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Hydration for Health: Unraveling the Science of Optimal Hydration

Hydration for Health: Unraveling the Science of Optimal Hydration

Hydration for Health: Unraveling the Science of Optimal Hydration


Hydration isn't merely about quenching thirst - it's an essential aspect of maintaining optimal health and well-being. With today's bustling lifestyles and a keen focus on health optimisation, understanding the science behind hydration has never been more important. This blog post delves into the comprehensive understanding of optimal hydration and its impacts on various aspects of our health, including gut health, brain function, and overall physiological performance.

Hydration 2.0

The standard advice of drinking 8 glasses (2 litres) of water a day might not suffice for everyone. Your hydration needs depend on factors like age, gender, weight, physical activity, climate, and diet.

Research suggests that hydration should be a personalised approach. Some prefer to use apps or wearables that monitor their hydration levels and remind you to drink water. Try experimenting with different amounts and timing to find what makes you feel your best.

Remember, all fluids count towards your hydration - water, herbal tea, fruits and vegetables with high water content, and even your morning coffee. But nothing beats plain water for hydration, and aiming for the majority of your fluid intake to be water is a good rule of thumb.

Biohack Your Hydration

Biohacking is all about making changes to your lifestyle to "hack" your body's biology and feel your best. And when it comes to hydration, there's plenty to hack:

  1. Hydrate First Thing in the Morning: Start your day with a glass of water to rehydrate after a long night's sleep. 
  2. Choose Quality Water: All water isn't created equal. Consider investing in a high-quality water filter that removes contaminants but keeps beneficial minerals. Some biohackers even swear by natural spring water for its purity and mineral content. 
  3. Hydration Boosters: Consider adding natural electrolytes to your water. Coconut water, a natural source of electrolytes, or specific supplements can help, especially during intense physical activity or hot weather.
  4. Mindful Hydration: Develop a mindful drinking habit. Pay attention to your body's subtle signals of thirst and respond in a timely manner.

Hydrating Foods

Boost your hydration by including high-water-content foods in your diet. Cucumbers, courgette, watermelon, and strawberries are over 90% water. Eating these foods can be a fun and tasty way to increase your water intake.

Are Adults Drinking Enough Water?

There's research suggesting that many adults are not drinking enough water and may be chronically mildly dehydrated. However, quantifying this precisely is challenging as hydration needs can vary significantly between individuals and can be influenced by factors such as climate, physical activity, and individual physiology.

One study published in 2013 found that about 75% of Americans likely had a net fluid loss, pointing to chronic dehydration [1]. This figure might not translate directly to other countries or regions with different climates and dietary practices.

According to the CDC's National Health and Nutrition Examination Survey (NHANES) 2005–2010, U.S. adults drank an average of 39 ounces (about 1.1 litres) of water on a given day [2]. For comparison, the National Academies of Sciences, Engineering, and Medicine recommends a daily total water intake (from all beverages and foods) of about 3.7 litres for men and 2.7 litres for women [3].

These statistics suggest that a significant percentage of the adult population might not be reaching optimal hydration levels. However, this doesn't necessarily mean that all these individuals are experiencing negative health effects. Many factors influence hydration needs, and individuals can have different tolerance levels for mild dehydration.

Does Optimal Hydration Differ Between Males & Females?

Optimal hydration does indeed differ between men and women. On average, men are advised to consume about 3.7 litre of water from all beverages and foods each day, while women's recommendations are slightly lower at 2.7 litres per day. This difference can be attributed to the variations in body composition and metabolic needs between men and women [3].

While the fundamental importance of hydration is universal, there are some sex-specific factors that might influence hydration needs. However, it's important to note that these differences are generally nuanced and often depend on other factors such as physical activity level, age, and overall health.

  • Men: Men, on average, have a higher total water percentage in their bodies (approximately 60%) compared to women due to their higher muscle mass. Muscle tissue contains more water than fat tissue. Thus, men might require more water intake to support their metabolic needs [4]. 
  • Women: Women’s hydration needs can vary during different stages of the menstrual cycle due to hormonal fluctuations. For instance, some women may retain more water during certain phases of their menstrual cycle, which can affect their hydration status [5]. Additionally, during pregnancy and lactation, women's hydration needs increase to support the needs of the foetus or breastfeeding.

Regardless of gender, it's essential to listen to your body. If you're thirsty, drink. If you're participating in strenuous exercise or spending time in a hot environment, you'll likely need to increase your fluid intake. In the end, maintaining optimal hydration requires a personalised approach that considers your unique physiological needs and lifestyle factors

The Importance of Hydration and Its Influence on gut Health

Hydration plays a critical role in maintaining a healthy digestive system. Adequate water intake helps ensure that your body can efficiently break down food, absorb nutrients, and eliminate waste. Here are some additional ways hydration can impact your gut:

  1. Water and Digestive Enzymes: Water is a critical component of saliva, which carries enzymes responsible for the early stages of digestion. This process breaks down food into smaller molecules that can be absorbed by the body. Dehydration can lead to a dry mouth, which disrupts this crucial first step in digestion [1].
  2. Water and Nutrient Absorption: Adequate hydration aids in the absorption of nutrients in the gut. Water-soluble vitamins, like vitamin C and the B-vitamins, specifically require water to be absorbed. These vitamins are crucial for energy production, immune function, and overall cell health [1].
  3. Hydration and Bowel Health: Water softens the stool, helps in its passage, and promotes regular bowel movements. This process prevents constipation, which often results from insufficient water intake. Persistent constipation can lead to serious health issues, including haemorrhoids and diverticular disease [6].
  4. Hydration and Gut Microbiota: Emerging research indicates a connection between hydration status and gut microbiota, the collection of beneficial microbes residing in our gut. While research in this area is ongoing, it's thought that adequate hydration may support a healthy balance of these gut microbes, integral to our immune system, mental health, and more [7].

Given the essential role water plays in digestion, nutrient absorption, bowel health, and possibly even the health of our gut microbiota, it's clear that hydration is much more than a simple health tip. It's a crucial component of a biohacked, optimised lifestyle geared towards feeling your absolute best.

Remember to adjust your hydration needs based on your lifestyle, dietary habits, and physical activity, and always listen to your body's thirst signals. Aim for a combination of drinking fluids and consuming water-rich foods throughout the day for the best results.

Next time you take a sip of water, remember - you're not just quenching your thirst. You're contributing to your gut health, aiding your digestion, and supporting your overall well-being. Now that's something to drink to!

Hydration and Brain Health: The Cognitive Connection

Water makes up about 75% of the brain's weight, so it's no surprise that optimal hydration is crucial for brain health. Adequate hydration helps maintain cognitive functions, including attention, executive function, and motor coordination. Dehydration can impair both cognitive performance and mood in young adults [8]. 

Hydration and Brain Health 

  1. Cognition and Performance: Even mild dehydration can impair cognitive performance. A study in young women showed that a fluid loss of 1.36% after exercise led to decreased mood, increased perception of task difficulty, and poorer concentration [9]. 
  2. Mood and Behaviour: Dehydration impacts mood and certain aspects of brain function, such as alertness and concentration. A study conducted on young men found that 1.59% fluid loss negatively affected working memory and increased feelings of anxiety and fatigue [8].
  3. Brain Volume and Function: Dehydration can lead to a reduction in brain tissue volume, affecting cognitive function. This reduction can manifest as temporary brain shrinkage and may impair brain function, similar to the effects of more severe cognitive disorders. Although this is a temporary and reversible condition upon rehydration, chronic dehydration could potentially lead to long-term issues [10].
  4. Attention and Memory: Dehydration can also affect attention span and short-term memory. A review of various studies found that short-term memory and attention can be particularly affected in children and young adults who are mildly dehydrated [11].

To maintain optimal brain function, it's crucial to stay properly hydrated. Drinking adequate water throughout the day and replenishing fluid loss, especially after exercising or during hot weather, can help ensure your brain stays healthy and functions efficiently.

Hydration Supplements for Cognitive Performance

The electrolytes found in many hydration supplements, such as sodium, potassium, and magnesium, also have been linked to brain health.

  1. Sodium plays a role in nerve transmission, which is essential for cognitive function.
  2. Potassium is crucial for maintaining neuronal function, and potassium imbalances have been linked to cognitive impairment.
  3. Magnesium supplementation has been found to improve certain aspects of brain function, including learning and memory. Magnesium is essential for the regulation of neurotransmitters, which send signals throughout the brain and body.

Remember, proper hydration isn't just essential for your body—it's also vital for your brain. So fill up that water bottle and take a step towards boosting your brain health and cognitive performance today!

Recognising Signs of Dehydration

Dehydration can range from mild to severe. Here are some common signs that you might need to boost your hydration:

Mild to Moderate Dehydration:

  • Thirst
  • Dry mouth
  • Tiredness
  • Decreased urine output or darker yellow urine
  • Headaches
  • Dry skin

Severe Dehydration:

  • Very dry skin
  • Feeling dizzy
  • Rapid heartbeat
  • Rapid breathing
  • Sunken eyes
  • Sleepiness, lack of energy, confusion or irritability
  • Fainting

The Role of Electrolytes, Hydration Multipliers, and Hydration Supplements

Electrolytes are crucial for maintaining fluid balance, muscle contraction, and neural activity. Electrolyte supplements can be an effective way to ensure you're getting enough key electrolytes, especially sodium, potassium, and magnesium, which play vital roles in hydration and overall body function. These supplements can help combat electrolyte imbalances, which can happen through excessive sweating, intense exercise, hot weather, and illnesses involving vomiting or diarrhoea [12]. 

Electrolytes play a vital role in maintaining hydration, supporting nerve function, balancing blood pH, and contributing to various other bodily processes. These electrically charged minerals dissolve in water inside our bodies, allowing them to move and carry electrical signals for these functions. Key electrolytes include sodium, potassium, magnesium, calcium, and chloride.

Primary Electrolytes

  • Sodium helps regulate the body's fluid balance by retaining fluids in the body. It supports muscle and nerve function and influences blood pressure [13].
  • Potassium works in conjunction with sodium to regulate the body's water balance, and it helps maintain the nervous system, heart rhythm, and muscle contractions [14].
  • Magnesium is involved in over 300 biochemical reactions in the body, including muscle and nerve function, maintaining heart rhythm, and supporting the immune system [15]. 

While these electrolytes are readily available in a balanced diet, there are situations where an electrolyte supplement can be beneficial:

  1. Intense Physical Activity: During heavy exercise, the body loses electrolytes through sweat, particularly sodium and potassium. Electrolyte supplementation can help replace these losses and improve hydration, especially during prolonged endurance exercises or high-intensity workouts. 
  2. Hot Weather: In hot climates or during summer months, electrolyte needs can increase due to greater sweat loss. Staying adequately hydrated and maintaining electrolyte balance is essential to prevent heat-related illnesses. 
  3. Illness: Conditions like gastroenteritis (stomach flu) or any illness causing vomiting or diarrhoea can lead to significant electrolyte loss. 
  4. Dietary Restrictions or Deficiencies: Those on restrictive diets or with certain nutritional deficiencies may benefit from electrolyte supplements to help meet their needs.

It's important to consult a healthcare professional before starting an electrolyte supplement, especially for those with kidney diseases or individuals taking certain medications like diuretics, ACE inhibitors, or angiotensin receptor blockers.

Remember, while electrolyte supplements can be beneficial in certain circumstances, they are not a substitute for a balanced, nutrient-dense diet. Adequate hydration combined with a diet rich in fruits, vegetables, whole grains, and lean proteins is the best way to ensure your electrolyte needs are met for optimal health and wellbeing.

You can read more about electrolytes in this WellEasy blog. 

Hydration and Fasting: A Balancing Act

When you're fasting, hydration becomes even more crucial. The absence of food means your body isn't receiving its usual water content from foods, increasing the importance of drinking enough water. Moreover, electrolyte balance can be disturbed during fasting, particularly longer fasting periods, making electrolyte supplementation potentially beneficial [16].

  1. Hydration: During fasting, you're not taking in any food or, in some types of fasting, any fluids. This can potentially lead to dehydration, especially if the fasting period is extended. Drinking sufficient amounts of water is crucial during the eating periods in intermittent fasting, or, if allowed, throughout the day in other types of fasting [17]. 
  2. Electrolytes: During fasting, the body can also lose electrolytes, especially if you're still engaging in physical activity. Maintaining electrolyte balance is critical for preventing symptoms such as dizziness, headaches, or fatigue, which can be exacerbated during a fast. Sodium, potassium, and magnesium are key electrolytes that need to be replenished if allowed during a fast.
  3. Supplements: If the type of fast permits, using an electrolyte supplement without added sugars or calories can be beneficial for maintaining electrolyte balance. These supplements can provide a mix of essential electrolytes, including sodium, potassium, and magnesium. Always remember to check the ingredients list and consult with a healthcare professional before incorporating any supplements into your routine.
  4. Breaking the Fast: Hydrating and replenishing electrolytes should also be a priority when breaking a fast. Consuming a balanced meal with plenty of fluids can help restore any potential deficits. Foods rich in electrolytes such as fruits, vegetables, legumes, and lean proteins are great options.

Why is Electrolyte Supplementation Popular in the Keto Community?

The ketogenic diet can have a unique impact on the body's electrolyte balance due to its high-fat, low-carb nature. The initial phase of this diet often comes with what is called the "keto flu," the symptoms of which can partly be attributed to electrolyte imbalances [18]. Therefore, electrolyte supplements are often recommended to maintain balance and mitigate these symptoms.

Here are some reasons why people on a ketogenic diet might benefit from electrolyte supplements:

  1. Keto Flu: When you first start a ketogenic diet, your body may go through a transitional period often referred to as the "keto flu." Symptoms can include headache, fatigue, nausea, dizziness, and irritability. These symptoms can partly be attributed to electrolyte imbalances, as your body adjusts to burning fat for energy instead of carbs [18].
  2. Diuretic Effect: A ketogenic diet can have a diuretic effect, causing increased urine output. This happens because glycogen, the stored form of glucose in the body, binds with water. When you restrict carbs on a keto diet, your body burns through its glycogen stores, and the water attached to the glycogen gets excreted in the urine. As a result, you lose not only water but also electrolytes [19].
  3. Decreased Insulin Levels: Lowering carbohydrate intake on a keto diet leads to decreased insulin levels. Insulin helps regulate sodium reabsorption in the kidneys. When insulin levels are lower, the kidneys excrete more sodium, which can lead to an electrolyte imbalance if not properly managed.


Optimal hydration is a crucial aspect of maintaining overall health, cognitive performance, and gut health. With adequate knowledge and the right strategies, individuals can effectively optimise their hydration status for better health outcomes. Always remember to consult a healthcare provider before starting any new supplement regimen.

If you want to explore WellEasy's hydration-related products, click here

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