Our brains are composed of approximately 70% water and our blood is more than 85% water, which makes plain ol’ water probably the most essential “nutrient” that our brain needs to function properly. In a 2012 study, researchers at the University of Connecticut induced dehydration in healthy young women through either exercise or exercise plus a diuretic and assessed its effects on mood state. Dehydration was found to result in a measurable increase in “total mood disturbance.” A 2018 study published in the World Journal of Psychiatry evaluated anxiety and depression levels of 3,327 Iranian adults that found depression and anxiety levels higher inversely associated with the amount of water the studied individuals drank. A 5% drop in body fluids will cause a 25% to 30% loss of energy in the average person. It is estimated that about 80% of the North American population suffers from energy loss due to minor dehydration. Could your fatigue simply be dehydration? And according to research published in 2013 by the ACSM Health Fitness Journal, even mild dehydration of just a body water loss of 1% (which can occur through routine daily activities) impairs cognitive performance, resulting in poor concentration, decreased reaction time, and short-term memory problems, as well as moodiness and anxiety.
How can water impact our
mental health so strongly?
- Dehydration causes our brain functioning to slow down and reduces energy production in the brain resulting in brain functions shutting down, brain fog, and symptoms of depression. A 2015 study conducted at Loughborough University, found dehydrated volunteers committed a significantly greater number of errors such as lane drifting and late braking in a two-hour driving simulation. Their performance was just as poor as that of people who complete similar tests while at the legal limit for blood alcohol content showing that dehydration reduces concentration and reaction time.
- Dehydration reduces neurotransmitter production by affecting the ability to turn amino acids into neurotransmitters which require sufficient water to carry hormones and nutrients to their destinations. Also since water is required to produce the digestive juices needed for digesting proteins to turn them into the amino acids used as the building blocks of neurotransmitters. The result can be lowered mood, feeling dejected, feeling inadequate, feeling more anxious, feeling irritable, feeling sad, or feeling unmotivated.
- Dehydration stresses the body, resulting in an increase in stress hormone release which negatively impacts production and utilization of neurotransmitters.
- Drinking water creates relaxation in the body by supporting vagal tone, an important counter-act to stress and anxiety.
- Panic attacks, anxiety attacks and dehydration share the symptoms of increased heart rate, headaches, muscle fatigue and weakness, feeling light-headed. The physical experiences of dehydration can prompt a panic attack through the fear that rises as similar symptoms appear.
- We know that chronic pain can result in higher levels of depression as well as feelings of anxiety. Interestingly, dehydration increases pain sensitivity. A 2014 study by Japanese researchers had volunteers immerse an arm in cold water to test their pain sensitivity while having their brains scanned. They reported a lower pain threshold (i.e., they felt pain sooner) when they performed this test in a dehydrated state. These subjective reports were accompanied by increased activity in brain areas involved in the experience of pain.
- Dehydration has also been found to negatively impact memory. In 2010, researchers at Ohio University measured hydration status in a group of 21 older women and also had them complete tests of declarative and working memory. A strong link between hydration status and memory skills was found, with the most dehydrated subjects performing most poorly on the tests.
- Water consumption decreases activity of the sympathetic nervous system (“fight or flight”) by decreasing plasma levels of norepinephrine as found in a 1999 study published in the Lancet. Increased plasma levels and the resulting activation of the HPA axis can be connected to all depressive disorders based on a 2012 study of psychotic depression published in the journal Therapeutic Advances in Psychopharmacology.
And this isn’t even about the research on metabolism and the connection between dehydration and weight gain!
HOW MUCH TO DRINK?
The formula we learned in school was to drink eight 8-oz glasses of water a day. Who drinks water from glasses these days anyway! While this gets us in the general ballpark, new recommendations base the amount on the individual. Aim for drinking between half an ounce and an ounce of water for each pound you weigh, every day. For example, if you weigh 150 pounds, that would be 75 to 150 ounces of water a day. If you’re living in a hot/dry climate, a high altitude (like Colorado), and/or exercise/sweat a lot (cross fitters and hot yoga), you’d be on the higher end of that range; if you’re in a cooler climate and mostly sedentary, you need less. Caffeine and alcohol are dehydrating so you need to up your hydration game if engaging in those drinks. I usually recommend drinking an extra glass/cup of water for each glass of alcohol/cup of coffee.
How can you tell if you’re dehydrated?
- Increased hunger: Hunger and thirst signals come from the same part of the brain. Hunger, when you know you’ve eaten enough, probably means you need to drink some water, not eat more.
- Dryness: Dehydration can be reflected as dryness, including dry, itchy skin, dry mouth, chapped lips, etc. If you pinch the skin on the back of your hand does it immediately lay flat again or slowly join back to your hand?
- Headache: Lack of water facilitates a shortage of oxygen supply to the brain, which can be indicated by a headache.
- Fatigue and weak/cramped muscles: Muscle weakness, spasms, cramping, etc., are common signs of dehydration (though can also be low potassium or magnesium).
- Bad breath: Dehydration causes dry mucous membranes in the mouth, which means you’re not producing enough saliva to help your mouth fight off odorous bacteria.
- Rapid heartbeat, rapid/shallow breathing, and fever can be signals of severe dehydration. Going to the ER and getting IV water infusion could be essential.
- You can verify how hydrated you are based on the color of your urine. If you’re adequately hydrated, your urine will be a very clear/pale yellow color (think Corona beer). If you’re dehydrated, your urine will be a dark yellow or tan color. The darker and more similar to a stout beer color, the worse.
How to boost water consumption:
- Measure your water consumption – don’t refill your water bottle/glass until you’ve finished it and know how many ounces your bottle holds.
- I find it easier to track my water consumption with reusable water bottles than glasses – figure out how many glasses or bottles you need to drink each day and figure out what time of day you should have drank how much.
- Set an alarm to remind you to drink water.
- Start your morning by chugging water. Morning seems to be the only time we can consume a lot of water and still absorb it. If you drink water and hear it sloshing – it is too much water at once and you aren’t absorbing it.
- Always have water with you – carry a water bottle everywhere, keeping it at school, at work, at home, in your car, in your purse.
- Adding lemon, lime or some fruit to water can make it more enjoyable to drink. Some clients have found flavored stevia drops helped them get their water consumption up.