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Men should drink 13 cups of water each day and women should drink nine cups, according to the National Academy of Medicine.

Your body’s relationship with water is a microcosm of the Earth — just as it’s covered by almost three-fourths water, our body’s water percentage is made up of a similar ratio. If a region rains too much, it floods; if a human drinks too much water, their body can reach a state of hyponatremia. Likewise, if an area of land is too dry for too long, plants and animals will eventually die, just as the human body can shut down in a matter of days from a lack of water. The Earth is also bound by a water cycle that keeps the planet and its organisms hydrated and growing.

On the same token, our bodies need to be refueled with proper fluids on a consistent basis to keep our metabolism and metabolic processes in homeostasis and functioning as they should. 

“Everything that our body does has to have water,” JMU dietetics professor Jeremy Akers said, “from our saliva, down to our feces.” 

The detrimental defects of dehydration 

Among other noticeable changes, Akers said dehydration can affect mental capacity and how joints and muscles feel and perform. Hydration, exercise science professor and director of JMU’s human performance laboratories Michael Saunders said, plays a crucial role in the thermoregulation of our bodies. When we’re dehydrated, Saunders said it becomes challenging for the body to get rid of excess heat. 

As our normal core body temperature hovers around 98.6 degrees Fahrenheit, just a six- to seven-degree increase in temperature will cause our bodies to shut down, Saunders said. This is done to prevent permanent damage to vital organs — like the brain — which begins to rapidly occur when body temperature reaches north of 106 degrees

In this way, our bodies act like a “thermostat,” Saunders said, and hydration plays a crucial role in keeping our metabolic actions functioning so that overheating doesn’t occur.

“All of our body’s cells need water, so we need to keep it within a reasonable [temperature],” Saunders said.

While overheating in the body can harm the brain, hydration is also vital to cool the organ itself, JMU neuroscience professor Melanie Shoup-Knox said. This is in part because the brain is made up of half water and half fat tissue. 

“If you have a dehydrated brain, you’re going to be dealing with headaches and lack of blood flow,” Shoup-Knox said. “It’s going to be hard for that blood to effectively cool the tissue if that tissue is dehydrated.” 

Connie Peterson, JMU associate professor in health professions and athletic training teacher, said athletic performance can also decline when you enter a dehydrated state. Sweat loss equal to just 2% of your body weight can indicate such a performance drop in both physical and mental performance. Moreover, going into physical exercise in a dehydrated state, Peterson said, can put you at greater risk for heat illnesses like heat stroke, heat cramps or heat exhaustion — especially when in a hot and humid environment. 

How to measure hydration status 

To reduce the risk of heat illness, our bodies shutting down or any other dehydration consequences from occurring, it’s important to know how to monitor hydration — and there are multiple ways to do it. 

One way is to gauge the color of your urine. Peterson said that a pale yellow to clear color — or the shade of a “light beer” — indicates adequate hydration. On the flip side, she said you can tell if you’re dehydrated if your urine is amber, or the color of a “stout” or “darker beer.” 

You can also test hydration by measuring your body weight before and after a workout. To see if you’re dehydrated following the physical activity, Peterson said that losing 1-2% of your body weight likely equates to dehydration. Regardless, before your next training session, she said that the weight should be brought back to the pre-workout baseline. 

Peterson said people who are trying to lose weight can still test hydration status by weighing themselves before and after workout sessions, but that they should go for a 1-2% drop in weight per week. Weight loss shouldn’t come at the expense of losing water weight, she said. In fact, drinking water can actually curb your hunger and prevent other food cravings from coming on. 

“You’re trying to lose the fat weight,” Peterson said. “In order to do that, in order for your metabolism and all those things to be at their optimal functioning level, you need to be hydrated.”

Peterson said that especially when immersed in physical activity, you shouldn’t use thirst as a gauge for when to drink water. This is because our thirst mechanism lags behind our hydration state since the fluid has to go through our stomach, into our intestines and then be distributed into the blood to be circulated through the body. This means you don’t get thirsty until you’re dehydrated — which can be “too late,” Peterson said, on a hot and humid day. For those going about regular daily living, she said you’re “probably going to be fine” using thirst as an indicator for when to rehydrate.

The amount of water we should be drinking per day depends on your sex, age and body size. The National Academy of Medicine — formerly known as the Institute of Medicine — recommends grown men should drink about three liters — or 13 cups — of water per day, while women should drink a little over two liters — or nine cups — per day. Children and teens should be drinking six to eight cups of water per day, according to the same article. 

Weight also plays a factor in adequately hydrating. Orthopedic clinical specialist Jennifer Stone said we should take half our body weight and drink that amount in ounces of water. For example, a 160-pound man should drink around 80 ounces of water per day before physical activity and other hydration-consumption variables are taken into account. For reference, one liter equates to roughly 33 fluid ounces. 

However, the ratio only serves as a baseline. Peterson said hydration status also greatly depends on two more variables: intensity of physical activity and outside temperature — the hotter and more intense you’re working out, the more you’ll likely sweat, and therefore hydration becomes increasingly important. 

The National Academy of Medicine recommends adding 12 ounces of water for every 30 minutes that you plan to work out. Even if you’re not doing strenuous physical activity, 90-degree weather can “more than double” requisite fluid replenishing, healthcare journalist Shereen Lehman said. Fresh fruits that are rich in water — like grapes, peaches and watermelon — can also aid hydration during a hot day. 

Moreover, people have unique outputs of sweat that include differing amounts of sodium and water, Peterson said, which needs to be accounted for when replenishing fluids and recovering to a hydrated state. 

The Gatorade Sports Science Institute (GSSI) helped develop sweat patches that determine the concentration of your sweat and what method of rehydrating will adequately bring you back from a dehydrated state. The packets stick on your forearm during workouts and present a reading in an orange dye that helps you decide whether you need a replenishing drink with a large amount or small amount of sodium. 

Sports drinks as hydrators — necessary?

Because we lose more than just water when we sweat, sports drinks — like Gatorade and Powerade — come into play. Much of the research on sports drinks’ hydration benefits is biased because it’s largely conducted by the GSSI, who gains financially from studies that put their Gatorade products in a positive light. Peterson said that despite the studies, there are sweat-replenishing products that are “equally as good or even better” than some of Gatorade’s when looking between the lines. 

JMU graduate Andy Allen (’20), Masters of Science in kinesiology and personal trainer at Future, said sports drinks like Gatorade are beneficial when you’re training “intensely” or going “heavy” because the drink’s electrolytes, potassium and carbohydrates all help replenish your sweat. However, he said it’s best to pair sports drinks with water to prevent having “all sugar all the time.” 

In order to limit his sugar intake, Allen said he drinks Gatorade Zeros instead, and it helps keep his taste buds “happy” because he’s not a soda drinker. On the contrary, Shoup-Knox said that drinks with artificial sweeteners can trick our brains into releasing glucose from our brain in anticipation of sugar, which can decrease optimal brain performance. 

Gatorade and other sports drinks contain food that our brain and central nervous system want to feed off in the form of carbohydrates, Allen said. These carbohydrates provide the body with a little “fast fuel energy” for muscles when workouts extend past 90 minutes, Peterson said — but in workouts under that time, she said water will suffice. Peterson said you can end up with a “sloshy gut” if you consume too much of a sports drink during a workout because it eventually stops being absorbed by our intestines. Sports drinks can also be consumed after a workout to continue replacing lost electrolytes, but shouldn’t be consumed throughout the day in place of water. 

Other than providing an energy boost in longer workouts, Peterson said the appeal of Gatorade and other sports drinks relies on their ability to transfer the sodium and electrolytes across the cell membrane and into the cells. The carbohydrates are the culprit of this, she said, and doing so helps rehydrate cells faster than water, which doesn’t contain carbohydrates. 

There are other unconventional hydrating fluids that help treat a very conventional inhibition when working out in hot environments: cramping. Pickle juice and mustard packets can help combat cramping because of the acidity that’s in both, Peterson said. She said cramping is somewhat due to electrolyte imbalance, but more so due to muscle fatigue or asking your muscles to do something they’re not used to doing. Peterson said that a friend of hers began to drink mineral water and saw a dramatic reduction in her frequency of cramping, but she said she isn’t keen on the research or validity of mineral water being a solution to cramps. 

Whether we’re trying to reduce cramping, or just have our bodily functions operating efficiently, adequate hydration is what will get the job done. 

“If we’re depriving the body of water, [then] we’re not going to be able to optimally perform in anything we’re trying to do,” Allen said.” 

Contact Grant Johnson at breezecopy@gmail.com. For more health & wellness content, stay tuned for the “A Wealth of Health'' column every Monday and follow the culture desk on Twitter and Instagram @Breeze_Culture.