Many years ago, I worked for six months in an emergency room in Española, north of Santa Fe. While on duty, three young adults came into the ER pushing their grandmother in a wheelchair. The grandmother looked disoriented. One of the grandkids insisted that she get a CT scan of her brain because they were sure she had a stroke. I asked them what made them diagnose her as having a stroke. The oldest grandchild said that when they arrived at her house for a visit, the grandmother didn’t know their names.

“I need to leave you right now and attend to people injured in a motor vehicle accident. I’ll be back in about 45 minutes. In the meantime, the nurse will start an intravenous drip on your grandmother,” I assured them.

I told the nurse to give the grandmother a full liter bag of saline solution and to open the tube all the way.

When I returned to treat the grandmother, she was alert, talkative and lively. She knew all the names and ages of her grandchildren. She did not have a stroke. She suffered from profound dehydration.

More recently, a patient came to see me because she feared that she was getting dementia. After talking with her, I discovered that the cognitive problem occurred intermittently. Usually her mind was sharp, but occasionally she became confused and couldn’t remember people’s names.

If the cognitive decline only occurred intermittently, we needed to determine what caused those transient episodes.

She assured me that her episodes were not from poor sleep which rarely occurred, except for occasional severe leg cramps during the night which kept her awake. We looked at her diet to see if heavily processed food played a role. We ruled that out. She said that she drank coffee in the morning, sometimes up to three cups. And she drank a small glass of wine in the evenings. (Caffeine and alcohol act as diuretics, which means you lose fluid from drinking them.) From there, I asked what she drank from the time she got up in the morning until the time she went to bed. I discovered that she had some days where she didn’t drink any water, but she did get some liquids for her soup and from her orange juice. We discovered that on those days she often had the nocturnal leg cramps.

I asked her to keep track every day of her fluid intake, not including caffeine and alcohol. Based on her height and weight, I asked her to drink at least 3 quarts a day of clear fluids, and to be sure to include some plain water. When she returned two weeks later, she said the episodic cognitive issues had disappeared.

Of course, lack of sufficient fluids is only one of the many factors that influence cognition.

Why does this lack-of-thirst phenomenon occur in older people, you might ask. Young people usually don’t need to worry about their fluid intake because they get a strong thirst signal. That signal comes directly from the hypothalamus in the brain.

The hypothalamus is a small but critical region of the brain that acts as your body’s command center. Its primary job is to maintain homeostasis, which means keeping your body’s internal systems—like temperature, hunger, thirst, and sleep—in a stable balance. It has multiple functions which affect the nervous system and the hormone-producing endocrine system.

 

One of the many functions of the hypothalamus involves detecting changes in both blood sugar and salt levels. If it detects too much salt in your blood, you will get a thirst signal which will make you want to drink more fluids. The increase in fluids will quickly dilute the salt imbalance.

In young people, the hypothalamus is intact. You don’t need to tell young people that they need to drink more water. They get a strong thirst signal.

As we age, we start to lose the strength of the thirst signal due to aging of the hypothalamus. Therefore, we need to work around that problem. In my case, I have a glass pitcher on my counter that holds 2.5 quarts of water, based on my height and weight. The formula is a quart of water for every 50 pounds. If you’re severely overweight, you would count your lean weight, like what you weighed in high school. And if you’ve been out hiking in the hot sun, then you would drink an extra quart.

Every morning I put filtered water into the glass pitcher which gives me a visual reminder on how I’m doing with fluid intake. The pitcher needs to be empty by the end of the day. Approximately half of what I drink is plain water. The rest of the water is used for broth, herbal tea, a freshly squeezed lemon or lime drink, or I add a splash of Kombucha fermented tea into my glass of water.

When severe dehydration hits older people, the brain and the kidneys are impacted the most. The brain cells begin to shrink, causing confusion and extreme lethargy. The drop in blood volume causes a drop in blood pressure, which in turn causes decreased blood flow to the kidneys, resulting in kidney failure.

Before wrapping up, I want to make sure that you don’t go overboard in your attempt to stay hydrated. I had a patient who had a history of being sent to a psychiatric hospital when she was a teenager due to over hydration, known as water intoxication.

Consistently drinking too much water leads to dangerously low blood sodium levels, known as hyponatremia. This state causes cells, including brain cells, to swell. Symptoms progress from vague discomforts to severe neurological emergencies and can escalate quickly.

I hope you found this information useful.

Here’s to your good health!

Dr. Erica

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On a different note, I wanted to let you know that I’m working on my 4th book which will not be a memoir. The title of the book is “The Medical Detective: Simple Solutions for Solving Medical Mysteries.” There will be 30 case histories with in depth discussions of each case. I’m guessing it will take me a year before it will be ready for publication.

At the risk of sounding like a broken record, I would be so grateful if you would be willing to write a review on Amazon about any or all of my books in the trilogy: “Medicine and Miracles in the High Desert: My Life Among the Navajo People,” From Mountains to Medicine: Scaling the Heights in Search of My Calling,” and “From Doctor to Healer.” Amazon has an algorithm that makes it impossible for a book to be visible to someone scrolling in search of a book of my genre to appear–unless one has well over 100 written reviews. Your review could be as short as one sentence. My brother wrote “Great Book.” He’s a man of few words.