Around 60% of the human body is made up of water. It is present within cells, blood vessels, and interstitial spaces. Your body has an efficient system for managing water levels, as it makes you thirsty to increase fluid intake when necessary. Throughout the day, the human body loses water through various bodily functions such as sweating, urinating, and breathing. However, you can replenish the lost water by drinking fluids. Failure to replace lost fluids can lead to dehydration, which can have serious consequences. Here is all you need to know about dehydration. 

What is Dehydration?

Dehydration occurs when the body doesn't have enough water, leading to a shortage of fluids in blood vessels and cells. Thirst is the body's natural mechanism for signalling inadequate hydration. If you feel thirsty, it means that you're already slightly dehydrated and this can cause symptoms to manifest.

Symptoms of Dehydration

Even a small loss of 1.5% of the body's water can result in symptoms. Physical symptoms of dehydration include:

• Headache
• Delirium
• Tiredness (fatigue)
• Weakness
• Dizziness
• Light-headedness 
• High heart rate but low blood pressure
• Dry mouth and/or dry cough
• Loss of appetite but craving sugar
• Swollen feet
• Flushed (red) skin
• Muscle cramps
• Constipation
• Heat intolerance or chills
• Dark-coloured urine

Dehydration doesn’t just affect you physically, it has various mental and emotional symptoms. These include:

• Confusion 
• Forgetfulness
• Anxiety
• Crankiness

Causes of Dehydration

Dehydration can occur due to various reasons. For instance, you sometimes don't drink enough fluids due to being busy or sick or even during travelling, camping or hiking. Some of the other causes of dehydration can be:

1. Diarrhoea and Vomiting

Diarrhoea, especially if severe and acute, can cause a significant loss of fluids and electrolytes very quickly. If your diarrhoea is accompanied by vomiting, it can exacerbate the problem.

2. Fever

Fever, especially if accompanied by diarrhoea and vomiting, can lead to dehydration. The higher the fever, the greater the risk of dehydration.

3. Excessive Sweating

Vigorous activity can result in fluid loss through excessive sweating. Failure to replenish fluids as you go along can lead to dehydration. High temperature and humidity increase sweating and thereby fluid loss.

4. Increased Urination

Frequent urination can be a result of uncontrolled or undiagnosed diabetes or certain medications such as diuretics and blood pressure drugs. All these conditions can increase urine production and lead to dehydration.

Complications of Dehydration

Dehydration can have severe complications, such as:

1. Heat injury

If you don't consume enough fluids during vigorous exercise or in hot environments, then you may suffer from heat cramps, heat exhaustion, or even life-threatening heatstroke.

2. Urinary and kidney issues

Repeated or prolonged episodes of dehydration can result in kidney stones, urinary tract infections, and kidney failure.

3. Seizures

Electrolytes, like sodium and potassium, transmit electrical signals between cells. An electrolyte imbalance can result in involuntary muscle contractions and, in some cases, loss of consciousness.

4. Hypovolemic shock

Also known as low blood volume shock, this is a severe and potentially life-threatening complication of dehydration. A decrease in blood volume causes a drop in blood pressure and oxygen levels in the body.

How to Prevent Dehydration?

There are some steps you can take to keep dehydration at bay. These include:

• It's important to drink plenty of fluids and consume foods with high water content, such as cucumbers, watermelon, and almost all fresh vegetables. 
• In cases of vomiting or diarrhoea, it's crucial to start drinking extra water or an oral rehydration solution (ORS) to prevent dehydration. Waiting until dehydration occurs can worsen the condition.
• When engaging in strenuous exercise, it's recommended to start hydrating the day before. Producing clear, dilute urine is a sign of good hydration. While exercising, replenish fluids regularly and continue drinking fluids afterwards.
• During hot or humid weather, try drinking more water or other fluids such as coconut water, lemon juice or bael fruit juice, to regulate body temperature and replace fluids lost through sweating. In cold weather or at higher altitudes with dry air, extra water is necessary to combat moisture loss.
• Minor illnesses, such as influenza, bladder infections, or bronchitis, can cause dehydration in older adults. During illness, it's important to drink extra fluids to avoid dehydration.

It's vital to stay properly hydrated at all times to ensure the proper functioning of your mind and body. It's also necessary for ensuring your overall health and well-being. If you experience any of the symptoms mentioned above,

Consult Apollo's Expert Doctors

Medically reviewed by Dr Sonia Bhatt.