From the Guidelines
Non-dipper hypertension is a condition where blood pressure fails to decrease by the expected amount during sleep at night, and it is associated with increased risk of cardiovascular complications. This condition is characterized by the absence of a natural "dipping" in blood pressure that occurs during sleep in normal individuals. The diagnosis of non-dipper hypertension is typically made through ambulatory blood pressure monitoring (ABPM), which measures blood pressure at regular intervals over a 24-hour period 1. Several factors can contribute to non-dipper status, including sleep apnea, chronic kidney disease, autonomic dysfunction, high salt intake, and certain medications. Key points to consider in non-dipper hypertension include:
- The condition is associated with increased risk of cardiovascular complications, including heart attack, stroke, and kidney damage, compared to those with normal dipping patterns 1
- Treatment typically involves optimizing antihypertensive medication timing, with some medications being more effective when taken at bedtime rather than in the morning
- Lifestyle modifications are also important, including salt restriction, regular physical activity, weight management, and addressing sleep disorders
- The underlying physiological mechanism involves disruption of the circadian rhythm of blood pressure regulation, often related to increased sympathetic nervous system activity during the night or impaired sodium excretion. It is essential to note that the most recent guidelines, such as the 2020 U.S. Department of Veterans Affairs/U.S. Department of Defense clinical practice guideline, emphasize the importance of early detection and management of hypertension to reduce the risk of cardiovascular complications 1.
From the Research
Definition of Non-Dipper Hypertension
- Non-dipper hypertension refers to a condition where an individual's blood pressure does not dip or decrease by at least 10% at night, unlike the normal dipping pattern observed in most people 2.
- This condition is characterized by a nighttime blood pressure that is not significantly lower than the daytime blood pressure.
Characteristics of Non-Dipper Hypertension
- Non-dipper hypertension is often associated with a greater risk of target organ damage among individuals with essential hypertension 2, 3.
- Advanced age, African-American ethnicity, female sex, postmenopausal status, sodium sensitivity, sleep apnea, sleep quality, anger, hostility, depression, stress, social support, and socioeconomic status have been linked to non-dipping blood pressure patterns 2.
Comparison with Dipper Hypertension
- Dipper hypertension is characterized by a nighttime blood pressure that is 10-20% lower than the daytime blood pressure 2.
- Non-dippers have worsened cardiovascular outcomes than dippers, and ambulatory blood pressure monitoring with a lack of nocturnal BP fall has been shown to be more closely associated with target organ damage and worsened cardiovascular outcome than in patients with essential hypertension with dipping pattern 3.
Underlying Mechanisms
- The underlying pathogenetic mechanisms potentially linking non-dipping with cardiovascular disease are not fully understood, but extrinsic and intrinsic factors including abnormal neurohormonal regulation, lack of physical activity, nutritional factors such as increased dietary sodium intake, and smoking of tobacco have been implicated for blunted circadian rhythm of BP 3.
- Certain diseases such as diabetes and chronic renal diseases also affect the circadian BP rhythm 3.