How Does Dehydration Affect Our Bodies?


We often take the recommendations of drinking enough water throughout the day too lightly. It’s high time we ensure to keep ourselves hydrated by sipping water every now and then, especially now when heatwaves are reaching all-time highs all across the world. Medical experts are emphasising the dangers of dehydration and its effects on the mind and body now more than ever. Dehydration can severely impair a person's cognitive performance in as little as two hours, according to new research, affecting the ability to focus, perform executive functions, and control motor coordination. To better understand dehydration and its effects on the body, let's look at the causes and symptoms, as well as some preventative measures.

What Is Dehydration?

Dehydration is the result of an excessive loss of water in the body. This usually happens when a person loses more than 2% of their bodily fluids. While the body naturally loses fluid throughout the day through sweat, bowel movements, urination, and other daily activities, dehydration can set in quickly if the water levels are not replenished. This condition can impair, if not wholly prevent, the body's ability to carry out its essential functions, leading to serious health complications.

Causes Of Dehydration In The Body

Some prevalent causes of dehydration include:

  • Sweating Excessively: Sweating is the body's natural cooling mechanism, releasing fluids to keep the body temperature stable. Prolonged exposure to heat and vigorous exercise causes you to sweat more, which causes you to lose more fluid.
  • Certain Medications: Medications such as diuretics, antihistamines, blood pressure medications, and antipsychotics, can raise the risk of dehydration by encouraging frequent urination.
  • Vomiting or Diarrhoea: Vomiting and diarrhoea are the most common cause of dehydration, as they cause a rapid loss of water and electrolytes.

How Dehydration Can Affect The Body

If left untreated, dehydration can lead to serious complications such as the following:

  • Low Blood Volume: Low amount of blood in the body leads to a drop in the blood pressure and a reduction in the amount of oxygen that reaches the tissues. This can cause fatal complications.
  • Seizures: Dehydration leads to an imbalance of electrolytes that can cause seizures which are often serious.
  • Kidney Problems: Dehydration can lead to kidney stones, UTIs (urinary tract infections) and in some severe cases - kidney failures.
  • Heat Injury: Heat injuries that are caused by dehydration include cramps, heat exhaustion and even heat stroke.

Who Are At High Risk Of Dehydration?

  • People With Chronic Illnesses: People suffering from chronic illnesses such as diabetes or chronic kidney disease (CKD) are at higher risk of suffering from dehydration.
  • Athletes: Whether you are a professional athlete or enjoy working out outside, you must stay hydrated. This is especially important during the hot, humid months, as exercising in this weather can raise your body temperature and necessitate the consumption of more fluids.

How Does Dehydration Affect The Body And Mind?

Water makes up roughly 60% of the human body, hydration is critical for regulating bodily functions. In addition, water is used by the body to perform a variety of specialised functions, such as protecting organs, flushing out waste and toxins, and transporting nutrients and oxygen to cells.

Thus, limiting your body's access to water can have a significant impact on its ability to perform these functions, lowering your internal sodium and electrolyte levels and causing physical and cognitive impairments. This can make it difficult to perform tasks that require attention, motor coordination, and executive function. This is why you should keep track of your daily fluid intake and look out for signs of dehydration.

What Are The Signs & Symptoms Of Dehydration?

Thirst is a symptom of most mild cases of dehydration; however, it is not always a reliable indicator. Most people don't realise they're thirsty until they're already dehydrated. That is why you should drink more water throughout the day, especially if you are sick or spending time outside. However, depending on a person's age, health, and body, most signs and symptoms of dehydration can vary greatly.

  • Infants & Toddlers: Dehydration in small children and infants can be challenging to detect because they cannot communicate their discomfort effectively. Dehydration symptoms in children frequently include - Sunken eyes and cheeks, dryness of the mouth and tongue, no urination for at least three hours, and irritability.
  • Adults: Symptoms of dehydration in adults include extreme thirst, dark-coloured urine, dizziness, fatigue, headaches, confusion, less frequent urination, nausea.

Medical Treatment

While most cases of dehydration can be reversed by increasing fluid intake, severe cases may necessitate immediate medical attention. Your doctor may order a blood test and urinalysis to determine the extent of dehydration. Nonetheless, replacing lost fluids and electrolytes is the most effective way to treat dehydration. This is frequently administered intravenously (through a vein) in emergency rooms (ERs) for maximum body absorption and speedy recovery.

Tips For Preventing Dehydration

  • Hydrate before, during, and after any physical activity
  • Monitor your hydration status based on your thirst level and the colour of your urine; darker urine may indicate dehydration
  • Carry a reusable water bottle with you at all times and sip from it frequently throughout the day
  • Keep water bottles at every corner of your house and take a sip from the bottle whenever you spot one
  • If you are too busy with work, set reminders on your phone and drink water every time the timer goes off
  • Consume a well-balanced diet rich in grains, greens, protein, fruits, and vegetables

Learn more about our Department of General & Internal Medicine here.

Dr Ahmer Ali Khan

Consultant – General Physician

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