It’s important to be balanced in all areas of life, but most of all on a molecular level.
Our hormones, vitamins, minerals, fluids and temperature are all constantly changing, but they also have to stay in balance with each other. At every moment of our existence, our bodies are working hard to maintain a delicate equilibrium of a thousand different things.
Luckily, making sure all our weirdly-named juices are in perfect proportion isn’t something we usually need to think about. We have a system that automatically does it all for us: the endocrine system.
Usually the only awareness we have of our own hard work is when we menstruate, feel thirsty, or hungry, or too hot, or tired: conscious manifestations of a long, complicated internal process.
Given all that, you’d think managing something as simple as salt would be easy. But when it comes to the saltiness of your body, things can get quite complicated quite quickly.
Things that shake your salt levels
Humans, like all other land animals, contain a private inner ocean. The saltiness of this ocean is supposed to stay pretty much constant, but is affected by things like dehydration, over-hydration, heat, and the efficiency of your organs.
“Hyponatraemia is low sodium in the blood, which often is caused by water retention (rather than a deficiency of salt) leading to the body becoming ‘diluted’,” says Dr Annabelle Warren, endocrinologist and NHMRC-funded PhD researcher with the University of Melbourne and Austin Health.
If you drink 10 litres of water one day or your kidneys forget what they’re doing, you can end up with too much fluid in your body, like a bland human-flavoured soup.
Low salt levels can also occur as a side effect of medication, organ failure, or your body releasing too much of the water-retention hormone ADH, which can happen if it’s trying to deal with another underlying condition.
Heatwaves are also a trigger, especially for people over 65. When the weather warms up it can be easy to drink too much or too little, or for sick people to get sicker under the strain of trying to keep cool.
“An association has been seen around the world between increased heat and higher rates of low sodium. We looked at data from the last 10 years at our own hospital and found this correlation held true, with more hospital admissions for hyponatraemia during heat waves,” notes Annabelle.
Unfortunately, summers are only getting hotter and hotter, and that’s not good news for people who plan to be over 65 in the future.
“With climate change on track to cause more frequent and severe heatwaves both in Australia and globally, alongside other disruptions, we may expect hyponatraemia hospitalisations to become more common.”
“This is yet another health-related reason to transition away from fossil fuels to limit greenhouse gas emissions and minimise this impact.”
When you’re feeling less than savoury
If you feel unbalanced, your salt might be too.
Low salt can make you feel unsteady, leading to stumbling, clumsiness, or falling more than usual. It can become difficult to think, and you might feel nauseous and confused. In the worst case scenario, excess water might cause swelling around your brain, which could result in vomiting, seizures, or even a coma.
These symptoms look similar to heatstroke, low blood sugar, or a bad infection, but the difference with hyponatraemia is that it comes on slowly over hours or days and isn’t directly tied to a single cause like being out in the hot sun or going too long without food.
Even stranger, the severity of your symptoms doesn’t always match how low your sodium actually is. A small, sudden drop can make you feel awful, while a slow, serious decline might barely register.
“The number doesn’t always line up with the symptoms, and if the sodium has been dropping gradually you can have a very low blood level but might not have many symptoms,” warns Annabelle.
The saline solution
But don’t think you just can drink a litre of soy sauce and call it a day.
Coming up to a normal salt level is like coming up from a deep ocean dive – it needs to happen slowly.
“When the sodium has been low for a long time and any treatment is started, it is important to monitor the sodium level to make sure it doesn’t rise too quickly,” explains Annabelle.
In cooking, salt draws out water – it’s why you might rub an eggplant or steak with rock salt before grilling it. It’s not so different for human bodies. When a person’s had low salt for a while, their cells are filled with excess water and are extra plump and juicy. If too much salt is added too quickly, all this water gets suddenly pulled out of the cells, upsetting their balance at a time when they’re already under stress.
“Water exiting the brain cells rapidly causes a kind of ‘shrivelling’,” says Annabelle, “which can cause serious brain damage called osmotic demyelination syndrome.”
The opposite can happen too: if the sodium level drops too quickly, cells expand as water rushes in, which can lead to dangerous swelling.
This happens all over the body but affects the brain most of all; since there’s no wiggle room in a skull, sudden changes in pressure can cause damage.
So instead of raising salt rapidly, doctors usually try to restore your balance by slowly reducing the water in your body instead.
“Because chronic low sodium is often due to ‘water excess’ the treatments we use aim to reduce this extra water” Annabelle says.
Depending on what caused your low salt, doctors might ask you to drink less water for a few days, give you an IV of salty water, or adjust your medication.
Salt levels are part of a basic blood test, so hyponatraemia is usually picked up pretty quickly if you go to hospital.
But to avoid going there in the first place, Annabelle has some advice. “Drink according to thirst in hot weather and when active, and don’t drink excessive water if you don’t feel thirsty.”
And stay indoors – if you can. As Annabelle notes, “access to adequate shelter and cooling is also an important health equity issue globally as the climate warms.”
Staying salty
Salt is very important, and if you don’t have enough of it things can get really serious.
We’ve all been told to stop eating so much salt, so it’s surprising that too low sodium is actually one of the most common issues doctors see in hospital patients.
This isn’t because we’ve collectively given up chips as a nation, but because we’re all getting older, we’re collecting more chronic conditions, and the weather’s getting hotter.
As the world warms up, it becomes easier for the balance to tip over – not only in the environment but in our own bodies.
Low salt might seem like more a problem for your lunch than your grandmother, but it’s a reminder that even our basic cellular chemistry is bound to the planet we live on.
