Hypotension

Hypotension is a condition characterized by abnormally low blood pressure, defined as a systolic pressure of less than 90 mmHg (millimeters of mercury) or a diastolic pressure of less than 60 mmHg.

Hypotension can cause symptoms such as dizziness, weakness, fainting, and, in severe cases, shock.

Chronic low blood pressure (usually below average levels but not at dangerous limits) is common.

Some athletes may have blood pressure lower than normal for their age due to frequent exercise, even though their cardiovascular system is completely normal.

Hypotension can also be caused by various medications, including antihypertensive drugs.

Among other situations, hypotension typically occurs in the following cases:

• Dehydration: This can result from fever, diarrhea, vomiting, or excessive heat.
• Heavy bleeding.
• Heart diseases: Such as cardiac arrhythmias and valvular heart disease.
• Hormonal disorders: Such as Addison's disease (adrenal insufficiency) and hypoglycemia (low blood sugar).
• Pregnancy.
• Serious infections.
• Severe allergic reactions.
• Anemia.
• Orthostatic or postural hypotension: This occurs when a person stands up suddenly.

If blood pressure falls below dangerous limits, as can occur in major hemorrhages in a condition called hypovolemic shock, it can be life-threatening.

Shock can be caused by serious heart problems, trauma with significant blood loss, severe infections, and other circumstances.

When blood pressure drops, a person may experience:

• Dizziness
• Confusion
• Fatigue
• Nausea
• Wet and cold skin
• Paleness
• Rapid and shallow breathing
• Rapid but weak pulse
• Syncope (loss of consciousness)

In cases of shock, these symptoms worsen rapidly and can eventually lead to cardiac arrest.

Orthostatic or postural hypotension is the most common type of hypotension.

It is defined as a decrease of 20 mmHg in systolic blood pressure or 10 mmHg in diastolic blood pressure at least 3 minutes after rising from a lying or sitting position.

Symptoms may include dizziness or even frequent loss of consciousness (syncope), which can occur when standing up quickly from a sitting position. It is more common after spending a long time in the sun or after a prolonged fast.

The cause is often unclear, but sometimes starting medications for high blood pressure can trigger these sudden drops in blood pressure. In such cases, the doctor will assess the need to make any changes to antihypertensive therapy.

Treatment includes getting up slowly and performing movements that help compensate for hypotension, such as clenching your hands and tensing your arms or crossing your legs when you feel dizzy to avoid syncope.

Often, symptoms also improve with increased hydration and salt consumption, always under medical supervision to determine whether it is necessary to prescribe medications.

In addition to orthostatic hypotension, there are other types of hypotension:

• Postprandial hypotension: This occurs after eating (within 1 or 2 hours) when much of the blood flow is redirected to the digestive system, causing a drop in blood pressure. It is common in older adults with normally high blood pressure or those who have Parkinson's disease.
• Neurally mediated syncope: This occurs when a person stands for a long time. Blood pressure drops due to a lack of communication between the brain and heart. It is common in young adults and children.
• Multiple system atrophy with orthostatic hypotension (Shy-Drager syndrome): This is a rare disorder that affects the autonomic nervous system, which controls involuntary functions of the body, such as blood pressure. It presents with symptoms very similar to those of Parkinson's disease.

The treatment depends on the underlying cause.

In individuals with orthostatic or postural hypotension, it can be prevented by sitting up more slowly or getting out of bed in stages. Hypotension without other associated symptoms typically does not require treatment.

However, if you have experienced one or more episodes of syncope or dizziness, you should consult your doctor, who will determine whether you need to be evaluated by a specialist.