Do you need potassium, magnesium and calcium in your sports drink?

By Abby Coleman | 7 Minute Read

Sodium is the main electrolyte lost in sweat and this electrolyte should be the focus for athletes when considering which sports drink they want to use to hydrate. 

But what about the minor electrolytes - potassium, magnesium and calcium? How important are they? 

We do lose all three in sweat too, just to a far lesser extent than sodium, as we shall discuss here... 

Contents:

  1. The importance of sodium for hydration
  2. Do you need potassium in your sports drink?
  3. Do you need magnesium in your sports drink? 
  4. Do you need calcium in your sports drink?
  5. How much potassium, magnesium and calcium do PH drinks contain?
  6. Further reading

 

The importance of sodium for hydration

Sodium is the main electrolyte in the extracellular fluid (the fluid outside the cells) where sweat is directly drawn from. Sweat sodium concentration can vary significantly from person-to-person because of differences in the CFTR* duct’s reabsorptive ability.

*Cystic fibrosis transmembrane conductance regulator (CFTR): The duct in our sweat glands which sweat passes through on its journey to the skin. During sweat’s movement through the CFTR duct, sodium is reabsorbed in varying degrees between individuals. The reason for this difference in reabsorptive ability is believed to be largely genetic.

When it comes to the minor electrolytes of potassium, magnesium and calcium, athletes seem to be less sure on where they stand and what they should be consuming. 

Potassium, magnesium and calcium are worth talking about because, alongside sodium, we do also lose them in our sweat, just in far smaller proportions.

A few studies have tried to quantify exactly how much of each we lose when sweating and, whilst the numbers are a little varied (most likely due to the differences in sampling technique, sample sites, timing, and experimental conditions), the research generally agrees that the losses are minimal...

 

Do you need potassium in your sports drink? 

Potassium is the most abundant positively charged ion in the intracellular fluid (that’s the fluid inside our cells), followed by magnesium. Potassium plays a role in several bodily functions, including regulating fluid balance (alongside sodium), facilitating the transmission of nerve signals and assisting in muscle contractions.

Potassium levels in the body are regulated in much the same way as sodium is, with dietary intake being balanced predominantly by excretion through urine and a lesser quantity is lost in sweat.

Potassium sweat losses are reported to be in the region of 5 mmol/L, the equivalent to ~200 milligrams per litre (mg/L) of sweat (Jeukendrup & Baker, 2014).

If you’re a long-term user of PH, have had an Advanced Sweat Test or know a thing or two about sweat sodium losses, you’ll be aware that this loss of potassium is relatively small versus that of sodium.

To illustrate, the average sweat sodium concentration from the thousands of Sweat Tests we’ve conducted is just under 1000 mg/L, with some individuals losing far greater amounts (>2000 mg/L).

The imbalance of sodium and potassium across the fluid compartments is maintained by the sodium-potassium pump. Maintenance of this distribution of electrolytes between the intracellular and extracellular fluid is critical for cell function and electrical communication throughout the body.

Because of the relatively small losses of potassium that occurs through sweat, it’s highly unlikely that these losses alone would be substantial enough to cause a decline in performance.

On the whole, it’s thought that potassium losses only become impactful if you sweat heavily on a regular basis and your diet is chronically potassium-deficient.

Before you panic that this could be applicable to you, a diet with inadequate potassium intake would have to be void of foods like potatoes, sweet potatoes, bananas, oranges, mushrooms, and lots of other fruits and vegetables.

So, I don’t know about you, but it sounds pretty tough to avoid all of those foods, right?

Some early research on rats suggested that a potassium-containing beverage may be important in enhancing recovery by aiding intracellular rehydration.

But, a later study in humans, which saw participants drink potassium or sodium-containing beverages when dehydrated following exercise, showed that rehydration rate was slowest in the potassium-only beverage and lent further support to the importance of sodium.

 

Do you need magnesium in your sports drink?

We’ve already touched upon magnesium but let’s talk more about it.

As mentioned before, it’s held in the intracellular fluid, mainly along with potassium, and is needed for more than 300 biochemical reactions in the body. Dietary magnesium mainly comes from dark green, leafy vegetables but other good sources include fruits, nuts and whole grains.

Although there can be a decline in plasma magnesium concentration during exercise, it's most likely to be due to the redistribution between fluid compartments rather than sweat loss.

Sweat losses of magnesium have been found to be much smaller than those of potassium - somewhere in the region of 0.1-0.5 mmol/L; the upper range being equivalent to ~12 milligram of magnesium per litre of sweat (Jeukendrup & Baker, 2014). So, pretty small, right?

A depletion of potassium and/or magnesium has previously been suggested to be implicated in the etiology of exercise-associated muscle cramping, but there's been little to no experimental data to support this (Shirreffs, 2003).

 

Do you need calcium in your sports drink? 

Calcium is essential to maintaining total body health. Your body needs it every day, not just to keep your bones and teeth strong, but to also ensure proper functioning of muscles and nerves (Piste et al., 2012).

The loss of calcium in sweat is (you guessed it!) small.

In the literature you can find a range of 0.1 to 1.3 mmol/L (Hoshi et al, 2001; Shireffs & Maughan, 1997; ), so fittingly, Jeukendrup & Baker report an average of ~0.5 mmol/L (~20 mg/L). Because the calcium loss incurred through sweat is minor, much like magnesium, the evidence for its inclusion in sports drinks is limited.

 

How much potassium, magnesium and calcium do PH products contain? 

Firstly, any water (tap or bottled) that you drink, unless labelled 'distilled', will contain traces of all the minor electrolytes.

When you mix PH 500, PH 1000 or PH 1500 low-calorie effervescent tablets as directed (i.e. in ~500ml (16oz) of plain water) you get a solution with 250mg potassium, 48mg calcium and 24mg of magnesium per litre (see our blog on the importance of working in relative concentrations).

Our US customers receive tablets containing slightly different quantities of each - 260mg potassium, 40mg calcium and 20mg of magnesium.

Since we began manufacturing our US tablets in the US we had to make some minor adjustments to their composition (manufacturing guidelines, I’m afraid...), but we figured this was a small price to pay in order for our US customers to receive US-manufactured tubes and benefit from reduced shipping times (not to mention a reduced carbon footprint too!).

And fear not, wherever you’re based, everyone is receiving a product containing a quantity of minor electrolytes in-line with your sweat losses, we made sure of that.

If you’re wondering 'what about the all-natural drink mixes?' Their minor electrolyte composition matches that of the rest-of-the-world (ROW) tubes and, no matter your country of residence, everyone receives the exact same formula.

Now that’s more straight-forward isn’t it, why can’t everything be a bit more like our all-natural drink mixes?

 

Minor Electrolytes

Average loss in sweat (mg/L)

(Jeukendrup & Baker, 2014)

PH Content (mg/L)

USA low-calorie effervescent tablets

ROW low-calorie effervescent tablets and all-natural powder mixes

Potassium

200

260

250

Magnesium

12

20

24

Calcium

20

40

48

 

Take a step back

Whilst it’s interesting to look at the nitty-gritty of what we lose in our sweat, and good to know that PH provides you with what you’re losing, let’s end by taking a step back and remembering the bigger picture: sodium.

Sodium is and always will be the heavy-hitter when it comes to electrolyte replacement and this isn’t going to change. Noting your drink’s sodium content first and foremost, and getting this intake correct, is of far greater priority than any of the other electrolytes.

 

Further Reading

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