Aldosterone – The Hormone That Balances Salt, Water, and Blood Pressure

5 min read
Updated: May 19, 2026

When people think about adrenal hormones, cortisol usually gets all the attention.

But there is another hormone produced by the adrenal glands that is just as important for survival—especially in infants and young children.

That hormone is aldosterone.

Without it, the body cannot properly control:

Salt balance
Water balance
Blood pressure
Potassium levels

And when aldosterone levels are severely disrupted, children can become dangerously unwell very quickly.

What is Aldosterone?

Aldosterone is a hormone produced by the outer layer of the adrenal gland.

Its main job is to help the kidneys decide:

How much sodium (salt) to keep
How much potassium to remove
How much water the body should retain

This sounds simple, but it is one of the body's most critical balancing systems.

Why Salt Matters So Much

Salt is not just about taste.

Sodium helps maintain:

Blood pressure
Circulation
Hydration
Nerve function
Muscle function

Children—particularly infants—are much more sensitive to disturbances in salt balance than adults.

Even relatively small shifts can lead to:

Dehydration
Weakness
Poor feeding
Vomiting
Circulatory collapse

How Aldosterone Works

Aldosterone acts mainly on the kidneys.

It tells the kidneys to:

Hold onto sodium
Remove excess potassium
Retain water alongside sodium

Where sodium goes, water follows.

So aldosterone indirectly helps maintain:

Blood volume
Blood pressure
Hydration

What Happens When Aldosterone is Too Low?

If the body cannot produce enough aldosterone:

Sodium is lost in the urine
Water follows the sodium
Potassium builds up in the blood

This can become extremely dangerous.

Symptoms of Low Aldosterone

Symptoms may include:

Poor feeding
Vomiting
Weight loss
Dehydration
Low blood pressure
Excessive sleepiness
Weakness

In infants, the signs may initially appear nonspecific.

Parents sometimes describe:

"The baby just didn't seem right."

Why Potassium Matters

One of the major consequences of low aldosterone is high potassium levels.

Potassium is essential for:

Muscle activity
Heart function
Nerve signaling

But excessively high potassium can affect the heart rhythm and become life-threatening.

Salt-Wasting Crises in Infants

One of the most important pediatric conditions involving aldosterone deficiency is:

Congenital Adrenal Hyperplasia

In the common "salt-wasting" form:

Cortisol is low
Aldosterone is also low

Affected babies may initially appear well after birth, then deteriorate over days to weeks with:

Vomiting
Dehydration
Weight loss
Shock
Severe electrolyte abnormalities

Without treatment, this can rapidly become fatal.

This is why newborn screening programs for CAH are so important in many countries.

Can Older Children Have Aldosterone Problems?

Yes.

Aldosterone abnormalities can occur in:

Primary adrenal insufficiency
Certain kidney disorders
Genetic salt-handling disorders
Rare adrenal conditions

Older children may present with:

Dizziness
Salt craving
Fatigue
Poor exercise tolerance
Recurrent dehydration

What is Salt Craving?

Some children with aldosterone deficiency develop unusually strong cravings for salty foods.

Parents may notice:

Drinking pickle juice
Excessive use of salt
Preference for salty snacks

This is sometimes the body's attempt to compensate for ongoing sodium loss.

How is Aldosterone Regulated?

Unlike cortisol, aldosterone is controlled mainly by:

Blood pressure
Kidney signals
Sodium and potassium levels

A system called the renin-angiotensin-aldosterone system (RAAS) constantly monitors circulation and fluid balance.

When blood pressure or sodium drops:

The kidneys release renin
This stimulates aldosterone production

The goal is to restore balance quickly.

How Do Doctors Test for Aldosterone Problems?

Investigations may include:

Sodium and potassium levels
Renin levels
Aldosterone levels
Cortisol testing
Blood pressure assessment

In some cases:

Genetic testing
Urine studies
Adrenal investigations

may also be needed.

How Are Aldosterone Deficiencies Treated?

Treatment depends on the cause, but may include:

Fludrocortisone replacement
Salt supplementation
Hydrocortisone (if cortisol is also deficient)

Young infants may need careful monitoring because their fluid and electrolyte balance can change rapidly.

Why This Hormone Matters So Much in Children

Adults often tolerate dehydration or electrolyte shifts better than children.

Infants and young children do not.

Their bodies:

Have smaller reserves
Lose fluids faster
Compensate poorly during illness

That is why aldosterone disorders in pediatrics are taken very seriously.

When Should Parents Seek Medical Evaluation?

Consider assessment if a child has:

Recurrent unexplained vomiting
Poor weight gain
Frequent dehydration
Persistent low sodium or high potassium
Excessive fatigue
Salt craving
Unexplained dizziness

In infants, persistent poor feeding or lethargy should never be ignored.

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