Aldosterone is a key hormone for the body’s balance. It plays a central role in regulating blood pressure and minerals. Understanding this blood marker helps you monitor your health better and communicate effectively with healthcare professionals. This guide details its function, associated conditions, and how to interpret your test results.
What is Aldosterone?
Aldosterone is a steroid hormone. It is produced by the adrenal glands, located above the kidneys. These glands have a fundamental role in overall hormonal balance. Aldosterone acts as a regulator. It supervises the balance of minerals and fluids in the body.
Production and Regulation
Your body produces this hormone in the outer part of the adrenal glands. This area is called the adrenal cortex. Aldosterone production responds to a series of biological signals. For example, a drop in blood pressure or blood sodium levels activates a complex system. This system, called the renin-angiotensin system, then triggers the release of aldosterone to restore balance.
Main Physiological Functions
Aldosterone’s major function is to manage sodium and potassium. It acts primarily on the kidneys. It instructs them to retain more sodium and water. Simultaneously, it promotes the elimination of potassium. This precise mechanism helps maintain stable blood pressure. It also ensures a good electrolyte balance, vital for all cells.
Why is Aldosterone Testing Important?
Doctors prescribe aldosterone testing for several reasons. It allows for evaluating adrenal gland function. It also helps identify the origin of certain blood pressure disorders.
This measurement is often associated with renin testing. Renin is an enzyme in the same regulatory system. The calculation of the aldosterone/renin ratio is therefore a very useful indicator. It helps diagnose conditions such as primary hyperaldosteronism. This condition is a frequent cause of treatment-resistant hypertension.
An undetected imbalance in aldosterone levels can have serious consequences. Chronic excess, for example, increases the risk of:
- High blood pressure that is difficult to control.
- Cardiovascular damage, such as heart enlargement or arrhythmias.
- Impaired kidney function.
- Potentially dangerous mineral imbalances.
- Strokes.
Medical decisions based on this test are therefore crucial. A high aldosterone/renin ratio may warrant imaging tests. Searching for a small benign tumor on an adrenal gland (adenoma) may then be indicated. If an adenoma is found, surgery can sometimes cure the hypertension.
How to Read and Understand Your Test Results
On a lab report, the aldosterone value is usually expressed in nanograms per liter (ng/L) or picomoles per liter (pmol/L). Reference ranges may vary slightly depending on the laboratory.
However, for guidance, normal ranges are often between:
- 30 and 160 ng/L when lying down.
- 60 and 380 ng/L when standing up.
It is essential to note that body position during blood collection greatly influences the result. Levels are naturally higher when standing. This is why the analysis report sometimes specifies this condition. Furthermore, laboratories use symbols like an asterisk (*) or color to indicate an abnormal value.
For proper reading, focus on:
- Your measured value.
- The laboratory’s reference ranges.
- The units of measurement.
- The presence of associated tests (renin, sodium, potassium).
Conditions Linked to Abnormal Aldosterone Levels
An aldosterone level outside the normal range can indicate different medical conditions.
High Aldosterone Levels: Hyperaldosteronism
Primary Hyperaldosteronism (Conn’s Syndrome)
This condition affects 5 to 15% of people with hypertension. It is characterized by excessive and autonomous aldosterone production by the adrenals. It is often due to a benign tumor (adenoma) or stimulation of both glands.
- Mechanism:Excess hormone causes significant sodium retention and potassium loss.
- Symptoms:Resistant hypertension, muscle weakness, cramps, fatigue, or increased urine volume.
- Complementary Tests: The doctor often orders a renin test (which will be low), an electrolyte panel, and adrenal imaging (CT scan or MRI).
Secondary Hyperaldosteronism
Here, the increase in aldosterone is a normal response to another condition. The renin-angiotensin system is strongly activated.
- Mechanism: A decrease in blood flow to the kidneys (dehydration, heart failure, cirrhosis) stimulates renin production, which in turn increases aldosterone.
- Symptoms:They depend on the underlying cause (edema, ascites, etc.).
- Complementary Tests: Renin testing (which will be high) is essential, as are examinations to find the cause (echocardiogram, liver function test).
Low Aldosterone Levels: Hypoaldosteronism
Adrenal Insufficiency (Addison’s Disease)
This rare disease results from the destruction of the adrenal cortex. The production of several hormones, including aldosterone, is therefore insufficient.
- Mechanism: Aldosterone deficiency causes sodium loss and potassium retention.
- Symptoms: Hypotension, severe fatigue, weight loss, salt craving, and sometimes brown skin pigmentation.
- Complementary Tests: Cortisol testing, ACTH stimulation test, and search for specific antibodies.
Hyporeninemic Hypoaldosteronism
This form is more common in people with diabetes or kidney failure. Aldosterone production is low despite stimulation by renin, which is itself low or normal.
- Mechanism: The cause is often kidney damage that produces less renin or adrenal resistance to its action.
- Symptoms: The main sign is hyperkalemia (excess potassium), which can be dangerous. Other symptoms are often subtle.
- Complementary Tests: Blood electrolyte panel and evaluation of kidney function.
Practical Advice and Follow-up
Adapted lifestyle management and regular follow-up are important.
Follow-up Schedule
- Slightly Abnormal Level: A check in 3 to 6 months is often suggested, with blood pressure monitoring.
- Moderately Abnormal Level: A medical consultation and more frequent check (1 to 3 months) are recommended.
- Significantly Abnormal Level: A prompt consultation is necessary for further examinations.
Nutritional and Lifestyle Tips
- If your level is high: Limit salt, favor potassium-rich foods (bananas, green vegetables, avocados), and avoid licorice, which mimics the effects of aldosterone.
- If your level is low: Moderate salt intake may be advised by your doctor, while being careful about foods very high in potassium.
- For everyone: Regular physical activity, good stress management, and a healthy weight contribute to overall hormonal balance.
When to Consult a Specialist?
Consult quickly if you have very high blood pressure despite treatment, severe muscle weakness, palpitations, or severe headaches associated with an abnormal aldosterone level.
Frequently Asked Questions About Aldosterone
Does the Aldosterone Level Vary During the Day?
Yes, it follows a circadian rhythm. Values are generally higher in the morning. This is why blood draws are often performed between 8 am and 10 am for better comparability of results.
Do Certain Medications Influence Aldosterone Levels?
Absolutely. Many treatments alter the results (diuretics, certain antihypertensives, anti-inflammatories). It is crucial to inform your doctor of all your medications. Temporary discontinuation, under medical supervision, is sometimes necessary before the test.
What is the Link Between Stress and Aldosterone?
Chronic stress can indirectly stimulate aldosterone production. Studies suggest that this elevation, even moderate, could contribute to long-term cardiovascular and kidney damage.
How to Interpret a High Aldosterone/Renin Ratio?
A high ratio suggests excessive and autonomous aldosterone production. This is a strong indicator of primary hyperaldosteronism. However, this result must always be confirmed by other tests.
Can Diet Influence Aldosterone?
Yes, significantly. A high-salt diet tends to decrease its production, while a low-salt diet increases it. Potassium also has a regulatory effect. A balanced diet is therefore fundamental.
Additional resources
- To deepen your knowledge of this blood marker, click here.
- To extend your knowledge and decipher other markers, more articles are available here.
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