Hypertension is a common chronic disease. The purpose of prevention and treatment of hypertension is to reduce damage to target organs such as the heart, brain, blood vessels, and kidneys. Studies have shown that the degree of damage to target organs is not only related to the magnitude of blood pressure elevation, but also to the type and fluctuation of hypertension. Elevated blood pressure at night is associated with a higher risk of cardiovascular events and more severe damage to target organs. Therefore, it is necessary and important to manage blood pressure at night.
The normal blood pressure change has a circadian rhythm, showing a double peak and a valley. The first peak occurs between 6 am and 10 am. The second peak occurs between 16:00 and 20:00 in the afternoon. At around 0:00 at night, blood pressure troughs. This blood pressure change is called dipper blood pressure. If the drop in nighttime blood pressure is less than 10% of daytime blood pressure, it is called non-dipping blood pressure. Nocturnal blood pressure drops too much, more than 20% of daytime blood pressure, called deep dip blood pressure. Nighttime blood pressure is higher than daytime blood pressure, called reverse dipper blood pressure. Non-spoon type, deep spoon type, and reverse spoon type are all abnormal blood pressure rhythms.
Recently, a team from Oxford University published a study. By comparing blood pressure levels of 21,739 hospitalized patients and the community population. RESULTS: Among hospitalized patients, 48.9% had nocturnal BP elevation, with a mean diurnal systolic BP difference of 8 mmHg, while in the community population, 10.8% had nocturnal BP elevation, with an average diurnal systolic BP difference of 8.5 mmHg. Blood pressure in these people was characterized by lower systolic blood pressure during the day and higher systolic blood pressure at night. Studies conducted by Chinese scholars have shown that the incidence of non-dipper blood pressure in hypertensive hospitalized patients is 60.2%, and the damage to target organs is more serious. Therefore, only measuring blood pressure during the day may result in missed diagnosis of hypertensive patients, or it may be difficult to detect serious blood pressure fluctuations. Only by strengthening nighttime blood pressure monitoring and measuring ambulatory blood pressure can the damage of target organs be reduced.
In order to better manage the risk of nocturnal blood pressure, Italian scholars, in 2014, published a paper in the journal “Hypertension”, proposing the idea of paying attention to nocturnal blood pressure variability BPV . BPV refers to the standard deviation SD of nocturnal ambulatory blood pressure. The study showed that a 10 mmHg standard deviation increase in systolic blood pressure BPV was associated with a 1.48-fold increased risk of cardiovascular events. A 10 mmHg increase in the standard deviation of diastolic blood pressure BPV was associated with a 3.34-fold increase in the risk of cardiovascular death. The study also found that factors such as sleep apnea may contribute to increased nighttime blood pressure variability.
At present, the academic community believes that the pathogenesis of nocturnal hypertension mainly includes abnormal autonomic regulation and changes in angiotensin levels. Nocturnal blood pressure variability is mainly affected by three factors. The first is insulin resistance. The second is sleep apnea hypopnea syndrome. The third is the lack of melatonin secretion. Therefore, hypertensive patients with diabetes, sleep snoring, and insomnia need ambulatory blood pressure monitoring to detect nighttime blood pressure variability in time.
It should be noted that chronic kidney disease can lead to the uncontrolled mechanism of the kidney to regulate blood pressure and its rhythm, which is an important pathological basis for hypertension and abnormal blood pressure rhythm. Studies have shown that the incidence of non-dipper blood pressure in patients with stage 1 chronic kidney disease is about 45%, while the incidence of non-dip blood pressure in patients with stage 5 chronic kidney disease is as high as 80%. This blood pressure change can cause persistent impairment of cardiac and vascular endothelial cell function, trigger inflammatory responses and disorders of coagulation mechanisms, promote the progression of chronic kidney disease, and at the same time, increase the risk of cardiovascular disease.
Prevention and treatment of nighttime blood pressure variability requires measures to address the cause, such as controlling blood sugar within the target range, timely treatment of sleep apnea, and resolving insomnia. Also, manage your daily life. For example, studies have found that saltPatients with increased intake or salt-sensitive hypertension had greater fluctuations in nocturnal blood pressure, especially in patients with reverse dip-type hypertension. Therefore, it is necessary to limit the intake of salt. For another example, Turkish scholars found that eating a meal 2 hours before bedtime would disrupt blood pressure rhythm, resulting in a higher level of blood pressure at night. Reasonable selection of drugs is an important measure to deal with nocturnal hypertension. Taking drugs before going to bed and choosing long-acting drugs can help to control nocturnal blood pressure variability.
To whomever you love, pass on your health.