This article has been written and medically reviewed by Dr. Darshan Shingala (M.D, MPH) – a qualified and practicing medical doctor – for maximum factual accuracy and reliability.
If you suffer from high or low blood pressure, then you may be wondering how your sleep can affect these conditions.
Lack of sleep, sleeping longer than 9 hours, and sleeping on your back can potentially raise your blood pressure; which in turn, can increase your risk of stroke, heart failure, cardiomyopathy, arrhythmias, and coronary artery diseases like angina.
In the rest of this article, I have drawn upon my medical knowledge to explain in more detail how sleep affects blood pressure and what you can do to stay healthy.
8 Ways Sleep Affects Blood Pressure
Below I’ve listed 8 ways that sleep and sleep disorders can affect blood pressure, and the potential resulting health consequences:
1: High Nocturnal Blood Pressure Increases Cardiovascular Risk
Several clinical studies show that diminished nocturnal dipping of blood pressure during sleep is a strong independent predictor of increased cardiovascular risk.
In other words, if your blood pressure while sleeping is not lower than your daytime blood pressure readings, then you may be at a higher risk of developing various cardiovascular disorders.
These include hypertension, stroke, heart failure, cardiomyopathy, arrhythmias, and coronary artery diseases, like angina and myocardial infarction [2, 3, 4].
The Ohasama Study reported that if there is up to a 5% decline in the normal nocturnal dipping of blood pressure, then there is approximately a 20% higher risk of mortality associated with cardiovascular factors [5, 6].
In addition to cardiovascular disorders, the risk for developing other associated diseases, such as chronic kidney disease, diabetes, and obstructive sleep apnea, may also increase substantially if diminished dipping of nocturnal blood pressure remains unresolved for a long period of time.
2: Insufficient Sleep Can Cause High Blood Pressure
If you are middle-aged, and you have a habitual short sleep duration, you may be at an increased risk of developing hypertensive heart disease, also referred to as hypertension.
Hypertension is a medical condition in which the blood vessels have persistently high pressure, which lies beyond the normal range.
The normal range for blood pressure is defined as a systolic blood pressure of 120 mm Hg, and a diastolic blood pressure of 80 mm Hg.
Studies show that shorter sleep duration on a regular basis, especially when exhibiting a habitual pattern, may disrupt the circadian rhythm of the body, increase adiposity, cause metabolic dysfunction, and increase hormonal imbalances [3, 4].
Chronically, these changes can disturb the autonomic balance of the body, and lead to disruptive changes in the blood pressure, as well.
A study found that people who sleep less than 4 hours every night tend to be at a higher risk of developing hypertension, when compared to people who obtain at least 7 hours of sleep each night .
The National Sleep Foundation reported in 2002 that people who suffer from prolonged sleep deprivation are more likely to be stressed out, easily irritable, and pessimistic.
These negative emotional states make it more difficult for sleep-deprived people to maintain a healthy diet and exercise regimen, which are essential for protection against hypertension .
3: Sleeping More Than 9 Hours Can Cause High Blood Pressure
The Sleep Heart Health Study found that a long sleep duration, defined as more than 9 hours of sleep every night, is associated with prevalent hypertension.
In other words, this study suggests that people who obtain more than 9 hours of sleep each night are more likely to develop hypertensive heart disease, in comparison to people who sleep for the recommended duration of 7 to 8 hours .
It has been observed from several studies that long sleep duration is also associated with reduced nocturnal dipping, and morning surge of blood pressure [8, 9].
As mentioned earlier, it is interesting that habitual short sleep duration is also a risk factor for developing high blood pressure .
We can infer from these scientific findings that neither short sleep duration, nor long sleep duration, are beneficial for patients who are at risk of developing hypertension.
I would, therefore, suggest that you adhere to the recommended sleep duration of 7 to 8 hours every night, in order to better regulate your daytime and nocturnal blood pressure.
4: Insomnia Can Increase the Risk of Hypertension
A study with 8,757 participants was conducted over a period of 6 years.
It found that participants who reported symptoms of insomnia at baseline, such as difficulty falling asleep, and trouble staying asleep throughout the night, had an increased risk of hypertension at follow-up.
The rationale behind the possible link between insomnia and hypertension is that insomnia tends to activate the hypothalamic-pituitary-adrenal axis, and the sympathetic nervous system.
These are well-known predisposing factors for the development of hypertensive disease.
It is hypothesized that insomnia may be associated with chronic secretion of cortisol, also known as the stress hormone.
Increased cortisol levels may further lead to hyperarousal, increased alertness, and hypertension.
People with insomnia can have a 3-fold increased risk of developing high blood pressure, in comparison to normal sleepers [9, 10, 11].
If you are experiencing symptoms of insomnia, I recommend that you seek medical help, and address your sleep problems, as advised by your doctor.
5: Certain Medical Conditions Can Cause Low Blood Pressure
There are many medical conditions that can lead to the lowering of blood pressure to less than 120/80 mm Hg, which is known as the hypotensive state.
Even hypotension can be dangerous if the blood pressure reading is below 90 mm Hg systolic, and 60 mm Hg diastolic.
Sleep disorders and circulatory disorders, including hypotension, are interlinked, and may influence each other [1, 6].
The following conditions can lead to both sleep related problems, and hypotension, in some people:
Some people experience lowering of blood pressure one to two hours after eating.
This condition is referred to as postprandial hypotension, and it affects mostly older adults, or people with disorders of the autonomic nervous system, such as Parkinson’s disease.
It is not uncommon to experience symptoms of postprandial hypotension at night after dinner, which can further interfere with one’s sleep.
The mechanism behind postprandial hypotension is hypothesized to be the failure of the normal digestive and circulatory processes that occur in the body while eating.
If you are experiencing symptoms of postprandial hypotension, like dizziness, faintness, and falls, then I would recommend that you eat frequent small portions throughout the day, and drink plenty of water.
You may also consider eating low-carb meals, and limiting the consumption of alcohol, to help reduce the troublesome symptoms [1, 9].
Several endocrine disorders can potentially trigger low blood pressure.
These include parathyroid disease, Addison’s disease (which is characterized by adrenal insufficiency), and hypoglycemia (which is characterized by low blood sugar).
If these disorders are left untreated, they can lead to severe hormonal imbalances, which can further disrupt the sleep cycle [1, 9].
Since sleep is greatly influenced by the nutritional status of the body, I recommend maintaining a healthy diet and lifestyle.
For instance, a deficiency of vitamin B-12, vitamin B-9, and iron can lower the production of red blood cells, leading to anemia and hypotension.
In addition to dietary nutrients, blood pressure is influenced by daily intake of water.
If you are dehydrated, you may experience signs of weakness, such as dizziness, fatigue, lethargy, and hypotension.
Uncorrected deficiencies and dehydration can lead to metabolic dysfunction, blood pressure fluctuations, and disturbance of sleep [1, 9].
Certain medications can cause lowering of blood pressure, especially when consumed before going to bed [1, 9].
These include diuretics (furosemide, hydrochlorothiazide), alpha blockers (prazosin), beta blockers (atenolol, propranolol), and tricyclic antidepressants (doxepin, imipramine).
6: Sleeping Habits Can Influence Blood Pressure
Blood pressure tends to vary throughout the day; depending on the time of the day, position of the body, rhythm of breathing, physical condition, medications, dietary habits, and stress levels.
As we know, every individual demonstrates short-term blood pressure variability during the day; like a morning surge, and physical and psychological stress-induced daytime fluctuations in blood pressure.
Similarly, each person also demonstrates short-term blood pressure variability at night, even while sleeping.
Examples are night-time surges triggered by episodes of obstructive sleep apnea, blood pressure alterations during the rapid-eye-movement phase of the sleep cycle, and blood pressure fluctuations while exhibiting certain nocturnal behaviors, such as arousal and nocturia.
If you are seeking to regulate these short-term blood pressure variabilities, I would advise you to approach your doctor for a detailed diagnosis of the underlying medical condition, which may be causing these fluctuations to occur in your blood pressure [6, 9].
7: The Back-Sleeping Position Can Raise Blood Pressure
We know from scientific literature that half of all patients with hypertension have obstructive sleep apnea, and the majority of patients with obstructive sleep apnea have breathing problems associated with the supine sleeping position .
It seems that body position – especially while sleeping – may substantially influence the incidence and severity of sleep-related breathing abnormalities, such as those experienced by obstructive sleep apnea patients.
A few relatively new studies suggest that avoiding the supine position during sleep could become an alternative non-pharmacological treatment for many patients with hypertensive heart disease and obstructive sleep apnea.
A study found that avoiding the supine position while sleeping can lead to a reduction in 24-hour mean systolic/diastolic blood pressure by 6.4/2.9 mm Hg, mean awake systolic/diastolic blood pressure by 6.6/3.3 mm Hg, and the mean sleeping systolic/diastolic blood pressure by 6.5/2.7 mm Hg .
If you are considering avoiding sleeping in a supine position, you should opt to sleep on your left side, as this can help to relieve the pressure by the phenomenon of compression of blood vessels.
If you are pregnant, sleeping on your left side can be highly beneficial, especially if you are concerned about developing high blood pressure associated with gestation.
8: Good Sleep Hygiene Can Prevent Blood Pressure Changes
Studies show that if you are nervous or anxious prior to going to bed, it can cause undesirable changes in your blood pressure .
Therefore, it is essential that you implement good sleep hygiene practices, in order to maximize your overall wellbeing, and prevent lifestyle diseases, including hypertensive heart disease.
I would strongly advise you to minimize all types of distractions closer to bedtime, so that you can fall asleep quickly, and get an uninterrupted and sound night’s sleep.
I usually tell my patients to sleep in a calm environment; avoid excessively bright, flashy, and flickering lights in the bedroom; limit screen time, and avoid using electronic devices prior to going to bed.
The implementation of these sleeping practices often helps people to unwind, relax, and recalibrate their blood pressure.
Maintain a Silent and Calm Environment in the Bedroom
It can be quite challenging and unhealthy to fall asleep in a noisy environment, as loud sounds lead to unnecessary neural stimulation, which can negatively impact your blood pressure, and prevent you from falling asleep.
On the other hand, a quiet sleeping environment can help relieve stress, calm your mind, and boost your overall health.
Thus, I would recommend that you try to maintain a silent and calm atmosphere in your bedroom, especially before going to bed, so that you can prevent triggering any undesirable fluctuations in your blood pressure at nighttime.
Avoid Bright, Flashy, Flickering Lights in the Bedroom
The presence of excessively bright, flashy, or flickering lights in your bedroom can lead to unwanted sleep disruptions by altering your sleep/wake cycle.
I would suggest that you dim your bedroom lights a few hours prior to bedtime, and ensure that your bedroom lights do not flicker unnecessarily, because flickering lights tend to trigger headaches and blood pressure changes in some people.
Limit Screen Time and Electronic Device Use Closer to Bedtime
It is a well-known fact that the blue light emitted from screens and electronic devices can disturb the circadian rhythm by altering the sleep/wake cycle.
I would suggest that you limit the use of electronic devices, such as mobile phones, laptops, tablets, and television, especially before going to bed.
I would recommend that you try to observe a period of no screen time for up to 2 to 3 hours before bedtime.
This will help you improve the quality of your sleep, reduce the frequency of nightmares, and recalibrate your circadian rhythm and blood pressure.
Maintain a Blood Pressure Diary and Seek Medical Help
If you continue to struggle with sleeping problems, and have difficulty managing your blood pressure, I strongly recommend that you schedule a visit with your primary care physician at the earliest possible time.
It is a good idea to listen to your body, be attentive, and take notes if you experience any strange or adverse symptoms.
I usually advise my patients to maintain a blood pressure diary, if possible, and record their blood pressure frequently throughout the day, at regular time intervals.
A blood pressure diary can help your doctor to have a better understanding of your concerns, and thereby assist them in arriving at an accurate diagnosis.
I would also encourage you to avoid procrastinating regarding your visits to the doctor, because sometimes delays or ignorance can lead to serious cases of missed diagnosis.
In general, our blood pressure tends to drop slightly when we sleep, due to a physiological phenomenon known as nocturnal dipping.
Our sleep cycle and vascular circulatory system are closely linked to each other by the hypothalamic-pituitary-adrenal axis, and the autonomic nervous system.
Any disturbances of the autonomic balance of the body may lead to disruptive changes in circadian rhythm, metabolism, hormonal regulation, and sleep cycle, which may result in blood pressure-related problems, such as hypertension and hypotension.
For instance, clinical studies show that diminished nocturnal dipping of blood pressure during sleep, habitual short sleep duration, sleep deprivation, insomnia, and long sleep duration are associated with an increased overall cardiovascular risk – including the risk of developing hypertension.
It is interesting to note that both short and long sleep duration are risk factors for developing high blood pressure.
Therefore, it is recommended that you adhere to the recommended sleep duration of 7 to 8 hours every night, in order to better regulate your circadian rhythm and blood pressure.
Practicing good sleep hygiene by minimizing distractions at bedtime can also help prevent undesirable changes in your blood pressure.
Studies show that different sleeping habits can influence short-term blood pressure variability.
For instance, sleeping position can influence the incidence and severity of obstructive sleep apnea and hypertensive heart disease.
Furthermore, the consumption of certain pharmacological drugs, or the presence of certain medical conditions, can also lead to sleep disturbances and low blood pressure.
Hence, it is recommended that you visit your primary care physician to seek timely medical help, and maintain a blood pressure diary to assist your doctor in arriving at an accurate diagnosis.
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This website does not provide medical advice – consult with your doctor for the best guidance.
Image Attribution and Licensing
Main image: ‘Measuring blood pressure’ by bialasiewicz (used with permission and commercially licensed through Envato Elements).
Dan is the founder and head content creator at Bedroom Style Reviews.
He has been working as a professional online product reviewer since 2015 and was inspired to start this website when he ended up sleeping on a memory foam mattress that was too soft and gave him backache.
Through in-depth research and analysis, Dan’s goal with this website is to help others avoid such pitfalls by creating the best online resource for helping you find your ideal mattress, bedding, and bedroom furniture.
Dan is a qualified NVQ Level 2 Fitness Instructor with 6 years’ experience helping clients improve their health through diet, exercise, and proper sleep hygiene.
He also holds several college and university-level qualifications in health sciences, psychology, mathematics, art, and digital media creation – which helps him to publish well researched and informative product reviews as well as articles on sleep, health, wellbeing, and home decor.
Dan also has direct personal experience with insomnia, anxiety, misophonia (hypersensitivity to sounds), and pain from both acute and long-standing sporting injuries – he enjoys writing insightful articles around these subjects to help fellow sufferers of such conditions.
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