The most appropriate way to express the sodium concentration of a solution is by displaying the amount of sodium per litre, ie 1000mg of sodium per litre. It’s also a commonly used way to communicate the sodium concentration of an athlete’s sweat.
For example, my sweat sodium concentration is 1,800mg/l; as in I lose 1,800mg of sodium per litre (32oz) of sweat that I lose.
As luck would have it, Precision Hydration have named their products inline with the volume of sodium in each of the drinks. ie: PH 500 has 500mg of sodium per litre, PH 1000 has 1000mg of sodium per litre, PH1500 has 1500mg of sodium per litre when mixed as directed.
It's all about the concentration.
For example, if you take our Sweat Test and discover that you lose ~1,750mg of sodium per litre (32oz) of sweat we'd be likely to recommend that you drink PH 1500 whenever you're sweating for more than a few hours.
Now, let's say you tend to carry a 500ml (16oz) bottle with you. So, you'd mix one tablet or packet of PH 1500 into your bottle and drink that to thirst when you're out sweating. In doing so, you'd be taking in 750mg of sodium with that 500ml (16oz) of fluid, but the important thing is that the concentration of your drink is 1,500mg per litre (32oz), which would be replacing an adequate proportion of the 1,750mg of sodium you're losing per litre of sweat.
But, just why is the relative sodium concentration of my drink so important?
The relative concentration of a drink aiming to keep you hydrated is crucial because it's a key factor in determining how your body absorbs and retains the drink after it passes your lips and enters your stomach, gut and on into your bloodstream.
That’s why we always recommend mixing our drinks up as directed and why many supplements end up being used wrong; people often mix them up in way too much water, diluting the concentration down and reducing their effectiveness in terms of rehydration.
The more sodium in a drink (relative to the volume of water it’s dissolved in), the higher the “osmolality” of that solution and the more easily it’s absorbed and retained in the blood plasma (up to a certain point at least).
This is because your blood is very salty (~3,200mg of sodium per litre/32oz) and this is tightly controlled by your body, so weaker drinks can only be absorbed so much before they start to dilute the level of sodium down, which your body doesn’t like.
If you would like to learn more regarding Sodium Concentration, head on over to Precision Hydration for more details.