What Is Sodium?
Sodium is the main cation of extracellular fluid and arguably the most important electrolyte for athletes. It regulates blood volume, blood pressure and nerve impulse transmission. During intense training, 500-2,000 mg sodium per hour is lost through sweat — this can cause hyponatremia, a dangerous condition when blood sodium is too low.
🏋️ Sodium Functions in Sport
💧 Fluid Balance
Sodium is the main regulator of osmotic pressure. It retains water in the body and ensures that blood volume remains sufficient for oxygen transport.
⚡ Nerve and Muscle Function
The sodium-potassium pump is responsible for every nerve impulse and muscle contraction. Without sufficient sodium, signals slow down and cramps occur.
🌡️ Thermoregulation
Sufficient sodium helps the body cool more efficiently through sweating. Hyponatremia disrupts thermoregulation and increases the risk of heat stroke.
🔄 Recovery
After training, sodium helps restore fluid balance faster. Drinking water without sodium is excreted faster in urine — with sodium, it stays in the body.
📊 Sweat Composition and Sodium Losses
| Parameter | Significance | Notes |
|---|---|---|
| Sodium concentration in sweat | 400-1,200 mg/L | Depends on genetics and acclimatization |
| Average sweating | 0.5-1.5 L/h | A function of intensity and temperature |
| Sodium losses per hour | 200-1,800 mg/h | Huge individual variation |
| Salty sweaters | >1,200 mg/L | A sign: white stains on clothing |
| After 2 h without Na replenishment | -5-15% plasma volume | Direct decrease in endurance |
📋 Recommendations for Athletes
- Before training: 300-500 mg sodium with 500 ml water 1-2 h before
- During training: 300-700 mg sodium per liter of water, especially if >90 min.
- After the workout: 500-1,000 mg sodium with food or an electrolyte drink
- For weight-loss athletes: Do not restrict sodium drastically — this will cause weakness and cramps
🛒 Recommended Products
❓ FAQ
Should athletes limit salt?
It depends on the context. For an office worker — yes, it should be limited. For an athlete training 2+ hours per day and sweating heavily — no. Such athletes may not have enough sodium. It is important to assess individually.
How do I find out how much sodium I lose?
The simplest way: weigh yourself before and after training. Every 0.5 kg weight loss = ~500 ml sweat = 200-600 mg sodium. A more professional way — a sweat sodium concentration test in a laboratory.
When are salt tablets needed?
In ultra-endurance events (>4 h), in heat waves, or if you are a salty sweater. For most athletes, sports drinks are sufficient. Salt tablets without enough water can cause nausea.