Summer’s around the corner and with that, comes the need for some extra hydration. So, why are we writing about water and salt?
Because we can’t talk about hydration without talking about salt.
Water and salt go together. They’re attracted chemically to each other and interact when it comes to maintaining the fine balance of fluid and sodium in the body.
A massive industry has grown around bottled water and we’re commonly told by the wellness community that the more water you drink, the better. Retailers offer a huge variety of personal water bottles and many of us can’t imagine leaving home without one as we pursue the holy grail of drinking at least eight glasses of water a day.
Similarly, we’re told to consume less salt as it’s believed to cause high blood pressure and is generally bad for our health.
So it’s quite startling to discover that the recommendation of eight glasses of water a day is not supported by any research.[1] Not only that, when it comes to staying hydrated, drinking more water may not be the best strategy. Not only does drinking too much water not improve hydration, it may also cause many of the issues hydration is supposed to prevent, including headaches, skin problems, detox problems, decreased immune function and lower metabolism.
Drinking less water and eating more salt may actually be more helpful in achieving optimal hydration!
What?
Ok, let’s back up a little. There’s a lot more to hydration than simply drinking water.
First, a quick tutorial on electrolytes. These are positive or negative ions of specific minerals. Key electrolytes are sodium, potassium, calcium and magnesium. Apart from facilitating nerve and muscle function and balancing pH levels, they are essential for regulating water distribution and ensuring our cells receive proper hydration. Sodium and potassium are particularly important in this regard, as they control fluid movement across cell membranes.
Being well hydrated allows the cells to maintain their proper structure. But water is not the only factor in hydration. The ratios of electrolytes inside and outside the cell also play a role, as does the protein structure of the cell, and the amount of energy available (Adenosine Triphosphate – ATP) to move fluid across cell membranes. ATP requires magnesium to bind to it in order to function and all these factors together, interact to maintain hydration of the cell.
Hydration affects brain function and cognition (even being slightly dehydrated can result in confusion and disorientation) as well as temperature regulation, alertness and motor function. Small changes in hydration can have a big impact in your everyday performance and work, never mind athletics and sport.
Being well hydrated is necessary to maintain blood volume. Blood is the transport system that brings oxygen, glucose and other nutrients to your brain, organs and limbs as well as helping to clear waste from your system. If you’re under-hydrated, your entire system becomes sub-optimal and you’ll feel it; you’ll be sluggish, fatigued, lacking in energy.
Your body knows exactly how to manage all these processes, keeping electrolytes in balance with each other for ideal cellular energy production, and blood volume at an optimal level. However, if it doesn’t receive the nutrients it needs, the body is a master of adaptation. It will adjust to conditions in order to survive as best it can. Here’s what it will do if you decide to decrease the amount of salt you consume.
The moment your body detects you’re low in sodium, it adapts by preventing your kidneys from excreting sodium, helping you hold onto all the sodium you have. By retaining sodium, it helps keeps your blood volume stable. Smart, right? But no adaptation occurs without a cost. Retaining sodium also increases vasoconstriction (narrowing of the blood vessels) to bring the blood pressure back up.
And, by forcing your kidneys to retain sodium, they will start excreting potassium and magnesium, to maintain balanced electrolyte ratios. Remember we spoke about the importance of electrolytes to hydration earlier? So now, without enough magnesium and potassium, your hydration is being impacted. Magnesium and potassium are also important for relaxation but if they’re being eliminated, then your nervous system takes note, alerting your system to release norepinephrine, a stress hormone that gets activated when sodium levels are low. You’re now in fight or flight mode, in other words, feeling a little stressed!
The stress response, in turn, increases blood pressure. So, you can see that by cutting out salt on an ongoing basis, the lack of sodium creates conditions for both dehydration and high blood pressure.
Now let’s look at what happens when you over-hydrate. Your sodium levels may be great because you’re consuming enough salt, but since water dilutes salt, drinking too much water can mimic having insufficient sodium. It causes the same stress response described above, that results in the loss of potassium and magnesium, the same inhibition of cellular energy production and, ultimately, dehydration! Don’t make the mistake of misinterpreting the stress response as feeling more energised. Many people believe that drinking a lot of water will increase your metabolism. This is not the case. You’re feeling speedy because your nervous system is in fight or flight.
A popular myth says by the time you’re feeling thirsty, you’re already dehydrated. With all this contradictory information, how do you know how much water to drink or salt to eat?
There’s a time-honoured technology humans have been using for millennia to know when to replenish fluids; it’s called thirst. We humans have survived for a very long time and it turns out our bodies are very sensitised when it comes to thirst and hydration. Why would our biology get it so wrong as to send faulty messages about something so important? Research has shown that in fact, we get thirsty ahead of time… that’s the whole point of feeling thirst. Trust it.
If you’re exercising to the point of sweating profusely, consider adding those all important electrolytes (we like Revive) to your drinking water.
Likewise, our biology is finely tuned to register when we need to eat salt. We’re hardwired to crave salt – it’s essential for our survival. So salt your food according to taste. If your food is tasting bland and uninspiring, add salt to liven it up. Trust your taste buds.
Trust your body. It’s much smarter than you think.
[1] https://pubmed.ncbi.nlm.nih.gov/12376390/
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Disclaimer: while our blogs featuring salt and health are carefully researched and also reviewed by our qualified nutritionist and biostatician, Jacqui Niehaus, they should not be construed as medical advice. Please consider our blogs as education on how the human body processes and metabolises natural salt and its importance for our wellbeing.
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