It’s simple to avoid but can sneak up on you, even if you think you are drinking enough to replenish the water you are losing through perspiration. The human body is made up of mostly water, with up to 75% of the body’s weight due to H2O (the average is 60% with a range of 45 to 75 %). Most of the water is found within the cells of the body (intracellular space). The rest is found in the extracellular space, which consists of the blood vessels (intravascular space) and the spaces between cells (interstitial space).
Dehydration, as you can imagine, occurs when the amount of water leaving the body is greater than the amount being taken in. The human body is very dynamic and always changing, this is especially true with water levels in the body. We lose water routinely when we:
- breathe and humidified air leaves the body
- sweat to cool the body
- urinate or have a bowel movement to rid the body of waste products
Mild Dehydration is present when a loss of 1-2% of the total body water volume exists. Mild Dehydration can lead to moodiness and poor concentration. In a normal day, a person needs to drink a significant amount of water to replace this routine loss. Each person’s requirements vary but the suggested average is eight 8oz glasses of water.
For this article we will focus on sweating as the main cause of dehydration. However, mild to severe Dehydration can be a symptom of many other causes including but not limited to Diarrhea.
When we exercise, the body will lose significant amounts of water when it tries to cool itself by sweating. Whether the body is hot because of intense exercising, the environment (for example, working in a warm environment), it uses a significant amount of water in the form of sweat to cool itself. The body keeps cool by circulating blood to the skin, where water is lost from the blood in the form of sweat. When sweat evaporates, it cools the skin. This in turn cools the blood that is carried to the body core. Depending upon weather conditions, a brisk walk can generate up to 16 ounces of sweat (one pound of water!).
The body’s initial responses to dehydration are thirst to increase water intake along with decreased urine output to try to conserve water. The urine will become concentrated and more yellow in color – a good sign it’s time to drink more water. As the level of water loss increases, more symptoms can become apparent, such as increased thirst, dry mouth, cessation of tear production by the eyes, cessation of sweating , muscle cramps, nausea and vomiting, heart palpitations, and lightheadedness (especially when standing).
In cases of severe dehydration, confusion and weakness will occur as the brain and other body organs receive less blood. Finally, coma and organ failure will occur if the dehydration remains untreated.
Dehydration symptoms generally become more noticeable after 2% of one’s normal water volume has been lost. Initially, one experiences thirst and discomfort, possibly along with loss of appetite and dry skin. This can be followed by constipation. Athletes may suffer a loss of performance of up to 30% and experience flushing, low endurance, rapid heart rates, elevated body temperatures, and rapid onset of fatigue.
Symptoms of mild dehydration include thirst, decreased urine volume, abnormally dark urine, unexplained tiredness, irritability, lack of tears when crying, headache, dry mouth, dizziness when standing due to orthostatic hypotension, and in some cases can cause insomnia. As mentioned, mild dehydration also has been shown to negatively impact people’s moods. Symptoms become increasingly severe with greater water loss. One’s heart and respiration rates begin to increase to compensate for decreased plasma volume and blood pressure, while body temperature may rise because of decreased sweating.
At around 5% to 6% water loss, one may become groggy or sleepy, experience nausea, and may feel tingling in one’s limbs, headaches similar to what is experienced during a hangover, muscle cramps -especially leg cramps, a sudden episode of visual snow, decreased blood pressure. When untreated, dehydration generally results in delirium, unconsciousness, swelling of the tongue and, in extreme cases, death.
With 10% to 15% fluid loss, muscles may become spastic, skin may shrivel and wrinkle, vision may dim, urination will be greatly reduced and may become painful, and delirium may begin. Losses greater than 15% are usually fatal.
What Can You Do To Avoid Dehydration?
- Replace fluids at a rate that equals the loss.
- Plan ahead and take extra water when temperatures are higher than normal, heat stress will increase fluid loss.
- Avoid alcohol consumption, especially when it is very hot, because alcohol increases water loss and impairs your ability to recognize early signs associated with dehydration.
- Take more breaks to reduce your exposure to hot temperatures. Find air-conditioned or shady areas and allow yourself to cool between motos.
- Know the signs and symptoms of heat cramps, heat rash, heat exhaustion, and heat stroke. Preventing dehydration is one step to avoid these conditions.
During the Chicago heat wave of 1995, more than 600 people died in their homes from heat exposure. And they were most likely not riding dirt bikes!
How is Dehydration Treated?
Fluid replacement is the treatment for dehydration. This may be attempted by replacing fluid by mouth, but if this fails, intravenous fluid (IV) may be required. Should oral re-hydration be attempted, frequent small amounts of clear fluids should be used.
Clear fluids include:
- Sports drinks – Pedialyte, Gatorade, Powerade, etc.
- clear broths – Chicken Noodle Soup
How serious is Dehydration?
Complications that may occur include:
- kidney failure
- heat-related illnesses (heat exhaustion or heat stroke)
- electrolyte abnormalities