Sport Performance

It’s no secret that the intense physical demands of competitive sport accelerate us towards dehydration, lactic acid build-up, muscle cramping & fatigue. However, when it comes to guarding against, alleviating or recuperating from such issues, there exists a public misconception that isotonic sports drinks are a big part of the solution. In this series of articles, I hope to shine a spotlight on such fallacies, and present logical, evidence-based arguments against them, so that you might be better equipped to make your own informed decisions about the food that fuels you.


The marketing & media trickeries of prominent sports drink corporations have an important role to play in our penchant for their high-sugar, calorie-dense concoctions. Pro-athlete endorsement deals, dazzling commercials & gaudy sponsorships have, for years, perpetuated a belief that they are the number one choice when it comes to rehydration and replenishment. And who are we to question them? I mean, if Michael Jordan and Lebron James are telling you it’s natural to reach for a Gatorade then “I’ll have some of what he’s having” right?

Listen, I get it, I’m not saying that sports drinks are evil. I just think that, for quite some time, we’ve been misinformed about their imperfections. In many, but not all cases, the bigger a corporation gets, the colder they become; the less they care about the needs of the individual, and the more they care about money. Heed the following statement: –

Good health makes a lot of sense, but it doesn’t make a lot of dollars” – Dr Andrew Saul

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If we can better understand the science underlying rehydration & replenishment then we can make better decisions about our own dietetic needs. We need to avoid drinking a lot of unnecessary nasties and think twice about gulping down bottles of Gatorade, just because Lebron James told us to. We must understand that there is no one-drink-fix-all solution. What works well for some individuals, might not work as well (if at all) for you. When it comes to dietetics, quite often you’ll find that the person best suited to looking after your best interests is a well-informed you; and the old maxim rings true – give a man a fish, feed him for a day; teach him how to fish, feed him for a lifetime.


Body Water

Gatorade’s less glamorous cousin, good old high-quality H2O. Before proceeding, it’s important that we differentiate between plain water (which we consume) and water as it exists in our bodies, as we must be absolutely clear that their relative compositions are not one in the same – more on this later. Body water has a multitude of different biological functions; from cell structure maintenance and thermo-regulation, to the lubrication of organs, muscle tissue & joints. Crucially though, it serves as a nutrient transportation system that affords the circulation of ions throughout the entire body; ions which carry the electrical energy necessary for muscle contractions & synaptic nerve impulse transmissions…. movement, to you & I.

Ions are formed by a process of dissociation from compounds called electrolytes, which I’m sure you’ve heard of. When electrolytes are found in a solution (e.g. bodily fluids) they dissociate to form either positively charged ions (cations – sodium, potassium, magnesium, calcium) or negatively charged ions (anions – bicarbonate, phosphate, chloride). The reason for explaining this will become clear when we take about the importance of electrolytes in the replenishment of energy. Right now, though, what matters is that we’re acutely aware that the location of these electrolytes in body water is not consistent across all body fluid compartments; with varying concentrations of each existing in extracellular fluid, intracellular fluid & blood plasma etc. It is absolutely vital that the body maintains this delicate distribution of electrolytes.


Plain Water

Despite its many benefits, plain water has its limitations when it comes to its capacity to replenish energy stores. You see, unlike body water, plain water doesn’t contain a concentration of electrolytes substantial enough to replace those lost during physical activity.

Body water does not equate to plain water, insofar as their relative solute concentrations are different.

A low concentration of electrolytes, and simple carbohydrates, gives plain water the property of being readily absorbed into the body’s cells, because, once consumed, it is a hypotonic solution. This means that since the concentration of water outside our cells is greater than what’s inside our cells; and the relative concentration of solute particles in the water is less than what is inside our cells – water will readily move into our cells.

To put it simply, when it comes to rehydrating, plain water has your back. However, when we only drink plain water – whether prior, during or after physical activity – we neglect the importance of replenishing electrolytes. The common result is that we create a state of positive water balance (excess water) – where water flows through the body all too quickly without providing the necessary electrolytes (and simple carbohydrates) to kick-start the recovery process & replenish depleted energy stores.

Remember that delicate distribution of electrolytes we mentioned earlier? Well, as it turns out, we can’t afford to neglect it.

When we lose body water during exercise, through accelerated sweating & breathing, we lose much more than just water; we lose the solute particles (ions) that comprise it. So, if we want to maintain the delicate distribution of electrolytes in the body, it’s equally as important to consume important electrolytes as it is water. To give context, when we are adequately hydrated, ions can get around easily, enabling nerve impulses to travel fluidly, muscles to contract readily & lactic acid to be reliably expelled from the muscles. Dehydration and electrolyte depletion wreak havoc with this delicate distribution, and have an adverse effect upon these biological processes. We must understand that drinking plain water is a solution to the symptoms of dehydration, but not electrolyte replenishment. Water is only half the answer.

Rehydrating with just water means that whilst the nutrient transportation system of your body might be well oiled, topped up & running smoothly, the nutrients available for transport continue to deplete. The metaphorical equivalent is a station stocked full of trains that run on time, but void of passengers (electrolytes / ions) to transport to where they’re needed most. To clarify, whilst water might be the optimal choice for hydration, it falls short in the replenishment of energy stores, due to its electrolyte composition.

From this, many relevant questions emerge, namely, if water can adequately satisfy our hydration requirements, then: –

(a) how might we replenish depleting energy stores during physical activity?

(b) how might we fill energy stores prior to physical activity?

(c) how might we re-stock depleted energy stores after intense physical activity?

To aptly address these queries, we must seek first to understand the importance of electrolytes.


In my next article of this series, I will discuss electrolyte replenishment and its importance in sustaining optimal athletic performance. I’m keen to present information in way that is clear and accessible for parents & parents so that they may be adequately equipped to deal with a future in sport; enabling young players to better prepare for, react to & recover from intense physical activity.

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