Water plays a key role in body temperature regulation. When we begin to overheat, we sweat. By sweating, we lower our body temperature through evaporative cooling. Because sweat is mostly made up of water, when we’re dehydrated, we’ll stop sweating and can quickly overheat. Anyone who’s ever suffered heatstroke understands the importance of hydration on a hot summer’s day!
It may sound silly, but if someone is outright bawling and they have nothing but dry eyes to show for it, then there’s a good chance that they're dehydrated. Tears are actually used to clean and lubricate the eyes. Although tears for crying differ in composition from tears used for real lubrication, all tears contain water. So, if we’re low on H2O, we may stop producing tears.
When we’re properly hydrated, water moves from our cells into the bloodstream in order to maintain the appropriate amount of blood in our blood vessels and to regulate blood pressure. With chronic dehydration, blood volume and blood pressure may drop such that the oxygen content of blood drops as well. Without proper oxygen, our muscle and nerve functions slow down and we become easily fatigued.
With a drop in blood volume and pressure, dehydration can also cause us to feel lightheaded, faint or become dizzy. One of the key signs of dehydration-related dizziness is a sudden rush of lightheadedness when we stand up too quickly, a condition called orthostatic hypotension.
Proper hydration is extremely important for the active male. Although it’s not entirely understood how dehydration affects muscle function, it’s probably related to an imbalance of electrolytes. Electrolytes like sodium and potassium are electrically charged ions that our muscles use to contract. If we’re chronically dehydrated, we may develop a lasting electrolyte imbalance that can lead to continuous muscle cramping or spasms during or after exercise.
The heart needs a healthy and normal body environment in order to function properly. Because the heart is a muscle like any other, with reductions in blood flow and changes in electrolyte concentrations due to dehydration, the timing of our heart can be affected and we may begin to experience abnormalities in the heart’s beating pattern (called palpitations).
Dehydration reduces the elasticity of the skin (also known as "skin turgor"). Doctors may actually use skin elasticity as a quick check of dehydration through a special test called the "pinch test." Basically, the skin on the back of the hand is pinched and pulled upwards, and then released. Skin with normal turgor snaps rapidly back to normal while skin with decreased turgor remains elevated and drops slowly. Although this isn’t the best test of dehydration, the elasticity of the skin is still a good sign to tell us if we’re hydrated.
When we’re healthy, the food we eat moves freely through our colons. The colon will absorb water from foods we've eaten while leaving behind waste. The waste left behind is what forms the stool itself. Constipation occurs when the colon absorbs too much water or when muscle contractions are slowed. When we’re dehydrated, the colon will try to conserve water and will absorb too much water from our food, causing our stools to become hard and dry. The result is constipation.
As blood pressure falls and tissue dries out in the dehydrated individual, the kidneys will kick into action and try to conserve water by concentrating the urine or by stopping the production of urine entirely. As the urine becomes more and more concentrated, its color will become darker and darker until it reaches shades of dark yellow or even amber.
The No. 1 sign that you’re not sufficiently hydrated is probably the most obvious: you’re thirsty. The mouth dries out and your tongue becomes slightly swollen as your body cries out for hydration - signs that should not be ignored. The best way to avoid dehydration is simply to drink water whenever thirsty. If, however, you’re drinking enough water and you’re still noticing signs of dehydration, then some other underlying condition may be source of your problem.
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Even a slight change in our water levels can lead to dehydration. And if we constantly fail to top-up on H2O whenever we lose it (and we lose it a lot), then we may become chronically dehydrated. Thankfully, your body will let you know when this happens