Postural Orthostatic Tachycardia Syndrome (POTS) is a complex condition involving the autonomic nervous system, the body’s unconscious control center for functions like heart rate and blood pressure. This disorder is characterized by an abnormally high increase in heart rate when moving from a lying or sitting position to standing. For many individuals living with POTS, increasing daily sodium intake is a common, first-line non-pharmacological strategy recommended to manage symptoms.
Understanding the Blood Volume Deficit
When a person with POTS stands up, gravity pulls blood down into the abdomen and legs (orthostatic stress). In healthy individuals, the autonomic nervous system triggers a reflex to narrow blood vessels (vasoconstriction), pushing blood back toward the heart and brain. In many POTS patients, this process is impaired, causing excessive pooling of blood in the periphery.
This failure results in chronically low circulating blood volume, termed hypovolemia. Some POTS patients experience a moderate reduction in total blood volume. Because less blood returns to the heart, the body compensates by drastically increasing the heart rate (tachycardia) to maintain adequate blood flow to the brain. This compensatory mechanism causes defining POTS symptoms, such as dizziness, lightheadedness, and fatigue upon standing.
How Sodium Increases Circulating Fluid
Increased sodium intake directly targets hypovolemia through osmosis. The amount of sodium is a primary determinant of the extracellular fluid volume, which includes plasma. When sodium is consumed and absorbed, it raises the concentration of solutes in the plasma.
This higher solute concentration increases the blood’s osmotic pressure, creating a powerful draw for water. Water from surrounding tissues is pulled into the vascular system. The result is a measurable expansion of plasma volume and total blood volume.
Expanding the circulating fluid volume gives the heart more blood to pump, stabilizing blood pressure when standing. This expansion reduces orthostatic stress and lessens the need for a drastic compensatory heart rate increase. A high-sodium diet not only increases blood volume but also reduces standing plasma norepinephrine levels, an indicator of the sympathetic nervous system’s excessive response in POTS. This mechanism counteracts the low blood volume that drives many of the disorder’s symptoms.
Recommended Intake and Delivery Methods
The sodium recommended for POTS patients is significantly higher than standard dietary guidelines. While the typical recommendation is less than 2,300 milligrams per day, POTS patients are often advised to consume between 5 and 10 grams of salt daily. Some professionals suggest 10 to 12 grams per day, depending on individual needs. This high intake is required because the body tends to excrete sodium and water too quickly.
Patients use various methods to achieve this goal:
Delivery Methods
- Dedicated sodium chloride supplements, such as salt tablets or capsules.
- Oral rehydration solutions (ORS) or specialized electrolyte drinks.
- Adding extra table salt to food.
- Drinking broths.
The sodium must be accompanied by a substantial increase in fluid consumption, generally 2 to 4 liters daily, for blood volume expansion to occur effectively.
Monitoring and Medical Oversight
High-sodium therapy is a medical strategy and must only be undertaken with professional guidance. Monitoring is necessary to assess the therapeutic effect and guard against adverse outcomes. Regular blood pressure checks are standard because a primary risk of high sodium intake is the development or worsening of hypertension.
Periodic monitoring of electrolyte panels is also performed to ensure the high intake does not cause imbalances in minerals like potassium. High-sodium therapy is not appropriate for everyone. Patients with pre-existing conditions, particularly kidney issues or certain forms of heart disease, must be cautious. Consulting a physician ensures that the benefits of volume expansion are achieved while minimizing the risks associated with this regimen.