Hydration as Medicine

8-29-2025

By Dr. Howard Friedman MD | Veteran | U.S. Army Medical Corps | Internal Medicine | HHOM LLC

A glass of water on a physician’s desk—reminder that the simplest medicine is often the most vital. Hydration sustains clarity, protects the kidneys, and keeps the body in balance

A stream runs quiet, yet keeps us alive,

It carries the breath, helps cells to thrive.

A soldier’s canteen, a mother’s well,

Stories of water our bodies still tell.

We forget its voice, but it whispers clear:

“Without me, healing will not appear.”

—Dr. Howard Friedman, MD

Thesis- hydration as medicine

We speak often of medicines, supplements, and diets, yet the simplest prescription is the one we forget: water. Hydration is not a lifestyle choice, but the foundation of survival, performance, and healing. Hydration as medicine.

Hydration as Medicine- The Forgotten Prescription

Water is not just a drink; it is the body’s oldest medicine. Each swallow is a quiet prescription—cooling heat, carrying oxygen, washing away waste, loosening joints that would otherwise grind in protest. It cushions the brain, cradles the spinal cord, and even begins the simple miracle of digestion in a drop of saliva.

Soldiers have always known this. In the military, water is survival—canteens strapped to belts, strict MOPP breaks in suffocating heat and humidity. The lesson was clear: without water, the mission fails, the body collapses.

And what about us? We still remain fifty, sixty percent water, depending on age, sex, season of life. Some say we rose from the oceans themselves, and perhaps that is why water feels less like a choice and more like a homecoming.

This blog is about remembering what the body never forgot: hydration as medicine, water as life.

The Physiology of Thirst and hydration as medicine-

Water is two atoms of hydrogen bonded to one atom of oxygen. Simple on the surface, yet essential for every form of life we know. This compound shifts between liquid, gas, and solid—an adaptability mirrored in the body’s own systems built to guard its balance.

At the core of this regulation is the hypothalamus. This small but powerful structure constantly monitors blood osmolality—the concentration of water relative to solutes. When water runs low, the hypothalamus triggers the release of antidiuretic hormone (ADH), also known as vasopressin, stored in the pituitary gland. ADH travels to the kidneys, signaling them to conserve water. Capillaries reclaim it, urine becomes concentrated, and blood volume and pressure rise back toward normal. In parallel, the hypothalamus sparks the drive we call thirst, pushing us to replenish what has been lost.

It is not the volume of water alone that matters, but its concentration—osmolarity—that is tightly controlled. Yet, like any fine-tuned system, this regulation is vulnerable. Aging, chronic inflammation, and certain medications can dull the hypothalamus’ sensitivity or block thirst signals altogether. Some drugs act as diuretics, pushing water out; others blunt awareness of thirst, leaving the body quietly dehydrated.

Disruption of this circuit carries consequences: weakened signaling means hydration falters, organs strain, and inflammation finds yet another foothold. In health, thirst is a signal. In disease, it can become a whisper too faint to hear.

Aging and the Lost Thirst Signal: Why Hydration as Medicine Matters

Thirst is supposed to be a reliable guide. The hypothalamus senses rising concentration in the blood and sends the urge to drink. But as the years pass, this signal weakens. Older adults can slip into dehydration without even realizing it. The body needs water, yet the mind never feels the cue.

This blunted thirst response is one reason dehydration is so common in the elderly. Add in medications—diuretics, antihypertensives, antidepressants—that either pull water out or dull awareness, and the risk rises even higher. A person can be clinically dehydrated without ever feeling truly thirsty.

The consequences are not minor. Dehydration in aging bodies can trigger confusion, dizziness, kidney strain, and spikes in inflammation that accelerate chronic disease. Falls, hospitalizations, even cognitive decline often trace back to what seems simple: not enough water.

Prevention here means habit over instinct. Drinking on schedule, not just when thirsty, becomes the safeguard. It is a quiet discipline, but one that preserves clarity, balance, and health.

 Military Lessons: Hydration as Medicine in the Field

In the Army, water was never an afterthought—it was protocol. Canteens strapped to our sides, hydration breaks were ordered, not requested. Under Mission-Oriented Protective Posture (MOPP) gear, with heat and humidity closing in, you didn’t wait for thirst. You drank because survival demanded it. Command understood what science confirmed: by the time thirst arrives, performance is already compromised.

These lessons are written in sweat and discipline. Dehydration dulls reflexes, clouds judgment, and slows reaction time—the very things soldiers cannot afford in the field. A lapse in water intake could mean confusion on patrol, delayed response in combat, or collapse in training. Hydration wasn’t about comfort; it was strategy, protection, and readiness.

Civilian life rarely carries the same urgency. Yet the physiology has not changed. Outdoor workers laboring in the heat, athletes pushing endurance, or even office staff in air-conditioned buildings share the same biology. When water is neglected, fatigue deepens, inflammation smolders, and the body slips out of balance. The soldier’s lesson applies that hydration must be intentional, not optional.

Nowhere is this more evident than in the kidneys. These organs depend on a constant flow of water to filter waste and maintain electrolyte balance. When intake falls short, urine concentrates, crystals form, and kidney stones can develop—a painful reminder that prevention is easier than repair. Chronic dehydration also strains the kidneys’ filtering capacity, raising long-term risks of kidney disease.

What the military enforced out of necessity is wisdom for everyday life—drink before thirst, replenish steadily, and protect the organs that guard your internal balance. In combat, water preserved life. In daily living, it preserves health.

The Kidneys ------ Silent Guardians of Hydration as Medicine

The kidneys are the body’s great filters, working every minute to clear toxins, balance electrolytes, and keep blood volume steady. They depend on water to flush waste smoothly. When hydration falters, urine concentrates, minerals crystallize, and kidney stones can form—one of the clearest signals that prevention has been ignored. Over time, repeated dehydration can scar these filters, leading to chronic kidney disease.

Kidneys don’t complain until the damage is advanced. By then, fatigue, swelling, and high blood pressure may already be present. Staying hydrated is one of the simplest ways to protect them. Water keeps their microscopic vessels flowing and spares them the burden of overwork.

For me, these subject carries weight. I lost my best friend in 2008 to kidney cancer. Not a day passes without the reminder: the kidneys matter. They are silent guardians—easily overlooked, but irreplaceable. Protecting them begins with something as simple as a glass of water.

Overhydration and Myths

If dehydration is a danger, so is its opposite. In recent years, a wave of health advice has urged people to carry water bottles everywhere, sipping constantly as if more is always better. But the truth is more complicated.

Overhydration, or water intoxication, dilutes the body’s sodium levels. When sodium falls too low—hyponatremia—the balance of fluid shifts into cells, including those of the brain. The result can be confusion, nausea, seizures, even death. While rare, it most often appears in endurance athletes who drink excessively without replacing electrolytes, or in individuals convinced that gallons a day must be healthy.

There are also medical conditions where water balance is severely disrupted. Diabetes insipidus, for example, is caused by a lack of antidiuretic hormone (ADH) or the kidneys’ failure to respond to it. The result is relentless thirst and the production of enormous volumes of dilute urine. Unlike diabetes mellitus, it is not about sugar, but about water itself—and it can be life-threatening if not recognized and treated. In this disorder, the body cannot hold water no matter how much is consumed, leading to dangerous dehydration and electrolyte imbalance.

The common myth that “eight glasses of water a day” applies to everyone is just that—a myth. Hydration needs vary by body size, activity level, diet, and climate. Fruits, vegetables, soups, even coffee and tea all contribute to water intake. The body is not rigid, but flexible. The goal is balance: enough water to keep urine pale, joints lubricated, and energy steady—not so much that electrolytes are drowned.

The military never taught us to drink endlessly. We were taught to drink wisely, in rhythm with exertion, temperature, and sweat loss. The same wisdom applies to daily life. Hydration is medicine, but like any medicine, dose matters.

 

Diabetes Insipidus Overhydration and Myths

Not all thirst is ordinary. In diabetes insipidus, the brain does not release enough antidiuretic hormone (ADH), or the kidneys fail to respond to it. The result is relentless thirst and the production of enormous volumes of dilute urine. Unlike diabetes mellitus, it has nothing to do with sugar—this is a disease of water itself.

Left untreated, it can lead to dangerous dehydration, electrolyte imbalance, and even death. Recognition and medical care are essential. Diabetes insipidus reminds us that hydration is not just wellness advice; it is a matter of survival.

The 8 - Glasses Rule and the Truth About Hydration as Medicine

Many people still believe in the “eight glasses of water a day” rule. The truth is this number traces back to a 1945 U.S. Food and Nutrition Board recommendation that adults consume about 2.5 liters of water daily. But what’s often forgotten is the second half of the sentence: “Most of this quantity is contained in prepared foods.”

Somewhere along the way, the context was lost. What began as a general nutrition statement became a rigid commandment. In reality, hydration needs shift with climate, exertion, health conditions, and even what you eat. A summer construction worker in Texas does not have the same needs as an office worker in Ohio.

The lesson: let physiology, not slogans, be your guide. Pale urine, steady energy, and clear thinking are better markers than counting glasses.

Lessons from the Field

The field teaches what textbooks often forget: water is not optional, it is survival. Soldiers learned quickly that hydration determined not just endurance, but judgment, strength, and even life itself. A soldier falling out of formation from heat injury was not weak; he was dry. Water became discipline, carried in canteens, measured in sips, and enforced by command.

Those lessons hold beyond the uniform. In civilian life, the battlefield may be a construction site, a factory floor, a summer marathon, or even the quiet strain of long hours under fluorescent lights. The need is the same: hydration keeps the body sharp, the mind clear, and the immune system ready. When ignored, performance drops, accidents rise, and chronic illness finds its foothold.

The field also teaches humility. No one is tougher than physiology. The strongest soldier collapses if he ignores water. The fittest worker falters if thirst is silenced. Hydration is not weakness; it is readiness. Water is medicine, but unlike pills, it comes without a prescription. The lesson is simple, but not easy: drink with discipline, not just desire. In the field, it preserved the mission. In life, it preserves health.

 

Conclusion --- The Forgotten Prescription

Water is more than a drink—it is a prescription written into our biology. From the hypothalamus that governs thirst, to the kidneys that filter waste, to the soldier in the field whose endurance depends on his canteen, hydration has always been the quiet foundation of health. Too little and the body falters, too much and body’s  balance unravels. The lesson is balance: water taken steadily, wisely, and with intention.

In daily life, this means drinking before thirst, protecting kidneys, guarding cognition, and preventing inflammation. It means respecting the body’s signals while remembering the wisdom of the field—hydration is readiness.

A final word on bottles. Plastic has made water convenient, but it carries its own risks—to the environment and, at times, to health. Whenever possible, choose reusable containers, filtered tap water, or sustainable sources. Let hydration be healing not just for the body, but for the world around us.

Thank you for reading. At Howard’s House of Medicine, our mission is simple: to bring forward lessons that preserve health, prevent illness, and honor the wisdom of both medicine and lived experience. May your next glass of water be more than refreshment—it is medicine, freely given.

Before the pill, before the blade,

A simpler cure was always made.

A sip, a stream, a flowing art

—The oldest medicine is water’s heart.

—Dr. Howard Friedman MD

Board-Certified | Internal Medicine | Veteran | U.S. Army Medical Corps

Founder of Howard’s House of Medicine (HHOM LLC)

https://www.hhomllc.com

Frequently Asked Questions:

Q: Why is hydration considered a form of medicine?

A: Hydration supports every system in the body. Water cushions the brain and spinal cord, lubricates joints, aids digestion, clears waste through the kidneys, and even regulates temperature. Without it, inflammation increases and healing slows. It is the oldest, simplest prescription the body relies on daily.

Q: How does aging affect the body’s thirst signal?

A: As people age, the hypothalamus becomes less sensitive to changes in hydration. This means older adults often don’t feel thirsty even when they are dehydrated. Combined with medications like diuretics, this can lead to confusion, dizziness, kidney strain, and even hospitalizations. For this reason, scheduled drinking—rather than waiting for thirst—is often necessary.

Q: Do we really need eight glasses of water a day?

A: The “eight glasses a day” rule is a myth. Hydration needs vary with activity level, climate, diet, and health conditions. Water from food, soups, fruits, tea, and coffee all contribute to total intake. The best guide is physiology: pale urine, steady energy, and mental clarity are more reliable than counting glasses.