Aldosterone and training: how sport affects hormonal balance

Aldosterone and training are inextricably linked — physical exertion activates hormonal mechanisms that help your body adapt to fluid loss and changes in electrolyte levels. This mineralocorticoid, produced by the adrenal cortex, regulates blood pressure, sodium balance and muscle function, making it particularly important during intense sporting activity.

How do aldosterone and training work together?

Aldosterone is a steroid hormone produced by the outer layer of the adrenal cortex — the zona glomerulosa. It belongs to the mineralocorticoid group and acts in the kidneys’ distal tubules and collecting ducts, where it stimulates sodium reabsorption and potassium excretion in urine. Water follows sodium by osmosis, helping maintain blood volume and blood pressure.

During training, the renin-angiotensin-aldosterone system (RAAS) is activated: sweating reduces plasma volume, blood pressure temporarily falls, and potassium released during intense muscle activity raises plasma potassium levels — all of these signals prompt the adrenal cortex to produce more aldosterone. Studies have confirmed that even moderate-intensity aerobic activity — such as treadmill running, described in Striding day at Reva-Sport fitness club. Treadmill training — significantly increases plasma aldosterone concentration (Wade and Claybaugh, 1980).

Why do aldosterone levels rise during intense training?

Several mechanisms trigger aldosterone release simultaneously during training:

• Reduced plasma volume — sweating removes fluid from your body, activating renin secretion in the kidneys and setting off the RAAS cascade, which proceeds through angiotensinogen and ultimately leads to aldosterone production.
• Increased plasma potassium levels — intense muscle activity releases intracellular potassium into the blood, directly stimulating aldosterone release from the adrenal cortex.
• Activation of the sympathetic nervous system — physical exertion and stress accelerate renin release in the kidneys.

Studies show that the aldosterone response depends directly on training intensity: the greater the training load, the stronger the hormonal response (Freund et al., 1991). Adequate electrolyte intake — for example, Science in Sport (SiS) sports products are specifically formulated to support electrolyte balance during training — may help reduce excessive RAAS activation.

Which type of training has the greatest effect on aldosterone release?

Endurance training — running, cycling, swimming and rowing — has a greater effect on aldosterone secretion than short strength training workouts. This is due to its longer duration, heavier sweating and greater fluid loss. Endurance training also leads to longer-term adaptations: a trained athlete’s blood volume increases and the RAAS response becomes more efficient — the same homeostatic outcome is achieved with less aldosterone secretion (Convertino, 1991).

At competitive sporting events such as SPA&SPORT CUP 2019, participants experience both physical and psychological stress, which can further increase aldosterone release. NIH MedlinePlus recommends paying attention to your fluid and electrolyte balance when you train, especially during longer and more intense workouts.

During strength training — barbell exercises and other weight exercises — the rise in aldosterone is more moderate and shorter-lived, but still occurs. High-intensity interval exercises (HIIT) can briefly produce hormonal responses equivalent to those seen during prolonged endurance activity, thanks to the sudden release of metabolites and potassium.

How can you support your body’s recovery after a workout?

Aldosterone remains active after a workout: the hormone helps the renal tubules retain sodium and corrects the fluid deficit caused by training. For effective recovery, it is important to drink enough fluids, including sodium-containing drinks, to help plasma volume return to normal.

Muscle care and massage support efficient circulation and speed up recovery — 2 massages=3 at Planet Sport in Tartu offers a practical, affordable way to make regular recovery treatments part of your training routine. Hew-Butler and colleagues (Hew-Butler et al., 2015) emphasize that monitoring electrolyte and fluid balance after training is particularly important following longer workouts, to prevent both dehydration and hyponatremia caused by excessive water intake.

Overall, aldosterone is an essential hormone for adaptation to training, helping your body maintain its internal balance even under maximal training loads. A balanced diet, adequate hydration and planned recovery periods are usually enough to support its normal function.

References

• Wade CE, Claybaugh JR (1980). Plasma renin activity, vasopressin concentration, and urinary excretory responses to exercise in men. J Appl Physiol Respir Environ Exerc Physiol. 49(6):930–6. PMID: 7380697
• Freund BJ, Shizuru EM, Hashiro GM, Claybaugh JR (1991). Hormonal, electrolyte, and renal responses to exercise are intensity dependent. J Appl Physiol. 70(2):900–6. PMID: 1778903
• Convertino VA (1991). Blood volume: its adaptation to endurance training. Med Sci Sports Exerc. 23(12):1338–48. PMID: 1943629
• Hew-Butler T, Rosner MH, Fowkes-Godek S, et al. (2015). Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clin J Sport Med. 25(4):303–20. PMID: 26111144

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