Chapter 6: Hydration – Impact of Dehydration

Chapter 6: Hydration – Impact of Dehydration


When a person’s body does not have enough fluid that it needs – Dehydration occurs. Dehydration can occur because there has been too much fluid lost or the person has not ingested the sufficient amount of fluid, or both. The most regular causes of dehydration involve sweating excessively, repeated urination, fever, vomiting, diarrhea and not drinking enough liquids.

Additional to the common causes listed above, dehydration can originate from some other surprising sources. These include:

  • Stress
  • Certain diets such as low carb diets or low calorie diets
  • Alcohol consumption of which is a diuretic
  • Hormones influence hydration levels especially during Menstruation
  • Any substance that may act as diuretics like prescription medications or dietary supplements.
  • Morning sickness during pregnancy often times causing vomiting
  • Breastfeeding

Signs and Symptoms of Dehydration

The signs and symptoms of dehydration can vary from slight to brutal. Slight to mild dehydration symptoms include:

  • A low Urine quantity with a much more yellowish color than typical
  • A larger thirst for liquids
  • Tension headaches or migraines
  • The feeling of being tired and/or sleepy
  • Dry mouth
  • Flaky and or dry skin
  • Feeling dizzy
  • Little to no tears if crying

If any one of the symptoms above worsens then it clearly signifies a developing situation of dangerous dehydration; indications and signs of severe dehydration could include:

  • A Fast and speedy heart rate
  • Tiredness, bewilderment, or even a coma
  • No urine output at all or a brutally decreased urine where if any at all, is produced, it is usually a dark yellow or amber in color.
  • A high internal temperature or fever
  • Dizziness or lightheadedness to the degree that it can affect a person’s ability to stand or walk normally.
  • Seizures
  • Sudden blood pressure dips when the they stand up after lying down
  • Skin that has zero elasticity or poor skin elasticity at best
  • Shock

Impact of Dehydration

Hydrating means continuous work capacity or the ability to perform physical work; or in nonprofessional terms: you will be able to work harder for a longer time if you stay more hydrated. A common misconception is to think that our hydration levels are directly dependent on how active we are, and for the most part that is very true. However, the days in which we are not as active our bodies still require consideration.

Once the effects of dehydration set in, it can negatively affect a person’s capacity to control their mood, cognition and their ability to concentrate. As just a 1.5% loss in water (which is defined as mild dehydration) leads to a state of fatigue, difficulty in remembering simple facts, a higher level of anxiety and lastly tension.

Hormones Affecting Hydration


Aldosterone is a hormone that is created in the exterior portion also known as the cortex of the adrenals. It serves a vital role in regulating blood pressure and it does this by working with the kidneys and the colon to amplify the volume of salt/sodium in the blood and the quantity of potassium that is eliminated through urination. Through the reabsorption of sodium, aldosterone also triggers water to be reabsorbed, thus increasing the overall blood volume and as a result increasing blood pressure as well. After the body’s salt/sodium levels and blood pressure return to baseline and proper hydration levels are achieved – the volume of aldosterone in the blood falls, resulting in more water being excreted in a person’s urine.

Another one of aldosterone’s indirect but vital functions is the regulation of electrolytes (sodium, potassium and hydrogen) in the blood. This function is necessary in maintaining a proper blood pH level.

ADH – Anti-Diuretic Hormone

Special nerve cells located at the bottom of the brain called the hypothalamus produce another important hormone called Anti-Diuretic Hormone or ADH. The hormone is released into the bloodstream from the pituitary.

Just like Aldosterone, ADH helps to control blood pressure. However, it does so through a different set of means by acting on the blood vessels and kidneys. It does so making sure the fluid volume of the blood is sufficient through the elimination of water that is excreted through the urine. The specific way that ADH does this is by letting water from the urine back into the body, making its way to an exact region of the kidney. This then results in extra water getting back into the blood which then causes the urine concentration to rise and the amount of water lost to be reduced. When large amounts of ADH are produced the hormone will cause blood vessels to tighten and become narrower and this results in an increase in blood pressure. Dehydration or a lack of body fluid can only be restored by increasing water intake.

If the level of salts/sodium in the body drops to an unusually low level, the body experiences something called hyponatraemia. A dangerous condition where the body actually drowns in too much water as it is not able to be properly absorbed into the cells. Thirst, nausea, vomiting and pain also signals the release of ADH as it acts to maintain the volume of water in the bloodstream when the body is experiencing a high level of stress or possible injury. An important point to take note of is that alcohol will prevents the release of ADH of which will cause an increase in urination possibly resulting in dehydration.


Electrolytes are minerals that have a positive or negative charge. They are mostly contained in the body’s fluids (blood and urine). By obtaining the proper balance of electrolytes in the body’s internal blood makeup aids in movement and contraction of muscles and multiple other activities. When sweating occurs, electrolytes occupy a vital role in keeping water levels maintained both inside & outside of cells so that your muscles and organs do not fail you. The list of primary electrolytes include sodium, calcium, potassium, chlorine, phosphate and magnesium. The body absorbs them from the liquids and foods that we ingest.

Just like anything else in the body, the amounts of electrolytes can become too low or too high and most commonly occurs when the volume of water in the body changes either resulting in over hydration or dehydration. The most common reasons include pharmaceuticals, excessive sweating, diarrhea, vomiting, or kidney problems. Most problems with electrolyte levels centers on the improper levels of sodium, potassium or calcium.

Naturally, as the body sweats it loses both fluid and electrolytes. If the body is not hydrated properly or you begin to exercise without being properly hydrated, and/ or you don not stay properly hydrated during your activity, dehydration can occur because of the act of sweating.

Replacing electrolytes through proper supplementation and drinking facilitates the replenishment of the body’s mineral losses; in addition consuming electrolytes helps to maximize the water that the body does take in, which is a vital component to maintaining an adequate hydration level. Any beverage that contains a good amount of sodium, potassium, magnesium, and calcium can help the body hold onto its liquids and balance fluid levels properly – contributing to a higher level of performance. Thirst is always the first indication that the body may be dehydrated. Muscle cramps and fatigue are some of the more extreme after effects of dehydration and as little as a 2% loss in water levels in the body can result in a significant decrease in performance.


© FBBC University 2023. All Rights Reserved

Privacy Policy | Terms and Conditions