Salty Educator, Liz Jemson-Ledger, Neurological Physiotherapist, joins us to talk all things electrolytes, brain health, concussion recovery.
Around 75% of our brains are made up of water so It’s no wonder that staying well hydrated is essential for keeping your brain sharp and functioning at its best. But it's not just about drinking enough water, it's also about keeping the balance of fluids inside and outside your brain cells just right. That’s where electrolytes like sodium and potassium come in. These minerals help to regulate where water goes to keep the concentration of these fluids in proper balance.
When we don’t drink enough water, or if we lose too much through sweating, vomiting, or diarrhoea, we can become dehydrated. And when that happens, we’re not just losing water; we’re also losing important electrolytes! This loss can disrupt the delicate fluid balance in the brain.
Our brains are smart and often kick into gear with what's called a homeostatic response. Basically, it releases certain chemicals, like cortisol, vasopressin, and neurotransmitters, to try and fix the imbalance. But these shifts in brain chemistry can result in changes to our cognitive performance like our working memory, vigilance, short term memory, visual attention as well as have an impact on our mood.
If sodium levels drop too low, it can throw off the natural balance of fluids in your brain. The extracellular fluid becomes too diluted so extra water is directed to move into the brain cells, which may cause them to swell slightly. This cascade of events then triggers other changes in the brain to counteract the swelling and in these fluctuations and changes- dysfunctions may temporarily occur- resulting in nausea, vomiting, confusion amongst other signs.
Chronically low levels of sodium can cause further issues and damage to the central nervous system, resulting in neurological deficits, fatigue, weakness and even falls and imbalance.
Whilst we are well aware that athletes (especially endurance athletes) are at risk of dehydration and sodium loss, it can actually be quite a common issue in the elderly population, especially those that are hospitalised.
Electrolytes for concussion recovery
This balance in electrolytes becomes even more important when the brain is under stress, such as during recovery from a concussion. Research shows that after a concussion, the brain’s ability to regulate fluid balance and maintain homeostasis is often impaired, while its energy and metabolic demands spike significantly. In this vulnerable state, even mild dehydration can worsen symptoms like fatigue, headaches, brain fog, and poor concentration.
Maintaining adequate hydration and electrolyte levels during this time is critical, not just for replenishing what’s lost, but for supporting the brain’s recovery process. Electrolytes like sodium play a direct role in stabilising cell volume and helping to prevent neurological disruptions caused by brain cell swelling or fluid imbalances. Without this balance, cognitive performance can suffer, a pattern observed even in healthy individuals with mild dehydration, where declines in mood, working memory, and attention have been documented.
In short: after a brain injury like concussion, the stakes of staying properly hydrated, with both water and electrolytes, are even higher. Supporting the body’s internal fluid balance can help protect against secondary symptoms and promote a clearer, more stable path to recovery.
Key ways electrolytes support brain function:
- Sodium and potassium regulate brain cell hydration, ensuring proper fluid balance inside and outside neurons for optimal communication.
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Electrolytes are essential for nerve signal transmission, helping your brain send messages quickly and efficiently.
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They help maintain the electrical gradients across cell membranes, which is crucial for memory, focus, and reaction time.
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Imbalances in electrolytes can impair cognitive processes like concentration, short-term memory, and alertness.
- Low sodium (hyponatremia) can lead to brain cell swelling, which may cause confusion, nausea, fatigue, or even neurological symptoms in more severe cases.
- During brain stress or injury, electrolyte balance is especially important to support recovery and reduce symptoms like headaches, fogginess, and poor concentration.
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Electrolyte loss isn’t just for athletes, older adults and hospitalised patients are also at risk of imbalances that affect brain function.
- Support recovery from head stress like concussions
So, the low down..
While staying hydrated is key, it’s also important to maintain electrolyte balance. That means not just drinking water, but also paying attention to what your body loses, and making sure you're replenishing it properly. Your brain and body will thank you for it.
The salty science:
Giuliani, C., & Peri, A. (2014). Effects of Hyponatremia on the Brain. Journal of Clinical Medicine, 3(4), 1163-1177. https://doi.org/10.3390/jcm3041163
Masento, N. A., Golightly, M., Field, D. T., Butler, L. T., & van Reekum, C. M. (2014). Effects of hydration status on cognitive performance and mood. British Journal of Nutrition, 111(10), 1841–1852. https://doi.org/10.1017/S0007114513004455
Zhang, N., Du, S., Zhang, J., Ma, G. (2019). Effect of dehydration and rehydration on cognitive performance and mood among young adults in Beijing, China: A randomized controlled trial. European Journal of Clinical Nutrition, 73(5), 734–740.
https://doi.org/10.1038/s41430-018-0195-1
Howell, D. R., & Southard, J. (2022). The role of hydration in sport-related concussion recovery: A new frontier. Current Sports Medicine Reports, 21(3), 84–89.
https://doi.org/10.1249/JSR.0000000000000925