Nocturnal hypertension is elevated blood pressure that occurs at night. Normally, blood pressure varies by circadian rhythm and is 10–20% lower at night. This phenomenon is known as “nocturnal dipping.” The absence of the normal dipping pattern and high blood pressure at night have both been linked to complications like kidney damage and cardiovascular disease.
Read on to learn about nocturnal hypertension and its symptoms, causes, and management.
Nocturnal Hypertension Definition
Daytime blood pressure higher than 120/80 mmHg (millimeters of mercury, a measurement unit of pressure) is considered elevated. Nighttime blood pressure is typically lower than daytime. Nocturnal hypertension refers to any blood pressure above 110/65 mmHg at night.
Patterns of Nocturnal Blood Pressure
Nocturnal blood pressure can also be described by patterns of blood pressure changes throughout a 24-hour cycle:
- “Dipper” is the term for the normal 10–20% decrease in blood pressure that occurs overnight
- “Extreme-dipper” is a term when blood pressure drops more than the normal 20% at night
- “Non-dipper” is an abnormal situation in which blood pressure does not decrease as much as it should at night
- “Riser” and “reverse dipper” are terms to describe an increase in blood pressure at night
Non-dipping is common in those with high blood pressure. In one large study, non-dipping patterns were seen in 32–46% of people with hypertension, and reverse-dipping patterns were seen in 5–19%. Normal dipping patterns were seen in 27–54%.
If you have high blood pressure, these statistics should be of interest: There is a 50/50 chance that you may not have the normal nighttime lowering of blood pressure, which can add to your risk of complications.
Nocturnal Hypertension Symptoms
High blood pressure does not usually present with symptoms, so it’s commonly referred to as a “silent killer.” This is also true of nocturnal hypertension. Symptoms of nocturnal hypertension include:
- Frequent arousal from sleep at night
- Snoring, breath holding, and gasping at night (which the patient’s bed partner may describe)
- Frequent awakening to urinate at night (known as nocturia)
Nocturnal Hypertension Causes and Risk Factors
Nocturnal hypertension has many causes and risk factors. Scientists are actively researching this topic, attempting to discern what may truly cause nocturnal hypertension versus conditions that are just associated with nocturnal hypertension.
The following is a list of potential causes/risk factors for nocturnal hypertension:
Complications of Nocturnal Hypertension
Nocturnal hypertension shares many of the complications of high blood pressure in general and has been associated with the following:
- Kidney failure
- Kidney disease
- Heart attack
- Cardiovascular death
- Cognitive decline
- Heart failure
Nocturnal Hypertension Diagnosis
High blood pressure at night can be tough to diagnose because a normal blood pressure screening by your healthcare provider won’t cover it. Diagnosing nocturnal hypertension requires measuring blood pressure at night. However, waking up to check your own blood pressure would give you waking blood pressure readings and not reflect accurate nocturnal blood pressure.
The best way to measure nighttime blood pressure is through ambulatory blood pressure monitoring (ABPM). With ABPM, a blood pressure cuff worn for at least 24 hours intermittently checks blood pressure every 15 minutes to an hour. This generates a report that provides average blood pressure and the 24-hour blood pressure pattern.
Treatment of Nocturnal Hypertension
Nocturnal hypertension treatment is similar to high blood pressure treatment in general, including lifestyle considerations and medication. The timing of blood pressure medication is important. Some conditions that cause nocturnal hypertension warrant specific treatments.
Many of our lifestyle choices and habits can affect blood pressure. If you have elevated blood pressure, the following adjustments are recommended:
- Decrease salt intake
- Increase potassium intake
- Ensure adequate, good-quality sleep
- Get regular physical activity
- Maintain a healthy weight
- Quit smoking and avoid secondhand smoke
- If you drink alcohol, limit yourself to one drink per day (for women) or two drinks per day (for men)
- Ensure the treatment of underlying conditions including obstructive sleep apnea and diabetes
When it comes to treating high blood pressure, there are many medications available. Once-a-day pills are a convenient option that can be easier to remember to take. However, once-a-day blood pressure medications may not last a full 24 hours and can result in untreated high blood pressure at night.
One tactic to prevent this is to simply take one or more of your blood pressure medications at night. This is referred to as “chronotherapy,” and studies have shown that people who take blood pressure medication at night have better control of their blood pressure throughout the 24-hour period, including at night. Some studies have even suggested this leads to a lower risk of high blood pressure complications.
If you are on medication for high blood pressure and are concerned that you have high nighttime blood pressure, speak with your healthcare provider about the possibility of taking one or more of your medications at night instead of in the morning. Note that diuretics are typically not a good choice of medication to take at night because they will cause you to urinate more frequently at night.
Treatment of Underlying Causes
Treating and managing underlying causes and risk factors for nocturnal hypertension are also important. Those with symptoms of sleep apnea should see a sleep specialist for diagnosis and make sure to stick to treatment (such as continuous positive airway pressure or CPAP) if prescribed.
Limiting nighttime disturbance and setting aside time for adequate sleep is another essential aspect of treating nocturnal hypertension. Those with insomnia may benefit from treatments like melatonin or prescription medications if sleep hygiene efforts have failed.
When it comes to blood pressure, having a daytime blood pressure reading that is at goal once a year at your healthcare provider’s office doesn’t tell the whole story, especially if you are still treated for high blood pressure. Nocturnal hypertension or a lack of the typical blood pressure dip that should occur at night can increase the risk of serious complications. There are many potential causes and associated conditions, the most common of which are sleep apnea, diabetes, and kidney disease.
Diagnosis is achieved with ambulatory blood pressure monitoring, which requires wearing an automated blood pressure cuff that checks blood pressure intermittently throughout the day and night. Treatment includes many of the lifestyle considerations and medications that treat high blood pressure in general, with special consideration for the timing of blood pressure medication. Ensuring adequate, good-quality sleep is essential.
A Word From Verywell
It may be disheartening to hear about all the ways high blood pressure can be lurking and the risks it poses. Know that there are actionable things you can do to lower your blood pressure. Seeing a healthcare provider for regular follow-ups, setting your own detailed plan for achieving lifestyle goals, and adhering to medications are effective ways to feel and have better control of your health.
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