• Roxie Daggett

Mood, Memory & Hydration: Why Drinking Water Keeps You Sharp and Smiling

Updated: Jun 17, 2020

We know that adequate water intake can affect our physical performance, but what about the mental benefits of proper hydration? Read on to learn how life's most basic nutrient can have BIG impacts on your brain health!

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What's Going on in Your Head?

Your brain is the supercomputer for your whole body. This powerful machine not only regulates the beat of your heart and breathing, your ability to see, hear, speak, smell and move, it also helps dictate our moods and preserve our memories throughout our lives.

Eating well certainly helps this critical organ do its demanding jobs optimally. But what about drinking water? Before I set my clients up with any nutritional regime, I always check their hydration status.

This basic nutrient can't be underestimated. Let's find out why -- especially as it pertains to the vital impact on two vulnerable conditions: your mood and your memory.

A Well Watered Mind

Our brains are made up of about 75% water. This basic nutrient keeps our brain cells plump and juicy and helps our neurotransmitters stay in good communication with each other. It also helps transport all those delicious nutrients we eat straight up into our hungry headspace.

In other words, proper hydration means that the vitamin C you get from citrus and berries and the vitamin E you get from nuts and avocados-- two major memory-strengthening vitamins-- are getting absorbed and escorted via water up into your brain tissue for optimal function.

However, when we are dehydrated the flow of nutrients and brain cell integrity-- the shape that keeps everything roomy and comfy for optimal cell function-- become compromised. Studies have shown that when we experience mild dehydration, even as little as 1-2%, our cognitive performance decreases and our moods shift dramatically.

This can happen at any age, but our children, immune compromised friends and family, and elders are most susceptible to dehydration. For kids this often has to do with their smaller size and easier ability to lose water-- especially being so active and busy (plus they don't always replace water when they are thirsty). For immune compromised folks, this can happen for a number of reasons, but a stressed immune system will certainly have higher demands for hydration and electrolytes. For elders dehydration often has to do with lower overall body water content and a decrease in thirst sensations as we age.

For all groups-- and for those of us who are working, stressed and busy, it's important to stay on top of our daily water intake for the benefit of our bodies AND our minds.

Moody, Tired and Stressed?

Studies have shown that mild dehydration-- again only a loss of about 1-2%-- can have significant negative impacts on mood, energy and stress levels of both men, women and children.

In a study done on men in 2011, scientists found that mildly dehydrated men reported significant increases in fatigue and lack of energy along with high tension and anxiety scores, both at rest and during exercise.

A study done on women in 2012 found similar results with demonstrating even greater negative impacts on mood than men. After experiencing mild dehydration, the women reported significant adverse effects on mood and energy along with increases in headaches, difficulty concentrating and negative perceptions of task difficulty. Gee, that sounds familiar!

Lastly, in a review looking at hydration and cognitive function in children in 2006, researchers found that: "significantly higher mood scores for anger, confusion, and fatigue were seen under conditions of mild dehydration" in young adults. I'm sure any parent can attest to this common occurrence after a hard day of playing and not drinking enough fluids!

Possible reasons for these consistent negative findings on mood is that dehydration has been shown to increase stress hormones like cortisol which can make us alert and vigilant, but also edgy and unfocused. Lack of adequate water to the body and brain has also been shown to affect the function of serotonin in our brains-- the neurotransmitter and hormone associated with happiness.

If that doesn't convince us to stay well-hydrated, perhaps we need to consider how hydration is impacting our memory and cognitive function.

Brain Blood Flow in Slow Mo

When we lose fluids, either through urine, feces, sweat or just breathing, and don't replace them it can cause mild dehydration leading to shifts in our body's cell and plasma (blood) volume.

This means less fluid -- less blood flow to the brain. A study done on older folks with urinary incontinence (associated with excess urine loss) showed via brain scanning and other testing loss of blood flow to the frontal lobes of the cerebral cortex. These folks also demonstrated impaired cognitive function, especially as related to time questions. In other words, those with urinary incontinence and low blood flow to the frontal lobes of the brain-- and very likely mild to moderately dehydrated-- had difficulty answering questions like: About what time do you think it is? How long have you been in this building? What date is it? What day of the week is it? What did you do right before you came to see me? What did you eat for breakfast today?

These questions are often called "temporal orientation" or "time orientation" questions. They are often used as part of the screening for cognitive impairment and dementia. Interestingly, some of these are short term memory questions. Studies have shown that short term memory is often the first part of the memory to fade when someone is facing cognitive impairment. No doubt it seems compelling to keep well-hydrated, especially as we age!

Other studies, both animal and human, have also shown an association with dehydration and reduced blood flow to the brain. The studies not only revealed the potential cognitive challenges of "underperfusion" (less blood flow) of the brain, but in the animal study this was also associated with worsened neurological outcomes after stroke. Yikes!

And lest we think any of this dehydration damage is relegated to solely to aging, a study on kids showed lower short term memory scores and poorer performance on verbal tasks in mildly dehydrated children.

Clearly, our brains need water to function optimally at all stages of life!

As a reminder, here are some signs of mild dehydration (1-2% body loss-- our body make-up is about 60% H2O):

  • Dry mouth/tongue/thirst

  • Headaches

  • Fatigue/lethargy

  • Dry skin

  • Muscle weakness

  • Light-headedness/dizziness

  • Lack of focus

  • Cravings

  • Cramps

  • Irritability

  • Anxiety

Just because something is common does not mean it's normal. If you are regularly feeling any of these signs of mild dehydration, it may be time to up your game on this basic nutrient!

Let's talk about how to do it properly!

Drink to Think Better

I mentioned in my Good Morning Gut-Brain Tonic recipe that I usually advise my clients to drink at least half of their body weight (in pounds) in ounces per day. This means that if you weigh 180 pounds you should drink at least 90 ounces of water per day. And possibly more if you live in a dry climate, spend a lot of time outdoors, exercise regularly or heavily, are pregnant or nursing, drink a lot of caffeinated beverages, sodas or juices... or are just extra thirsty.

If you aren't currently drinking anywhere close to that figure, work your way up slowly so as not to overwhelm your system. Consider increasing your daily water intake by 8-12 ounces (one or two more glasses per day) each week so your cells, tissues and organs can adjust to the flow of nutrients pouring in. Remember, it's not just water, but water soluble nutrients-- many vitamins and minerals-- that need adequate water to get where they are going!

Also, it's critical to make sure your water has minerals or electrolytes in it otherwise you risk over-hydrating causing your body to pull minerals out of your cells and tissues. If you have filtered water, especially distilled or reverse osmosis, you can add a pinch of sea salt or a few drops of trace minerals to your glass or bottle. Mineralizing your water helps keep the water in your body and brain!

6 Tips for Staying Hydrated All Day Long

It can be hard to remember, or just plain boring, to drink enough water. Personally, I LOVE drinking water, but I have clients, friends and family who struggle with this tedious habit.

Here are some nifty tips to get you started:

  1. Start your day with a 12-20 ounces of filtered water or try this Good Morning Gut-Brain Tonic to get a head start!

  2. Fill all your glasses and bottles for the entire day and set them out where you can see them (be sure to add a pinch of sea salt or a couple drops of trace minerals to each bottle for electrolyte balance-- especially if you have reverse osmosis or distilled water). Opt for glass or stainless steel bottles like these or these ones so your water stays pure and so you are not exposed to endocrine disrupting plastics. I personally just use large Ball jars and empty fruit juice bottles to drink from!

  3. Add some citrus, fruit, herbs or spices to your glass or bottle to keep things interesting. Check out my 4 Easy Electrolyte Drinks you can make to sip on all day! I love juicing a grapefruit and lime and then topping a 32 ounce jar with filtered water and sipping all afternoon. Take that Arizona summer heat!

  4. Drink away from meals so as not to disrupt digestion. Water can dilute stomach acid which you need to break down all those nutrients. Stop drinking 15 minutes before a meal and try to wait 45 minutes or ideally one hour after meals.

  5. Consider a water app, phone timer or simple chart to remind yourself to go grab your next bottle or refill. True confession: I sometimes use a strip of post-it tape on my bottle and write down my daily water goal (1,2,3,4 refills) and cross off the numbers throughout the day. I know, I know-- #superfreakingnerdy... but effective!!!

  6. Stop drinking a few hours before bedtime if you don't want to be up peeing at night. Personally, I need a small glass of water before bed especially in the hot, southwest summers! Do what you need to do!

Remember, it takes time for your body to experience the benefits of proper, long term hydration. I always say being dehydrated, especially year after year, is like being in a drought. It takes time and diligent watering to restore the terrain to optimal function. Be patient as you replenish your cells, tissues and organs-- including your precious brain-- with this essential and life-giving nutrient. The results will be worth it!

How about you? Do you like drinking water? Hate it? Have any good strategies for staying hydrated? I'd love to hear your thoughts in the comments below!


  1. Armstrong, E., L., Ganio, S., M., Casa, Douglas J., L., … R., H. (2011, December 21). Mild Dehydration Affects Mood in Healthy Young Women. Retrieved from https://academic.oup.com/jn/article/142/2/382/4743487

  2. Danci, K. E., Constant, F., & Rosenberg, I. H. (2006). Hydration and Cognitive Function in Children.Nutrition Reviews,64(10), 457–464. doi: 10.1111/j.1753-4887.2006.tb00176.x. Retrieved from http://saltstick.com/sswp/wp-content/uploads/2017/05/DAnci.2006.NutrtionInClinicalCare.pdf

  3. Ganio, M. S., Armstrong, L. E., Casa, D. J., Mcdermott, B. P., Lee, E. C., Yamamoto, L. M., … Lieberman, H. R. (2011). Mild dehydration impairs cognitive performance and mood of men.British Journal of Nutrition,106(10), 1535–1543. doi: 10.1017/s0007114511002005. Retrieved from https://www.cambridge.org/core/services/aop-cambridge-core/content/view/3388AB36B8DF73E844C9AD19271A75BF/S0007114511002005a.pdf/mild_dehydration_impairs_cognitive_performance_and_mood_of_men.pdf

  4. Griffiths, D. (1998, August 14). Clinical studies of cerebral and urinary tract function in elderly people with urinary incontinence. Retrieved from https://www.sciencedirect.com/science/article/pii/S0166432897001873

  5. Moralez, G., Romero, S. A., Rickards, C. A., Ryan, K. L., Convertino, V. A., Cooke, W. H., … Stewart JM. (2012, June 1). Effects of dehydration on cerebrovascular control during standing after heavy resistance exercise. Retrieved from https://journals.physiology.org/doi/full/10.1152/japplphysiol.01217.2011

  6. Riebl, S. K., & Davy, B. M. (2013, November). The Hydration Equation: Update on Water Balance and Cognitive Performance. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4207053/

  7. Tsai, Yuan-Hsiung, Yang, Jenq-Lin, Lee, Yang, … Chia-Hao. (2018, August 30). Effects of Dehydration on Brain Perfusion and Infarct Core After Acute Middle Cerebral Artery Occlusion in Rats: Evidence From High-Field Magnetic Resonance Imaging. Retrieved from https://www.frontiersin.org/articles/10.3389/fneur.2018.00786/full#B17

About the Author

Roxie Daggett is a Nutritional Therapy Practitioner (NTP) with a virtual practice in Sedona, Arizona. Her passions include studying nutritional research pertaining to memory, brain health, genes and longevity. When she is not geeking out on nutrition she enjoys messing around in the kitchen with old world recipes, reading and hearing stories from elders and farmers about traditional food sourcing, and wandering around the Red Rocks with her heroic husband and Staffordshire bull terrier.

Learn more on her About page and stay in touch by grabbing your FREE BRAIN HEALTH

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