Nothing beats a big glass of water when you’re thirsty. In fact, the CDC’s daily recommendations for water is 91 ounces of total water for women and 125 ounces for men (1). The importance of water for overall health goes far beyond just quenching thirst. Water is found in more places in the human body than you may realize. Our blood and our muscles are primarily made of water. Our body fat, and every other part and organ in our body has a water component as well. Water is the fuel our bodies need for biochemical reactions, thermoregulation, detoxification, and moisturization. And this water doesn’t just come from what we consume; in fact, our bodies can produce 8-16 ounces of water a day during cellular respiration, the process by which we create cellular energy in the mitochondria. But just as we create and intake water, we excrete it. Excess nutrients, metabolic products, electrolytes, toxins, and drugs are expelled through our urine, and water is the main component in our urine, which flushes out that waste (2). We expel water through our saliva, through sweating, which balances inner temperature, through our lungs to keep our respiratory system moist, and tears to keep our eyes moist, so maintaining fluid balance is paramount for health (3).
Dehydration develops from inadequate fluid intake or excessive fluid losses. Diagnosis of dehydration as a comorbidity at admission to hospital is estimated at more than 500,000 older adults annually in the US (4). Besides the dryness we can feel in our mouth when we are thirsty, dehydration can lead to less visible side effects such as constipation, headaches, renal dysfunction, and impaired cognitive performance at or above 2% water loss (5). The degree of reduction in cognitive performance depends on environmental and individual factors like the level of fitness and dehydration tolerance (6). In women, aspects of mood like alertness, energy, calmness, concentration, and happiness are all negatively affected during fluid deprivation (7). Chronic dehydration can cause altered absorption of medications and nutrients, as well as delirium (8). Dehydration can also cause electrolyte imbalance and low blood pressure (3).
As we age, our kidneys lose some of their ability to concentrate urine. Rennin, which helps maintain blood pressure, becomes less active in the body as we age. Older adults secrete less aldosterone, the hormone that regulates water and salt balance, as well as less vasopressin, which acts as an antidiuretic (9). Unfortunately, loss of muscle mass will lead to loss of total water concentration in the body (another reminder to continue with your resistance training) (9). Because of this, older adults needs to pay even closer attention to hydration status.
Listening to thirst is a great indicator of dehydration, but we may not always be in tune with those cues. Cognitive loss may inhibit or impair thirst cues (8). Looking at urine can be a natural guide. A common sign of dehydration is urine that has a strong smell and is clear, dark yellow. If you have been properly hydrating, your urine should have a faint smell and appear pale yellow or clear.
If finding time to fit in water consumption outside of meals is difficult, try keeping spare bottles of water in the car or in the house so they are convenient to grab. If you have a hard time getting adequate water intake, try to enhance your water to make it more appetizing. Fresh fruit and veggies are great for infusing water to provide flavor. Citrus slices add a bit of sweetness to water, and cucumber + mint is a refreshing and cooling combination. Try out sparkling water without artificial sweeteners or added sugars if you find that to be more appealing than still water. Additionally, focus on foods that provide free water. Watermelon is an obvious source (ahem, the name), but other fruits and vegetables have a high-water content, too. Besides other health benefits, cucumbers, citrus, berries, and lettuce will help with hydration. Herbal teas such as rooibos and chamomile can be a flavorful alternative to water, and they can be consumed iced or hot.
Make sure you are adequately hydrating on a daily basis and more importantly, on hot days or during physical activity. Surprisingly, even long telephone chats can cause dehydration through the loss of saliva! The main point here is to hydrate and make water consumption a routine in your life. We depend on adequate water intake because of the huge impact water has in the body, whether it’s the physical, mental, or biological effect.