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Fluid and electrolyte imbalance: A science-based guide

From the desk of Robb Wolf

<p>When it comes to hydration, most people don’t think about preventing fluid and electrolyte imbalances. They merely think about drinking <a href="https://drinklmnt.com/blogs/health/how-much-water-should-you-drink-a-day-a-science-based-guide-to-hydration">enough</a> water.</p><p>This message has been drilled into our minds since childhood. <em>To stay healthy, drink an 8 oz glass of water, 8 times per day.</em> The problem is, there never was any science supporting this 8×8 rule. The real origin of this flaky myth is <a href="https://www.med.umich.edu/1libr/Gyn/ObgynClinic/8GlassesWaterMyth.pdf" target="_blank" rel="noreferrer noopener">fairly pedestrian</a>, and in fact the science indicates that drinking to thirst is <a href="https://pubmed.ncbi.nlm.nih.gov/12376390/">sufficient</a> in most circumstances.</p><p>In actuality, drinking too much plain water can dilute blood sodium, sometimes to dangerously low levels. The clearest example of this is the unfortunate marathon runners who <a href="https://cjasn.asnjournals.org/content/2/1/151" target="_blank" rel="noreferrer noopener">experience</a> confusion, light sensitivity, and even seizures at the finish line. These aren’t symptoms of fatigue, or even dehydration – they’re symptoms of <em><a href="https://drinklmnt.com/blogs/health/can-you-drink-too-much-water" target="_blank" rel="noreferrer noopener">overhydration</a></em>.</p><p>Specifically, they’re indicative of exercise-associated <a rel="noreferrer noopener" href="https://drinklmnt.com/blogs/health/hyponatremia" target="_blank">hyponatremia</a>. While hyponatremia is an electrolyte imbalance, it’s often treated as dehydration because the symptoms look similar. Yet drinking more water only <a rel="noreferrer noopener" href="https://pubmed.ncbi.nlm.nih.gov/10091501/" target="_blank">worsens</a> the condition. This isn’t just affecting elite athletes. Proper hydration can help <em>all</em> of us feel and perform our best, and that means dialing in fluid balance – so let’s start there.</p><h2><b>What Is Fluid Balance?</b></h2><p><span style="font-weight: 400">Fluid balance </span><a href="https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC5760509/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">refers</span></a><span style="font-weight: 400"> to the distribution of fluids in your blood, organs, and other tissues. Proper fluid balance:</span></p><ul><li><span style="font-weight: 400">Keeps your blood flowing smoothly through your blood vessels</span></li><li><span style="font-weight: 400">Keeps your brain floating in cerebrospinal fluid</span></li><li><span style="font-weight: 400">Keeps your skin moist and supple</span></li><li><span style="font-weight: 400">Helps you cool yourself with sweat</span></li><li><span style="font-weight: 400">Keeps your eyes lubricated with tears</span>&nbsp;</li></ul><p><span style="font-weight: 400">Maintaining proper fluid balance is the goal of healthy hydration, not just preventing </span><a href="https://drinklmnt.com/blogs/health/dehydration-causes-and-symptoms" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">dehydration</span></a>.&nbsp;</p><p><span style="font-weight: 400">In most cases, your body handles mild disruptions like a champ. Even if you’re not thirsty, one extra glass of water won’t kill you. Your brain just suppresses antidiuretic hormone (ADH) and you pee out the excess.</span></p><p><span style="font-weight: 400">And if you consume too much </span><a href="https://drinklmnt.com/blogs/health/is-sodium-good-or-bad-for-you" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">sodium</span></a><span style="font-weight: 400"> (especially without liquids), your hypothalamus responds by making you feel thirsty. Then you drink something and fluid balance gets restored.</span></p><p><span style="font-weight: 400">Let’s talk about what affects fluid balance now. Then you’ll have a better idea of </span><a href="https://drinklmnt.com/blogs/health/how-to-stay-hydrated" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">how to stay hydrated</span></a><span style="font-weight: 400">.</span></p><h2><b>What Affects Fluid Balance?</b></h2><p><span style="font-weight: 400">Your fluid balance system is designed to keep your body running like a German automobile. Some parts of this system (like water and </span><a href="https://drinklmnt.com/blogs/health/what-are-electrolytes-and-why-are-they-important" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">electrolytes</span></a><span style="font-weight: 400">) are under your control, while others are not. I’ll start with the involuntary stuff.</span></p><h3><b>#1: Brain, hormones, and kidneys</b></h3><p><span style="font-weight: 400">Most fluid balancing happens below the threshold of conscious awareness. The main players are:</span></p><ul><li><span style="font-weight: 400">Your brain (especially the hypothalamus)</span></li><li><span style="font-weight: 400">Hormones (ADH, aldosterone, renin, angiotensin, etc.)</span></li><li><span style="font-weight: 400">Your kidneys</span></li></ul><p><span style="font-weight: 400">Your brain constantly monitors your blood osmolality (blood electrolyte concentration) and blood volume. When these become imbalanced, there are several ways your brain may restore order. It can play with ADH to retain or expel more fluids, play with aldosterone (secreted by the kidneys) to retain or expel more sodium, and trigger thirst. And all of those are just for starters.</span></p><p><span style="font-weight: 400">The kidneys are the workhorse in this system. They do the dirty work—absorbing and expelling electrolytes and fluids to keep everything in balance.</span></p><p><span style="font-weight: 400">Most of the time, this system works fine. But kidney failure, heart failure, drugs, illness, and unbalanced water and electrolyte intake are capable of disrupting it.</span></p><h3><b>#2: Water intake</b></h3><p><span style="font-weight: 400">You never see an animal over-hydrating. They only drink when thirsty. That’s because thirst is a simple, effective indication that we need water. It’s incredibly good at preventing dehydration AND overhydration.</span></p><p><span style="font-weight: 400">Your hypothalamus is the primary organ responsible for managing that thirsty feeling. Unless you have a condition that affects your ability to experience this sensation, I highly recommend listening to it.</span></p><p><span style="font-weight: 400">Still, many people listen to another part of their brain: the part that’s been repeatedly told well-meaning, nonetheless </span><a href="https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC4212586/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">bogus hydration advice</span></a><span style="font-weight: 400">. This part, untethered from physical cues, believes that more water is always better.</span></p><p><span style="font-weight: 400">But too much plain water overwhelms the </span><a href="https://drinklmnt.com/blogs/health/what-electrolytes-do-for-you" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">fluid balance system</span></a><span style="font-weight: 400">, causes sodium levels to plummet, and leads to symptoms we don’t want. That’s why we can’t neglect electrolytes.</span></p><h3><b>#3: Electrolyte status</b></h3><p><span style="font-weight: 400">Drinking water is just one instrument in the fluid balancing symphony. You also have your hypothalamus, your kidneys, and a slew of hormones and electrolytes.</span></p><p><span style="font-weight: 400">Electrolytes are charged minerals. They conduct electricity to power your nervous system, structure your skeleton, and regulate fluid balance.</span></p><p><span style="font-weight: 400">Electrolytes (especially sodium and </span><a href="https://drinklmnt.com/blogs/health/potassium-benefits-and-best-sources#:~:text=As%20an%20aside%2C%20I%20use,heart%20failure%2C%20and%20liver%20disease." target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">potassium</span></a><span style="font-weight: 400">) are part of the feedback loop that reports hydration status to your brain. Your body and brain are also ensuring you have enough electrolytes in the blood.</span></p><p><span style="font-weight: 400">If you don’t, it’s red alert. Your bones get ransacked to normalize serum levels. That’s why most electrolyte deficiencies—sodium deficiency, potassium deficiency, magnesium deficiency, and calcium deficiency—are correlated with osteoporosis.[</span><a href="https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC6140170/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">*</span></a><span style="font-weight: 400">][</span><a href="https://pubmed.ncbi.nlm.nih.gov/32042374/#:~:text=Daily%20potassium%20intake%20was%20significantly,risk%20of%20osteoporosis%20in%20men." target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">*</span></a><span style="font-weight: 400">][</span><a href="https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC3775240/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">*</span></a><span style="font-weight: 400">][</span><a href="https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">*</span></a>]</p><p><span style="font-weight: 400">When I talk about an electrolyte deficiency, I’m talking about suboptimal dietary intakes of a given electrolyte. Low dietary intakes alone won’t cause a true electrolyte imbalance, but they </span><i><span style="font-weight: 400">will </span></i><span style="font-weight: 400">increase the risk.</span></p><h2><b>What Is an Electrolyte Imbalance?</b></h2><p><span style="font-weight: 400">An electrolyte imbalance is when blood levels of a given electrolyte get too low or too high. If the imbalance is severe enough, it may require medical attention.</span></p><p><span style="font-weight: 400">Here are the medical terms for the various electrolyte imbalances:</span></p><ul><li><span style="font-weight: 400">Hyponatremia (</span><a href="https://drinklmnt.com/blogs/health/hyponatremia" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">low serum sodium</span></a><span style="font-weight: 400">) and hypernatremia (high serum sodium)</span></li><li><span style="font-weight: 400">Hypokalemia (</span><a href="https://drinklmnt.com/blogs/health/low-potassium-symptoms-and-best-sources" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">low serum potassium</span></a><span style="font-weight: 400">) and hyperkalemia (high serum potassium)</span></li><li><span style="font-weight: 400">Hypomagnesemia (</span><a href="http://drinklmnt.com/blogs/health/hypomagnesemia" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">low serum magnesium</span></a><span style="font-weight: 400">) and hypermagnesemia (high serum magnesium)</span></li><li><span style="font-weight: 400">Hypocalcemia (</span><a href="http://drinklmnt.com/blogs/health/hypercalcemia-and-hypocalcemia" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">low serum calcium)</span></a><span style="font-weight: 400"> and hypercalcemia (</span><a href="http://drinklmnt.com/blogs/health/hypercalcemia-and-hypocalcemia" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">high serum calcium</span></a><span style="font-weight: 400">)</span></li><li><span style="font-weight: 400">Hypophosphatemia (low serum phosphate) and hyperphosphatemia (high serum phosphate)</span></li></ul><p>&nbsp;<span style="font-weight: 400">The main </span><a href="https://drinklmnt.com/blogs/health/electrolyte-imbalance-or-deficiency" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">causes of electrolyte imbalance</span></a><span style="font-weight: 400"> include:</span></p><ul><li><a href="https://drinklmnt.com/blogs/health/how-much-water-should-you-drink-a-day-a-science-based-guide-to-hydration" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">Overhydration with plain water</span></a><span style="font-weight: 400"> (dilutes blood sodium levels)</span></li><li><span style="font-weight: 400">Vomiting or diarrhea (both deplete potassium levels)</span></li><li><span style="font-weight: 400">Heart or kidney failure</span></li><li><span style="font-weight: 400">Medications (diuretics, laxatives, and others)</span></li><li><span style="font-weight: 400">Excessive </span><a href="https://drinklmnt.com/blogs/health/what-causes-hangovers-and-what-to-do-about-them" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">alcohol usage</span></a></li><li><span style="font-weight: 400">Refeeding syndrome</span></li><li><span style="font-weight: 400">Vitamin D deficiency (can disrupt calcium levels)</span></li></ul><p><span style="font-weight: 400">You’ll notice that poor electrolyte intake isn&#8217;t on the list. Remember: if you don’t consume enough electrolytes, your body will pull them from your skeleton. Serum levels are </span><i><span style="font-weight: 400">that</span></i><span style="font-weight: 400"> critical.</span></p><h2><b>Why I Worry About Hyponatremia</b>&nbsp;</h2><p><span style="font-weight: 400">Of all the electrolyte imbalances, I worry most about </span><a href="https://drinklmnt.com/blogs/health/hyponatremia" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">hyponatremia</span></a><span style="font-weight: 400">. Not only is it dangerous, but it’s a direct consequence of poor hydration habits.</span></p><p><span style="font-weight: 400">Poor hydration habits are rampant. People drink water beyond the dictates of thirst much more often than you may think. It’s not their fault, of course. We’ve been taught to believe that it’s a wise and healthy practice. But even a few extra glasses of water could be harmful. Even mild hyponatremia can cause fatigue, low energy, malaise, </span><a href="https://drinklmnt.com/blogs/health/what-causes-muscle-cramps" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">muscle cramps</span></a><span style="font-weight: 400">, irritability, and weakness.</span></p><p><span style="font-weight: 400">Severe hyponatremia is where things truly become scary. Confusion, seizures, brain damage, light sensitivity, brain swelling, and sometimes even death can occur. Many elite athletes have </span><a href="https://cjasn.asnjournals.org/content/2/1/151" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">perished</span></a><span style="font-weight: 400"> from this condition.</span></p><p><span style="font-weight: 400">Just think how a marathon course is set up. Watering stations every couple of miles. Should we be surprised that so many endurance athletes <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5334560/" target="_blank" rel="noreferrer noopener">develop</a></span> exercise-associated<span style="font-weight: 400"> hyponatremia?</span> <span style="font-weight: 400">The idea is to prevent dehydration (net water loss from the body). But optimizing to prevent dehydration is misguided because:</span> </p><ul><li><span style="font-weight: 400">There are </span><a href="https://www.mdalert.com/article/brief-review-of-the-literature-on-hyponatremia-death-and-injury-in-endurance-athletes" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">no sports-related deaths</span></a><span style="font-weight: 400"> from dehydration in all the medical literature.</span></li><li><span style="font-weight: 400">There are </span><a href="https://cjasn.asnjournals.org/content/2/1/151" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">many</span></a><span style="font-weight: 400"> reported deaths from low serum sodium.</span> <span style="font-weight: 400">Aggressively hydrating with plain water increases the risk of hyponatremia</span> </li></ul><p><span style="font-weight: 400">Here’s the deal. Humans are meant to become slightly dehydrated when we sweat. It’s biologically normal.</span> <span style="font-weight: 400">What’s not normal is aggressive fluid replacement. That’s how you cause an electrolyte imbalance — let’s talk about preventing them now.</span></p><h2><b>How To Prevent a Fluid and Electrolyte Imbalance</b></h2><p><span style="font-weight: 400">The goal of healthy hydration is to maintain proper fluid balance. How should you go about doing that?</span></p><p><span style="font-weight: 400">Medical and pharmacological considerations aside, there are just two principles to follow:</span>&nbsp;</p><ol><li><span style="font-weight: 400">Consume adequate fluids</span></li><li><span style="font-weight: 400">Consume adequate electrolytes</span>&nbsp;</li></ol><p><span style="font-weight: 400">To consume adequate fluids, simply drink to thirst. There are some exceptions (</span><a href="https://drinklmnt.com/blogs/health/why-winter-hydration-is-important" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">cold weather</span></a><span style="font-weight: 400">, altitude, age-related thirst impairment), but drinking to thirst is generally sufficient.</span>&nbsp;</p><p><span style="font-weight: 400">Consuming adequate electrolytes requires more strategy. Start by eating </span><a href="http://rich-foods-and-when-to-supplement" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">electrolyte-rich foods</span></a><span style="font-weight: 400"> for potassium, magnesium, and calcium—then salt those foods liberally for sodium and chloride.</span></p><p><span style="font-weight: 400">My favorite electrolyte sources are green leafy vegetables like spinach, chard, and kale. You can’t go wrong eating tons of greens.</span></p><p><span style="font-weight: 400">Yet diet and salt alone may not cut it. If you eat a whole foods diet, low-carb diet, exercise consistently, enjoy the sauna, or all of the above—you’re going to need more sodium.</span>&nbsp;</p><p><span style="font-weight: 400">Five grams of daily sodium is a good baseline. Go up from there, however, if you’re still having </span><a href="https://drinklmnt.com/blogs/health/symptoms-of-low-sodium-and-how-to-treat-hyponatremia" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">low sodium symptoms</span></a><span style="font-weight: 400"> like fatigue, headache, or cramps. One to two extra grams can make a huge difference in how you feel and perform—and the cool part is that you can feel the difference almost immediately.</span></p><p><span style="font-weight: 400">To bump up your sodium, just add salt to your water. If you want a tastier option, add </span><a href="https://drinklmnt.com/products/lmnt-recharge-electrolyte-drink" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">LMNT</span></a><span style="font-weight: 400">. It contains 1000 mg sodium, 200 mg potassium, 60 mg magnesium, and zero sugar per stick.</span></p><p><span style="font-weight: 400">And so if you want to optimize fluid balance, drink </span><a href="https://drinklmnt.com/blogs/health/electrolyte-water-benefits-and-best-sources" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">electrolyte water</span></a><span style="font-weight: 400"> to thirst in the context of an electrolyte-rich diet. Your body will appreciate it.</span></p>