Nondipping—when blood pressure stays at daytime levels—is a serious ailment linked to an increased risk of cardiovascular diseases and organ damage. However, the mechanism behind nondipping is not fully explained. 

Researchers from the Lindsey Lab at Tulane used an implantable, continuous monitoring method called radiotelemetry to determine how hypertension in male and female mice changed their blood pressure during the day and night. The researchers continuously measured the animals’ blood pressure to learn how much it decreases during sleep. 

Physiologists also collected blood vessel samples from the mice at various times of the day and night to examine how clock genes and estrogen receptors work together to regulate blood pressure. This was done using a highly accurate technique called droplet digital PCR. Additionally, the team studied how these vessels responded to drugs that caused them to dilate or constrict. 

High blood pressure induced by high salt consumption, aging and poor sleep quality, among other factors, can lead to nondipping. This study also confirmed for the first time that estrogen receptors follow a daily cycle that aligns in the vessels with changes in a specific class of clock genes called period genes. This gene plays a key role in regulating the circadian rhythm. In addition, this study shows high blood pressure affects blood pressure rhythms. The expression of clock genes and estrogen receptors in the blood vessels is similar in both sexes.

“By understanding these changes, we can create better treatments that work specifically for men and women at different times of the day, which is a practice called ‘chronotherapy’,” said Bruna Visniauskas, PhD, lead study author and instructor at Tulane. “This research could help us develop new strategies to lower the risk of high blood pressure and disruptions in daily rhythms in both sexes.”

Read the full article, “Hypertension disrupts the vascular clock in both sexes.” It is highlighted as one of this month’s “best of the best” as part of the American Physiological Society’s APSselect program. Read all of this month’s selected research articles.  

NOTE TO JOURNALISTS: To schedule an interview with a member of the research team, please contact APS Media Relations or call 301.634.7314. Find more research highlights in our Newsroom.  

Physiology is a broad area of scientific inquiry that focuses on how molecules, cells, tissues and organs function in health and disease. The American Physiological Society connects a global, multidisciplinary community of more than 10,000 biomedical scientists and educators as part of its mission to advance scientific discovery, understand life and improve health. The Society drives collaboration and spotlights scientific discoveries through its 16 scholarly journals and programming that support researchers and educators in their work.