Whether you’ve been struggling to focus at work, feeling extra forgetful or feeling the 3 pm brain fog come on, hydration might just be the missing piece. You may not need another coffee or a Nootropic blend to get you fired up and working; something as simple as water plus high-quality salt may be the solution.

To understand why hydration plays such a powerful role in mental sharpness, let’s look at how it directly affects your brain and what happens when even small imbalances set in.

Hydration and brain function

Your brain is made up of about 75% water, so even mild dehydration can impact how it functions.

Research shows that losing as little as 1% of total hydration can impair:

• Cognitive performance
• Memory recall
• Concentration
• Mood stability

Left untreated, dehydration can contribute to brain fog, headaches, migraines, and even chronic mood disturbances.

Electrolytes – sodium, potassium, and magnesium – are essential here. They keep electrical signalling in your brain and nervous system running smoothly, helping you stay mentally sharp.

Staying in the right hydration zone is not just a matter of drinking more water, it is hitting the sweet spot (or as we call it, the “salty spot”) between dehydration and overhydration.

How to tell if you’re hydrated

There are a few simple signs that tell you whether you’re in a healthy hydration zone:

1. Consistent energy levels: Your energy levels are consistent throughout the day, without any dramatic peaks or troughs
2. Natural thirst cues: You’ll naturally reach for water + electrolytes when you need them, not feeling an overwhelming thirst response. If you’re having to force yourself to drink water, then you don’t need any more. Listen to your body
3. Clearer thinking and memory: Mentally, you feel sharp, your memory and recall are on point, and you’re flowing
4. Urine colour: When your urine is a pale or light yellow colour. Clear urine can be a sign of overhydration, and dark urine is a sign that you need water + electrolytes in a hurry
5. Sweating balance during exercise: During sustained physical exercise, you’re sweating, not too much, and not too little

The benefits of staying in the hydration zone

Staying in the right hydration zone doesn’t just quench your thirst; it directly influences how your brain functions, your energy throughout the day, your mood, and even how your body responds to stress. Let’s take a closer look at some of these benefits.

Mental Clarity

Hydration plays a crucial role in maintaining optimal neurotransmitter function. When you’re properly hydrated, your brain can efficiently send and receive messages, leading to sharper thinking, better decision-making, and improved problem-solving abilities.

Energy Levels

Dehydration can leave you feeling sluggish and fatigued, making it harder to stay focused, energised and on task. By staying hydrated, you can help sustain regular energy levels throughout the day, allowing you to remain productive and kick some goals.

Mood Management

Believe it or not, hydration can also affect your mood. Research suggests that even mild dehydration can negatively impact mood and increase feelings of tension and anxiety.

Dehydration, when your body loses more fluid than it takes in, results in clear distress signals like thirst, dry mouth, darker urine, fatigue, dizziness, and reduced exercise performance. On a cellular level, low fluid and electrolyte levels trigger hormonal systems like the renin-angiotensin-aldosterone system (RAAS) and the release of antidiuretic hormone (ADH) to conserve water. This has been shown to impair cognitive function, decrease recovery time, and stress the cardiovascular system.

The renin-angiotensin-aldosterone system (RAAS) is the body’s hormonal network that regulates blood pressure, fluid balance, and electrolyte levels. When your high-quality salt or electrolyte intake is low, the kidneys release renin, triggering a cascade that produces aldosterone, which signals the kidneys to retain sodium and water, raising blood volume and pressure.

Stress Levels

We’ve just touched on the RAAS system. When you’re not including a high-quality salt in your diet regularly, the body activates the RAAS and also increases cortisol production, the main stress hormone. This reaction is intended to help conserve sodium and maintain blood pressure.

This happens because low sodium levels are a red flag signal to the body that something is wrong. The adrenal glands then ramp up both aldosterone to help hold onto sodium and cortisol for the same reason.

Over time, chronically low salt intake can keep cortisol elevated, which may contribute to fatigue, poor recovery, impaired thyroid function, and other stress-related effects. This is where expert guidance makes a difference. At Melbourne Functional Medicine, functional testing and personalised assessments can reveal whether electrolyte or stress hormone imbalances are impacting your health, and provide a clear game plan to get you back in balance.

What true hydration looks like

Whilst plain water is a crucial component of hydration, it’s only one part of the hydration equation. The key minerals sodium, potassium, and magnesium + water work together to:

• Maintain brain electrical activity (sodium)
• Sustain energy and nerve transmission (potassium)
• Support neurotransmitters and protect against stress (magnesium)

Together with water, these minerals, in the right ratio, create what we call true hydration.

So what about ratios?
Electrolytes don’t work in isolation – it’s the balance between them that drives true hydration. Sodium generally needs to be present in the greatest proportion to maintain fluid balance and nerve signalling, while potassium supports sodium in energising cells, and magnesium regulates the sodium–potassium pump itself. Sodii is formulated around this principle, using a ratio of roughly 5 parts sodium : 1 part potassium. And a ratio of 3 part potassium and :1 part magnesium. While individual needs vary with sweat loss, diet, and physiology, the key principle is clear: sodium leads, with potassium and magnesium in smaller but essential supporting roles to fine-tune hydration and stress resilience.

While water sets the foundation, it’s these electrolytes that fine-tune how your brain and body function. Each mineral has a distinct role in keeping you energised, focused, and resilient under stress.

Let’s take a closer look at sodium, potassium, and magnesium and why they’re non-negotiable for true hydration.

Sodium @ 1000 mg plays a pivotal role in brain health. It is crucial for the generation and transmission of electrical signals in the brain and nerves. These electrical signals are necessary for thought processes, memory recall, and muscle contractions. An imbalance in sodium levels can significantly impact brain function, leading to symptoms like confusion, dizziness, and in severe cases, seizures.

Potassium @ 210 mg works closely with sodium to maintain electrical gradients across cell membranes, a process essential for nerve signal transmission. Adequate potassium levels are necessary for sustained brain energy, and deficiencies can lead to fatigue, brain fog, and decreased cognitive function.

Magnesium @ 70mg is key for brain health, involved in over 300 enzymatic reactions in the body, many of which benefit the brain. It helps regulate neurotransmitters, which send messages throughout the brain and body, and plays a role in protecting the brain from stress and potentially harmful substances.

Where to from here?

True hydration isn’t about chugging litres of plain water – it’s about tuning into your body’s signals and giving it the right mix of water and electrolytes. That balance keeps your brain sharp, your energy steady, and your stress response resilient.

If you’re curious to experiment beyond water alone, try adding a clean electrolyte source to your routine and notice the difference in clarity, focus, and recovery. Sodii – made from mineral-rich ancient lake salt in Western Australia and balanced with potassium and magnesium – was designed with exactly this in mind.

You can explore Sodii here with 15% off using code MFM15, or pick some up next time you’re in the clinic at 186 Buckhurst Street, South Melbourne.

However you choose to hydrate, aim for the “salty spot”, not too much, not too little, and let your body do the rest.