Considering that the human body is upwards of 60% water, maintaining adequate hydration is fundamental to good health. With so many enticing energy drinks, fruit juices, bottled tea and coffee on the market, humble, life-sustaining, plain ol’ water sometimes gets forgotten. Dehydration obviously has disastrous effects. Water is so critical to processes throughout the body that when there isn’t enough to go around, the body may perform a kind of triage, prioritizing the use of water in some systems, while causing shortages or imbalances elsewhere. Due to water’s role as a constituent of blood, digestive secretions, synovial fluid, cerebrospinal fluid, and more, insufficient hydration can lead to acute as well as chronic health problems, including some that may be life-threatening.
Patients have long been counseled to consume approximately eight-8oz glasses of water daily just to maintain a baseline of hydration, and then consume additional amounts if they are physically active, and if the weather is hot and dry. People seeking to lose weight often receive advice to “fill up” on water, in an effort to consume fewer calories from food. Unfortunately, overhydration from excess water consumption can result in complications just as dangerous and deadly as those of dehydration. And overhydration is no longer a very rare occurrence limited to marathon runners. It’s happening in other sports, too, even among high school athletes, and there have also been incidents of dangerous overhydration resulting from university fraternity hazing rituals.
Hyponatremia may result from specific medical conditions (such as syndrome of inappropriate antidiuretic hormone secretion [SIADH]), but when it is the consequence of deliberate or inadvertent consumption of excessive amounts of water, the other name for hyponatremia—water intoxication—emphasizes just how dangerous a situation it can be. Some of the symptoms of hyponatremia are attributable to swelling in the brain, which is why this condition must be taken seriously and may require immediate medical attention. Pulmonary edema is another dangerous potential effect of hyponatremia.
Regarding adequate hydration, individuals should let thirst be their guide. The oft-repeated saying that when you’re thirsty, it’s already too late, is incorrect. Common sense should be a guide, too. If someone has been sweating a lot, they should replace water and electrolytes, either with a beverage or supplement specifically formulated for that purpose, or even by adding a pinch of unrefined salt to their water.
According to the 2015 consensus statement regarding exercise-associated hyponatremia (EAH) published in the Clinical Journal of Sport Medicine, “The safest individualized hydration strategy before, during and immediately following exercise is to drink palatable fluids when thirsty. Studies verify that participants allowed free access to fluids during treadmill walking in the heat or running 30 km under different ambient conditions maintain plasma osmolality by drinking to thirst. Thus, drinking to thirst will, in most cases, prevent both dilutional EAH and performance decrements due to excessive dehydration.”
The experts agree: there is no need to engage in “prophylactic hydration” above and beyond normal water consumption. Patients should let thirst and common sense be their guide, paying attention to how much they’re sweating, whether they’re replacing electrolytes, and, above all, how they feel. As with all vital nutrients, people can get too much of a good thing. Just because some water is essential, it doesn’t mean more is always better.
Note: I ask with every one of my patients how much water they should be drinking and across the board it is somewhere between 64-96 ounces
Note: The brain signal for hunger and thirst are similar. Sometimes when one is hungry, they really are thirsty.
Note: Animal Protein requires more water to digest while foods cooked in water such as brown rice require less. Sugar also requires more water.