tuneTypical Dose
1500–2300
Mineral
Sodium
Sodium (Na, element 11)
Evidence TierAWADA NOT PROHIBITED
watchEffect Window
Acute, minutes to hours for volume and symptom response.
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
Sodium is an essential electrolyte for fluid balance, nerve impulses, and muscle contraction. It is used to replace sweat losses during prolonged exercise and to reduce hyponatremia risk in high-loss conditions.
Sodium replacement improves hydration maintenance during prolonged heavy sweating by supporting plasma volume and reducing hyponatremia risk. Some evidence suggests improved endurance performance when sweat sodium losses are high. Minority clinical contexts include support for orthostatic intolerance under supervision. Excess sodium intake can raise blood pressure in salt-sensitive individuals, so net benefit depends on matching intake to losses.
Primary extracellular cation regulating fluid volume, blood pressure, osmotic balance, and neuromuscular signaling via Na+/K+ ATPase.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Electrolyte balance
- Hyponatremia prevention during endurance exercise
- Fluid volume maintenance
Secondary Outcomes
- Keto-flu symptom relief during low-carb adaptation
- Blood pressure support in POTS/orthostatic intolerance
Safety
Contraindications and Interactions
Contraindications
- Uncontrolled hypertension
- Congestive heart failure
- Significant kidney disease
Side effects
- Edema
- Water retention
- Increased blood pressure with excess
Interactions
- Lithium (sodium levels affect lithium clearance)
- Diuretics (alter sodium/fluid handling)
Avoid if
- Sodium-sensitive hypertension
- Fluid-overload states without clinician supervision
Evidence
Study-level References
sodium-SRC-001Consensus statement with supporting human exercise evidence
Sourceopen_in_newHew-Butler T, et al. 2015 Exercise-Associated Hyponatremia Consensus (plus workbook synthesis notes)
Population: Endurance athletes and prolonged-exercise cohorts
Dose protocol: Sodium replacement aligned to sweat loss and event conditions. Workbook highlights 500 to 1000 mg/hour sodium in heavy sweat heat contexts
Key findings: Appropriate sodium replacement reduces exercise-associated hyponatremia risk and supports intravascular volume during prolonged exertion. Sodium effects are bidirectional: can improve orthostatic tolerance/BP in low-volume states (for example POTS) while worsening hypertension/fluid-overload risk in susceptible users.
Notes: Workbook synthesis emphasizes nuanced sodium targets by context (athletes/low-carb adaptation vs excess-risk general intake).
Paper content
Appropriate sodium replacement reduces exercise-associated hyponatremia risk and supports intravascular volume during prolonged exertion. Sodium effects are bidirectional: can improve orthostatic tolerance/BP in low-volume states (for example POTS) while worsening hypertension/fluid-overload risk in susceptible users.
sodium-SRC-002Randomized, placebo-controlled crossover trial.
Sourceopen_in_newEarhart EL, Weiss EP, Rahman R, Kelly PV. Effects of oral sodium supplementation on indices of thermoregulation in trained, endurance athletes. J Sports Sci Med. 2015;14(1):172-178. PMID:25729305.
Population: Trained endurance athletes.
Dose protocol: 1800 mg oral sodium supplementation versus placebo before 2-hour exercise at 60% HRR in trained endurance athletes
Key findings: High-dose sodium supplementation did not improve thermoregulation, cardiovascular drift, or performance in trained endurance athletes.
Notes: Important negative evidence. Supports the view that sodium benefits are primarily about hyponatremia prevention rather than ergogenic enhancement.
Paper content
This crossover trial tested 1800 mg oral sodium supplementation versus placebo in 11 trained endurance athletes during 2-hour exercise sessions followed by time-to-exhaustion testing. High-dose sodium supplementation did not improve thermoregulation, cardiovascular drift, or performance. Both conditions produced similar sweat rates, dehydration levels, and heat stress measures. The study provides important negative evidence, cautioning against the assumption that sodium supplementation universally benefits endurance athletes and highlighting that the primary role of sodium is hyponatremia prevention rather than thermoregulation or performance enhancement.