Nighttime blood pressure can provide insights into a person’s health

Scientists from the University of Waterloo attempted to understand why some people do not experience a normal drop in blood pressure during sleep. The researchers hypothesized that the cause might be related to a disruption in the coordination of circadian rhythms in various body systems that are involved in blood pressure regulation.

To study this issue, the team led by Professor Anita Leighton used a computer model of the human body. It includes several key mechanisms for controlling blood pressure: the kidneys’ function in excreting sodium, vascular tone, the activity of the nervous system, hormonal processes (including the renin‑angiotensin‑aldosterone system), as well as the influence of sleep–wake cycles. The advantage of the model is that it allows you to change the parameters of individual systems one by one — this is difficult to do in real clinical or laboratory conditions.

During virtual experiments, scientists found that simply weakening the daily rhythm of kidney function has only a slight effect on the level of nighttime blood pressure. However, if this rhythm is shifted in time, even by a few hours relative to other systems, this is enough to turn a normal blood pressure profile into a pathological one, typical of “non‑dippers.” This effect became especially noticeable in people with high salt intake or increased sensitivity to it — factors that are already associated with an increased risk of high blood pressure.

The study is based on mathematical modeling, not on observations of real patients. Therefore, it does not provide ready‑made recommendations for changing habits, for example, regarding the timing of consuming salty foods or taking blood pressure medications. Its main value lies in the fact that it points to a possible mechanism underlying the development of nocturnal blood pressure elevation: the desynchronization of biological rhythms. This hypothesis can now be tested in experimental and clinical studies. In the future, understanding this mechanism may help to more accurately identify the causes of nocturnal hypertension and to select more effective approaches to its treatment.

At the same time, the model used parameters corresponding to the female body, while details such as the exact timing of meals, the level of physical activity, or individual sleep stages were not taken into account separately.

If a person’s 24‑hour blood pressure monitoring reveals a “non‑dipping” type, it is important to discuss this with their attending physician. The specialist will assess it in combination with other health indicators and, if necessary, suggest additional examinations.