Why More Sodium Isn't Better for Hydration

The Science Behind Optimal Electrolyte Concentration

When you push your body during prolonged endurance training or extreme sauna heat, hydration isn't just about what you drink — it's about what your body can actually absorb. A strong trend in the industry is overdosing sodium to 1,000mg or more per serving. But physiological data shows that human sweat averages around 926mg of sodium per litre. If you mix one serving of Mova Pure (800mg sodium) in a standard 450–750ml bottle, you match your body's natural sweat concentration almost perfectly. Forcing more concentrated salt into too little water makes your stomach work against you — leading to cramping and delayed fluid uptake. Here is the scientific explanation for why precision beats marketing hype.

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Human Sweat Is Hypotonic: What the Science Actually Shows

To understand how we should drink, we first need to look at what we actually lose. In a comprehensive physiological analysis of 1,944 sweat tests across 1,304 athletes, the median sodium loss was established at 40.3 mmol/L — equivalent to approximately 926mg of pure sodium per litre of sweat.

Blood plasma has a significantly higher sodium concentration (135–145 mmol/L). This means your sweat is hypotonic (less salty) relative to your blood. Because you lose more pure water than salt during a session, blood osmolality rises. The primary goal of rehydration is therefore to rapidly replace free water alongside a precisely balanced amount of electrolytes — not to overload the system with hyperconcentrated salt solutions.

• Human sweat (average): ~926mg sodium/L
• Mova Pure (750ml mix): ~1,066mg sodium/L — within the optimal window
• High-dose competitors: 2,000mg+ sodium/L — hyperconcentrated

Physiological Parameter	Mova Pure (mixed in 750ml)	High-Dose Formula (mixed in 1 litre)
Sodium concentration	~1,066mg/L — within optimal window	~1,000mg/L — upper limit of sweat range
Gut comfort (buffering)	High — Sodium Citrate provides alkaline buffer	Low — pure NaCl can irritate the intestinal lining
Absorption speed	Fast — 1,000mg Glycine drives active uptake via SGLT1	Slow — passive diffusion only
Stomach sloshing	Minimal — compact and ergonomic fluid volume	High risk — requires large fluid volume during movement
Sweetener & purity	Thaumatin only (sweet protein) + Rice Fiber	Stevia (bitter aftertaste) + synthetic fillers

Note: A 1,000mg sodium sachet mixed in 500–750ml — as most athletes do in practice — creates a hypertonic solution of 1,300–2,000mg/L, which works against absorption rather than for it.

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Why High-Sodium Electrolytes Cause Stomach Cramps

The journey from your bottle to your working muscles is controlled by two phases: how quickly your stomach empties (gastric emptying) and how efficiently the small intestine absorbs the fluid.

When you drink a solution containing 1,000mg sodium in less than 500ml of water, you create a hypertonic environment in the gut (concentrations of ≥2,000mg/L). This triggers an unfavourable chain reaction:

• Osmotic fluid shift: Because the gut strives for balance, your body is forced to pull water from the blood into the intestinal lumen to dilute the concentrated salt.
• Temporary dehydration and GI distress: This shift causes an acute drop in plasma volume, while the accumulated water in the gut stretches the intestinal walls — triggering nausea, bloating, cramping, and osmotic diarrhoea mid-session.
• Delayed hydration: Your muscles wait for their water while the gut slowly clears the excess salt.

By delivering 800mg sodium per 450–750ml, Mova Pure stays firmly within the hypotonic to isotonic window (200–270 mOsm/kg). Water is pulled quickly and passively into the bloodstream without irritating the gut lining.

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How Mova Pure Accelerates Absorption Beyond Plain Salt Water

Glycine as a transport driver: By including the amino acid Glycine, we activate sodium-coupled transport via the SGLT1 pathway. When glycine is transported alongside sodium, it creates a localised micro-osmotic pressure that pulls water molecules into the cells through so-called "solvent drag" — delivering faster hydration than plain salt water can achieve.

Protection against "leaky gut": During hard training or sauna, up to 60–80% of blood is diverted away from the gut to muscles and skin for cooling. This oxygen deprivation (ischaemia) damages the gut's delicate tight junction proteins, temporarily making the intestinal barrier "leaky" and triggering inflammation and nausea. Research shows that glycine acts as a direct building block for the body's antioxidant defence (glutathione), protecting cells against this stress and preserving gut barrier integrity.

Magnesium Malate for cellular energy: For the gut to pump sodium and water efficiently, it needs energy in the form of ATP. Mova Pure uses Di-Magnesium Malate — an organic chelate that, unlike cheap magnesium oxide, is highly bioavailable and extremely gentle on the stomach. The malic acid (malate) component directly feeds the Krebs cycle to support aerobic energy production at a cellular level.

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How to Find Your Optimal Electrolyte Dose

• Standard endurance training (450–750ml water): Mix in a larger bottle. This delivers an optimally balanced, slightly hypotonic solution that maximises fluid uptake and helps sustain endurance performance during prolonged training — fully in line with EFSA guidelines.
• Extreme sweat loss and sauna (450ml water): For very high sweat losses over a shorter time — such as intense sauna sessions — mix in less water to deliver a more concentrated electrolyte dose. Thanks to the glycine and magnesium malate, the formula remains gentle on the stomach even at this higher concentration.

Not sure where your session sits on the curve? Use our Sweat Calculator to calculate your estimated sodium and fluid deficit based on your weight, sport, and intensity →

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Mova Pure: Engineered in Finland. Perfected in Sauna.