Understanding cognitive performance

Written by Mark Payne, Melbourne Functional Medicine

The pillars of cognitive function

Cognitive performance is a multifaceted concept, encompassing various aspects of brain function that are important for carrying out our daily activities, learning, problem-solving, and decision-making.

These processes involve a complex interaction between different areas of the brain responsible for memory (short-term working memory, and long-term stored memory), attention and focus (concentration), processing speed (how fast our brain processes information), problem-solving, and decision-making (the analytical and critical thinking functions of the brain).

The ability of our brain to efficiently carry out these tasks in an integrated way depends on the health of brain tissues, which also involves hydration.

Lifestyle and cognitive health

The way we live our lives – what we eat, how much we move, the quality of our sleep, and how we manage stress – plays a significant role in determining our cognitive health. Each of these lifestyle factors contributes to the overall functioning of our brain, affecting everything from our memory and attention span to our problem-solving abilities and decision-making skills.

The science of hydration and brain function. 

Hydration: The brain's fuel

Hydration plays a pivotal role in maintaining optimal brain function. The brain, composed of about 75% water, relies heavily on hydration for its various critical functions. 

Brain hydration mechanics

• Water as a medium for nutrient transport: Water in the brain acts as a medium for the transport of essential nutrients to brain cells. It facilitates the movement of electrolytes, which are crucial for nerve function, and helps in delivering glucose, the brain's primary energy source.
• Waste removal: The brain generates metabolic waste during its normal functioning, which needs to be efficiently removed. Water is key in this process, helping to flush out toxins and waste products, including beta-amyloid, which has been linked to Alzheimer's disease.
• Regulating brain chemistry: Water is essential for maintaining the balance of neurotransmitters and hormones that significantly influence mood, cognition, and overall brain health. 

Neurological effects of hydration

• Impact on neuron activity: Neurons, the brain's functional units, require a delicate balance of water and various other elements to function correctly. Proper hydration ensures that neurons can fire and communicate effectively, which is crucial for cognitive processes such as memory, attention, and problem-solving.

• Brain volume and hydration: Dehydration can lead to a reduction in brain volume, affecting its structure and function. Adequate hydration helps maintain brain volume and, consequently, its proper functioning.

• Hydration and cognitive performance: Studies have shown that even mild dehydration can impair cognitive functions, including concentration, alertness, and short-term memory. In fact being dehydrated by just 2% impairs performance in tasks that require attention, psychomotor, and immediate memory skills, as well as assessment of the subjective state.

The consequences of dehydration

Dehydration can have significant adverse effects on cognitive function and overall brain health, both in the short and long term.

Cognitive symptoms

• Impaired concentration and attention: Lack of adequate hydration can lead to decreased attention span and difficulty in maintaining focus. This can affect productivity and the ability to perform tasks that require sustained concentration.
• Memory: Dehydration can negatively impact both short-term and long-term memory. It can hinder the ability to store new information and retrieve existing information.
• Mood fluctuations: Dehydration can lead to irritability, anxiety, and fatigue, affecting overall mood and mental well-being.

Long-term impacts

• Chronic dehydration and cognitive decline: Prolonged dehydration can contribute to long-term issues in brain function. It may increase the risk of developing cognitive disorders such as dementia.
• Brain shrinkage and ageing: Chronic dehydration over time can lead to greater shrinkage of the brain, which is a natural part of ageing but can be exacerbated by inadequate hydration.

Preventative measures 

Regular intake of fluids, especially water, is crucial in preventing the negative effects of dehydration. It's important to recognise the signs of dehydration, such as thirst, reduced urine output, dark urine, fatigue, and dizziness, and to hydrate accordingly.

Electrolytes and their role in cognitive function 

Electrolytes: The brain's spark

Electrolytes are minerals in the body that carry an electrical charge and are essential for a myriad of bodily functions, including several critical aspects of brain health and cognitive performance.

Key electrolytes and brain health

• Sodium: Sodium 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: Potassium is another vital electrolyte for cognitive function. It 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: Magnesium 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. Low magnesium levels have been linked to a range of neurological and psychiatric disorders, including migraines, depression, and epilepsy.
• Calcium: Calcium is critical for nerve function. Calcium enters the nerve cell to stimulate the release of the neurotransmitters that propagate the signal along the nerve. Calcium is closely regulated by the body, but an imbalance of other electrolytes can impair the function of calcium. 

 Electrolyte balance and brain signalling

• Maintaining Electrical Signals: Electrolytes are essential for the maintenance of the electrical signals in the brain. These signals are the basis of all brain activities, from basic reflexes to complex cognitive functions like learning and memory.
• Role in Neurotransmitter Release: Electrolytes, particularly calcium, play a significant role in the release of neurotransmitters. These chemical messengers are crucial for transmitting signals between neurons, affecting everything from muscle contractions to mood and cognition.
• Influence on Brain Plasticity: Electrolytes also influence brain plasticity, the brain's ability to change and adapt as a result of experience. This is crucial for learning new information, forming memories, and recovering from brain injuries.

 The impact of imbalance

An imbalance in electrolytes can have profound effects on cognitive function and overall brain health. 

Symptoms of electrolyte imbalance 

• Cognitive symptoms: Common signs of electrolyte imbalance include confusion, difficulty concentrating, memory problems, and in severe cases, seizures. These symptoms occur because electrolytes are crucial for brain function and even small imbalances can disrupt the delicate balance needed for neurons to communicate effectively.
• Physical symptoms: Besides cognitive symptoms, physical signs like muscle weakness, twitching, fatigue, and headaches can also indicate an electrolyte imbalance.
• Mood and behaviour changes: Electrolyte imbalances can affect mood and behaviour, potentially leading to increased anxiety, depression, and irritability. 

Managing electrolyte levels

• Balanced diet: A balanced diet is key to maintaining optimal electrolyte levels. Foods rich in potassium, magnesium, and sodium, such as bananas, avocados, nuts, seeds, and leafy greens, should be included in the diet.
• Hydration: Proper hydration is crucial for maintaining electrolyte balance. Drinking sufficient water without over-hydrating is essential, but in cases of excessive sweating, illness, or during intense physical activity, electrolyte-rich drinks may be necessary.
• Supplementation: In some cases, especially where diet and hydration are not sufficient to correct imbalances, supplements may be necessary. However, it's important to consult with a healthcare provider before starting any supplementation, as excessive intake of electrolytes can also lead to imbalances and health issues.

Electrolytes are fundamental to brain health and cognitive function. Maintaining a balance of these key minerals through a healthy diet, adequate hydration, and, if necessary, supplementation, is crucial for optimal brain function and overall well-being. 

Practical strategies for optimal hydration 

Building a hydration habit

Developing a habit of regular hydration is crucial for maintaining cognitive function and overall health. However, staying adequately hydrated is a challenge for many. Here are some strategies to help build a consistent hydration habit.

Daily Hydration Goals 

• Assessing individual needs: The amount of water needed can vary greatly depending on factors like body weight, climate, and levels of physical activity. A general guideline is to drink at least 8-10 cups (about 2 litres) of water per day, but this can vary. For instance, athletes or individuals in hot climates may need more.
• Setting realistic goals: Start by setting achievable hydration goals. If you're not used to drinking a lot of water, gradually increase your intake instead of drastically changing your routine.
• Incorporating hydrating foods: Remember that hydration doesn’t come solely from water. Foods like cucumbers, watermelon, oranges, and strawberries are high in water content and can contribute to overall fluid intake.

Hydration Tracking and Reminders

• Using technology: There are numerous apps available that can track your water intake and remind you to drink water throughout the day. These can be particularly useful for those who have busy schedules or tend to forget to hydrate.
• Physical reminders: Keeping a water bottle at your desk, in your bag, or in areas where you spend a lot of time can serve as a physical reminder to drink water. Opt for a marked water bottle to keep track of how much you’re drinking.
• Building it into your routine: Tie your drinking habits to daily activities. For example, drink a glass of water after every bathroom break, or start each meal with a glass of water. This can help make hydration a more automatic part of your routine.

Maintaining electrolyte balance for cognitive health

Supplementing electrolytes

While a balanced diet along with high quality water with a high mineral content is the best way to maintain electrolyte levels, there are situations where supplementation might be necessary.

 When to supplement 

• Intense physical activity: Athletes or those engaging in long-duration or high-intensity workouts may lose significant electrolytes through sweat and may require supplementation. Electrolytes pre, intra or post exercise can see an increase in performance and recovery. A great starting point for many is taken 20 minutes prior to exercise. 

• Health conditions: Certain health conditions, such as kidney disorders, Postural Orthostatic Tachycardia Syndrome (POTS) or digestive issues, can affect electrolyte balance, making supplements necessary.
• Extreme weather conditions: In very hot climates, where sweating is excessive, or in cases of prolonged exposure to heat, electrolyte supplements can help prevent dehydration and imbalance.

• Modern lifestyle factors: In todays world there are many common daily factors that can lead to dehydrated and electrolyte loss. Simple things such and coffee and alcohol can lead to a 1/2tsp sodium loss per glass. Other factors include sitting in air conditioned/heated room all day, some medicines and even sleeping can cause sodium loss through perspiration and night sweats. 

Choosing the right supplements

• Quality and Ingredients: Look for supplements that are free from unnecessary additives and sugars. Check the ingredient list to ensure it contains the electrolytes you need in high quality forms. Ingredients can come in a wide range of forms, with some better than others and each with their own pros and cons. For example, magnesium can be found in dozens of different forms which all range in quality resulting in different rates of absorption and potential side effects. Sodium can be sourced from a wide range of salts with some containing heavy metals, microplastics and even exposure to radiation. 
• Form: Electrolyte supplements come in various forms, including tablets, powders, and liquids. Choose a form that suits your lifestyle and preference.
• Dosage: It’s important to follow the recommended dosage on the supplement or as advised by a healthcare professional. Over-supplementation can lead to imbalances and health issues.
• Consultation with healthcare providers: Before starting any supplement regimen, especially if you have health conditions or are on medication, consult with a healthcare provider.

 While a balanced diet is the best source of electrolytes, supplements can be beneficial in certain situations. It’s important to choose high-quality supplements and use them according to guidelines to maintain optimal electrolyte balance and support cognitive health.

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