Hypertension and Hypotension

March 2024 | Brian Chicoine, MD - Medical Director, Adult Down Syndrome Center

Key Points

The blood pressure of people with Down syndrome tends to be on the lower side.
High blood pressure (hypertension) is much less common in people with Down syndrome.
Blood pressures that are too low seem to be more common in people with Down syndrome.

General information

Blood pressure is recorded and reported as two numbers. The first or top number is the systolic blood pressure. This is the pressure of the blood pushing against the artery walls when the heart contracts. The second or bottom number is the diastolic blood pressure. This is the pressure of the blood pushing against the artery walls when the heart muscle is resting between contractions.

Blood pressure is measured with a sphygmomanometer, commonly called a blood pressure cuff. The measures are recorded in millimeters (mm) of mercury (Hg).

Normal, or ideal, blood pressure is between 90/60 and 120/80 mm Hg. High blood pressure (hypertension) occurs when someone’s blood pressure is consistently above 140/90. Low blood pressure (hypotension) is defined as blood pressures below 90/60. Abnormally low blood pressure occurs when someone has low blood pressure and has symptoms associated with low blood pressure.

Normal blood pressure is lower in children than in adults (with and without Down syndrome).

Symptoms

Low blood pressure

Common symptoms associated with low blood pressure include:

Dizziness
Unsteadiness of gait (walking)
Nausea
Blurred vision
Feeling weak
Confusion
Fainting (syncope)

High blood pressure

High blood pressure can cause:

Headaches
Chest pain
Dizziness
Difficulty breathing
Nausea
Vomiting
Blurred vision or other vision changes
Anxiety

Mildly or moderately elevated blood pressure

Mildly or moderately elevated blood pressure often has no symptoms; however, it if it left untreated, it is a risk factor for:

Congestive heart failure (inability of the heart to adequately pump blood)
Myocardial infarctions (heart attacks)
Strokes
Kidney disease
Damage to the blood vessels of the retina (back of the eye)

Issues in people with Down syndrome

Normal blood pressure in people with Down syndrome is typically in the lower part of the normal range. It is typically closer to 90/60 for people with Down syndrome. However, many people with Down syndrome often have a blood pressure below 90/60.

Even with blood pressures that are on the lower side of normal or even lower than normal, many people with Down syndrome don’t have symptoms associated with low blood pressures.

Typical blood pressure for each person with Down syndrome is unique to that individual. Similarly, the pressure that is “too low” and results in symptoms varies from person to person. It is important to check blood pressure periodically (such as at appointments with your health care provider), so that the “typical” blood pressure is known for that individual and can be compared to the blood pressure at the time of illness or change in health status.

Difference in how the autonomic nervous system functions is one reason why many people with Down syndrome have lower blood pressures. The autonomic nervous system is the part of the nervous system that acts automatically without us having to think about it. It is one of the mechanisms that controls blood pressure. The autonomic nervous system functions differently in people with Down syndrome resulting in lower blood pressure. This difference also contributes to a lower pulse (heart rate); a lower pulse can also contribute to lower blood pressure.

High blood pressure in people with Down syndrome

Hypertension can be classified as either:

Essential hypertension (high blood pressure without a definable cause)
Secondary hypertension (high blood pressure related to a definable cause)

Hypertension is very uncommon in people with Down syndrome. If hypertension is diagnosed in a person with Down syndrome, it is important to consider the possibility that it is caused by a secondary issue.

Secondary hypertension has several possible causes, including:

Abnormal endocrine function such as hyperthyroidism (overactive thyroid) and Cushing's disease (excess cortisol production)
Stenosis of the renal arteries (narrowing of the arteries supplying blood to the kidneys)
Kidney disease
Medication side effects (e.g., prednisone or certain medications used for "colds" - upper respiratory infections)

Treatment of high blood pressure

Treatment of hypertension includes:

Weight loss
- The goal is to be in the ideal body weight range, but, if a person is overweight, any weight loss may be beneficial.
Regular exercise
Limiting salt intake
- Table salt is sodium chloride. The goal is to reduce sodium intake.
Treating any secondary causes that have been identified
Medications
- There are many medications used to treat high blood pressure.

Low blood pressure in people with Down syndrome

People with Down syndrome can experience symptoms if their blood pressures are too low. The symptoms may be subtle. Some individuals have difficulty verbally expressing their symptoms so careful observation is required. Sometimes the person is “just not themself."

Some factors that may contribute to symptoms of low blood pressure include:

Fear, pain, and anxiety
- Fear, pain, and anxiety stimulate the autonomic nervous system and can cause blood pressure and pulse to decrease.
Sitting or standing up quickly
- A lowering of the blood pressure with a change in position is called orthostatic hypotension. Typically, this occurs when a person goes from lying down to sitting or standing or from sitting to standing. Dizziness is a common symptom associated with sitting or standing up quickly.
- When the body is functioning normally, the autonomic nervous system prevents orthostatic hypotension. The difference in functioning of the autonomic nervous system in people with Down syndrome contributes to orthostatic hypotension being more common.
Dehydration
- Inadequate fluid intake (dehydration) also contributes to lower blood pressure. Many of the individuals we have seen at our clinic don't drink enough fluids and are at least mildly dehydrated.
- When both dehydration and the difference in the function of the autonomic nervous system are factors, symptoms are more likely.
Reducing salt intake
- One of the treatments for high blood pressure is reducing salt in the diet. When someone in the family of a person with Down syndrome develops high blood pressure and reduces salt in their diet, often the food everyone in the family eats has less salt. We have evaluated several individuals with Down syndrome who developed symptoms of low blood pressure when the family cut back on salt when someone in the family developed high blood pressure. The reduction in the salt intake for the person with Down syndrome contributed to an even lower blood pressure and the onset of symptoms.
- Cutting back on salt for people with Down syndrome seems to be less important for people with Down syndrome since high blood pressure is much less common and cutting back may result in blood pressures that are too low.

Treatment of low blood pressure

Treatment for low blood pressure includes:

Drink adequate fluids.
- See our Tips for Staying Hydrated article for resources on hydration for people with Down syndrome.
Manage stress and anxiety.
- Since anxiety can contribute to low blood pressure, managing stress and anxiety can potentially reduce occurrences of symptoms of low blood pressure.
- See our article called Healthy Ways to Manage Stress for tips and strategies.
Understand and address pain.
- Since pain can stimulate the autonomic nervous system and contribute to lower blood pressure, knowing how a person with Down syndrome expresses pain is important.
- See our article called Pain in People with Down Syndrome for more information.
Eat and drink before getting out of bed.
- For many of the individuals we have seen at our clinic, symptoms of low blood pressure in the morning are a problem.
- These individuals often benefit by putting a few saltine crackers and a glass of water next to the bed. They eat the crackers and drink the water before rising out of bed to avoid symptoms.
- We also recommend getting up slowly and quickly sitting down if they begin to get dizzy.
- Some individuals benefit from a mild to moderate increase in salt consumption throughout the day.
Talk to your health care provider about medications.
- Some people require medications to raise their blood pressure. Midodrine (ProAmatine) is approved for use in people with orthostatic hypotension. Fludrocortisone is a steroid medication that is sometimes prescribed to raise blood pressure, but it is not Food and Drug Administration (FDA)-approved for this.

Possible connection to Alzheimer's disease

There may be a connection between lower blood pressure and Alzheimer’s disease. It is not clear if low blood pressure contributes to the onset of Alzheimer’s disease or whether having Alzheimer’s disease contributes to lower blood pressures.

In our experience, we have seen many people with Down syndrome who developed Alzheimer’s disease and then developed even lower blood pressures and lower heart rates. Researchers think Alzheimer’s disease also affects the autonomic nervous system. As Alzheimer’s disease progresses, the greater dysfunction of the autonomic nervous system may contribute to lower blood pressure and pulse. However, as noted, whether one causes the other or whether they just occur simultaneously is not clear.