Everyone ran track when I was in high school. Ok, maybe not everyone, but at least two hundred awkward teenagers showed up on the first day of practice, eager to either get ready for bathing suit season or to appear sporty on their college admissions application.
The first day of practice was not pretty: 20+ kids were lined up at the fence line, vomiting; another sizable group was hiding behind the weight room, avoiding the shouting coaches; then there was the group of criers; at least one kid blacked out. You get the picture.
The number of participants dropped by half within the first week, stabilizing at about a quarter of the initial participants a few weeks in.
Do you know what was missing from this grim picture? Water! Sure, there were large orange Igloo containers that had been borrowed from our epicly bad football team, but water breaks were infrequent and no one really knew (coaches included) how to properly hydrate their bodies.
The coaches brushed the vomiting off as a natural weeding out process, or part of the initial hazing. Now that I know so much about the performance benefits of hydration, though, I wonder how many kids would have continued on the team if they had taken more frequent water breaks?
Research in athletes shows the greatest risk of dehydration occurs at the beginning of the season (hello day #1 of track practice), when athlete’s bodies have not adequately acclimated to the current weather conditions. In general, it’s not uncommon for athletes to lose 6-10% of their body weight in sweat (human performance is affected at even a 2% loss of fluids).
The performance hit from dehydration isn’t just physical. Mild to moderate dehydration can also have dramatic effects on cognitive performance as well - short-term memory, perceptual discrimination, arithmetic ability, visuomotor tracking, and psychomotor skills . In high-stakes military situations, where physical and mental acuity are imperative to survival, preventing dehydration becomes essential.
In this article we will delve into the science of dehydration and attempt to answer the following questions:
- What important roles does water play in the functioning of the human body?
- What are the common signs and symptoms of dehydration?
- What’s happening inside my body when I don’t get enough water?
Let’s dive in!
You are (mostly) water.
The human body is up to 60% water. To break it up even further, our brains are composed of roughly 73% water and even our bones contain water - around 31% in fact. Kid's bodies are composed of more water than adults. Babies, not surprisingly, have the highest percentage - with their bodies being roughly 78% water at birth  (Bananas are 75% water as a comparison point!).
Our body also uses water for a number of essential functions: regulating body temperature, dissolving essential nutrients so our body can absorb them, and as a conduit for carrying nutrients and oxygen to our cells . Humans can survive for up to three weeks without food. Water though is a totally different story. Survival drops to 3-4 days without a water supply .
Some of the basic symptoms of mild dehydration are obvious - basic thirst, dry and sticky mouth, dark yellow pee, headaches, and muscle cramps to name a few. Severe dehydration, a true emergency requiring medical intervention, looks more extreme: dizziness, dry skin, rapid heartbeat and breathing, sunken eyes, and fainting. A good rule of thumb is to look at your urine. Dr. Lawrence Armstrong invented something called the Armstrong Chart.
Imagine a series of paint swatches linked together - the lightest one has a faint yellow hue and the darkest one looks like dark mustard. The goal is to keep the color of your urine in the lightest three hues to keep your body functioning at its best . Armstrong Charts can be frequently found in elite athletic environments where “clear and copious” is the rule of thumb.
Bad breath is one of the more unusual signs of dehydration. Saliva contains antibacterial properties. When your body is dehydrated, it produces less saliva, resulting in built up bacteria in your mouth (and an unpleasant stink!). Sugar cravings are another sign of dehydration.
Without adequate water, your liver can’t break down its energy stores. To compensate, our bodies start craving sugar to replace the missing energy . Thirst and hunger can actually get jumbled in this scenario. Drinking a glass of water before snacking is a great way to ensure you are reading your body’s signals correctly.
Blood tests, although not easily accessible, can also reveal information on dehydration levels. According to the Mayo Clinic: “Blood samples may be used to check for a number of factors, such as the levels of your electrolytes — especially sodium and potassium — and how well your kidneys are working.” This one is obviously not easy to gauge on your own, but can be used by medical professionals to monitor patients.
Why and how our bodies have such innate intelligence is a discussion for another time. All I know, is that the ability of the human body to maintain homeostatis is pretty frickin’ amazing. The inner workings of your body in the face of dehydration is no exception. Let’s take a quick look at two of the processes going on within your body when you aren’t getting enough water:
Your blood actually becomes more concentrated as you sweat off water without replacing it. This thickening of sorts, signals your kidneys to retain water (thus decreasing urine output). Thicker blood also means your heart has to work harder to pump the blood throughout your body. Your heart rate goes up when your heart is working harder. In high performance scenarios, where you are pushing your body past its normal limits, collapse and heat exhaustion become higher risks as a result .
As you dehydrate, your body’s ability to stay cool also reduces. Hyperthermia, or an elevated internal body temperature, results. All the little enzymes in your body, responsible for normal metabolic function, don’t work well at elevated temperatures. Prolonged hyperthermia can affect organs that have higher metabolic demands, such as the heart and brain .
So, in the end - how much water do you need? Check out this article about the health benefits of water to learn more.
About Qore Performance
Last summer Qore Performance customers worked 200,000+ man hours without a single heat incident. From industries as varied as fast food, airlines, HAZMAT, and military - our products cool bodies conductively and keep hydration close at hand. Learn more about IcePlate and our HiVis StayFrosty Vest to keep your employees safe and to increase your performance in the field.