Aldosterone
The hormone that controls your salt and blood pressure balance
Plain English
Aldosterone is a hormone produced by the adrenal glands that regulates how much sodium the kidneys retain and how much potassium they excrete. By controlling sodium, it directly controls blood volume and blood pressure. When aldosterone rises, the kidneys hold onto more sodium and water, raising blood pressure. When it falls, sodium and water are excreted, lowering blood pressure.
The Mechanism
Aldosterone is produced in the outer layer of the adrenal glands in response to two main signals: low blood pressure (detected by the kidneys, which release a hormone called renin to start the signaling cascade) and elevated potassium levels in the blood. The full pathway from kidney signal to aldosterone release takes only minutes and operates continuously to keep blood pressure stable across changes in hydration, posture, exercise, and sodium intake.
Once aldosterone reaches the kidneys, it signals the tubules to reabsorb sodium from urine back into the bloodstream. Water follows sodium passively, increasing blood volume. In exchange, potassium and hydrogen ions are pushed out into the urine. This sodium-potassium exchange is why aldosterone directly links hydration, blood pressure, and electrolyte balance in one system. High aldosterone, whether from stress, dehydration, a high-sodium diet, or an adrenal tumor, produces high blood pressure and low potassium. Low aldosterone, as seen in adrenal insufficiency, produces low blood pressure, elevated potassium, and salt cravings.
Chronic stress is a significant disruptor of aldosterone function because both cortisol and stress hormones share the adrenal gland as their source. During sustained stress, adrenal output of aldosterone can become irregular, contributing to blood pressure variability, electrolyte imbalances, and worsened hydration efficiency. Athletes who train heavily and sweat substantially are particularly vulnerable to aldosterone disruption when sodium and potassium intake are inadequate.
Why It Matters
Aldosterone is why electrolytes matter more than water alone.
Aldosterone is the primary hormonal reason why electrolytes matter and why drinking plain water is insufficient when you are sweating or dehydrated. It is also why blood pressure rises with high sodium diets: the kidneys are following aldosterones instruction to retain it. For people tracking cardiovascular health, recovery, or athletic performance, understanding aldosterone explains why sodium intake, potassium balance, and hydration strategy are inseparable topics.
Common Misconception
Most people treat blood pressure as primarily a dietary sodium problem, but sodium only raises blood pressure to the extent that aldosterone responds to it. Some people are salt-sensitive because their aldosterone and kidney response is more reactive to sodium intake; others are not. Chronic stress raises aldosterone independently of sodium intake, which is one reason why stressed people with good diets can still have elevated blood pressure. Potassium is the electrolyte that most directly counters aldosterones sodium-retaining effect, which is why high-potassium diets consistently lower blood pressure across populations.
Signs It Is Disrupted
- Persistent high blood pressure without obvious dietary explanation
- Muscle cramps, weakness, or fatigue linked to low potassium from aldosterone-driven excretion
- Salt cravings, particularly in the afternoon, which often reflect low aldosterone and low blood sodium
- Dizziness when standing up quickly, a sign of low blood volume from insufficient aldosterone activity
- Bloating or water retention, which can reflect elevated aldosterone driving excess sodium and water retention
- Blood pressure that spikes significantly during stressful periods and does not return quickly to baseline
How to Improve It
3 Things to Remember
Aldosterone controls how much sodium your kidneys retain, directly setting blood pressure and blood volume; it is the hormonal reason why electrolyte balance and blood pressure are inseparable topics.
Chronic stress activates adrenal output and can dysregulate aldosterone independently of dietary sodium, contributing to blood pressure variability even in people with healthy diets.
Potassium is the dietary counterbalance to aldosterone-driven sodium retention; consistently high potassium intake is one of the most evidence-supported levers for blood pressure management.
Appears In
Related Terms
Protocol
Turn what you've learned into daily practice
Protocol pulls your wearable and nutrition data together into a daily health score, morning brief, and AI coaching. All in one place.
Get started free