About Dehydration
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What is dehydration?

Dehydration results when water intake is less than the water output from our body. Up to 75% of the body’s weight is made up of water, mostly found within our body’s cells. It is important we keep a balance of these fluids, as adequate hydration is essential for our body’s ability to function. There are many ways we lose fluids naturally. As we breathe humidified air leaves the body, as we sweat to cool the body and from urination. Drinking a significant amount of water to replace the natural loss of fluids on a regular basis is recommended as part of your daily routine.

What causes dehydration?

Dehydration can be caused by vomiting or diarrhoea. A significant loss of body water, and to varying degrees electrolytes, results in dehydration. Other causes include excessive sweating (from exercise or illness), increased urine output (from diuretics), fever or decreased fluid intake because of nausea or loss of appetite.

Signs and symptoms of dehydration

Common signs of dehydration include thirst, lethargy, and drowsiness, a dry mouth or tongue, sunken eyes, no tears when crying or a decrease in urine output. When children are ill they often show signs of fatigue, restlessness and irritability which can make it difficult to increase fluids. Signs of a child becoming dehydrated are similar to an adult; however tend to appear more rapidly. This is because they may lose more fluid quickly. Young children, babies and the elderly are a particularly high risk group for dehydration.


Diarrhoea is a consequence of irritation to the intestinal lining and can be accompanied by vomiting. The irritation may be caused by bacterial or viral infections (although these are not the only causes of diarrhoea). Diarrhoea may cause the body to lose far more fluid and essential mineral salts than normal which can lead to dehydration.

Why are electrolytes important?

Electrolytes including sodium, chloride and potassium are lost during episodes of diarrhoea. These mineral salts are required by the body to help regulate nerve and muscle function, and to maintain fluid balance. In order for the body to function normally, it must keep the correct fluid balance within the cells, the space around the cells (interstitial fluid) and in the blood. Electrolytes play a role in maintaining this fluid balance.

Oral rehydration therapy

The World Health Organization (WHO) and the United Nations International Children’s Emergency Fund (UNICEF) currently recommend the use of oral rehydration therapy (ORT) for the prevention and treatment of dehydration due to diarrhoea. Oral rehydration therapy has been described as one of the most important medical advances. Having an appropriate balance of electrolytes in an oral rehydration solution is of the utmost importance to help stop dehydration.

Dehydration and heat: how hot weather can be dangerous

In order to stay healthy, our body temperature needs to stay at approximately 37⁰C. Usually, the body cools itself by sweating, which accounts for up to 80 percent of the body’s heat loss. When you don’t drink enough fluids during hot weather, you may become dehydrated. This causes a decrease in sweat production and your body temperature will keep rising as your body struggles to cool down. This can lead to heat‐related illnesses.

Heat‐related illnesses

Heat stroke is the most serious heat‐related illness and occurs during times of extreme exposure to the sun. In cases of heat stroke, a person does not sweat enough to reduce their body temperature normally. The condition can develop quickly and is a medical emergency requiring immediate treatment.

Other heat-related illnesses include:

  • heat rash
  • cramps
  • dizziness
  • fainting
  • heat exhaustion
  • heat stroke
  • potential worsening of any existing medical conditions.

How common is dehydration due to extreme heat?

Dehydration is a very common heat‐related illness that can be life threatening if left untreated. Although anyone can become dehydrated and go on to develop heat‐related illnesses, certain people are more at risk than others. The groups that are most susceptible to dehydration include:

  • People working or exercising outside in extreme heat and/or humidity: when the air is humid, sweat can’t evaporate and cool you as quickly as it normally does. This can lead to an increase in body temperature and an increased need for fluids.
  • People with chronic illnesses.
  • Infants and children: This is due to their small body weights and high turnover of water and electrolytes.
  • Elderly people: As we age our bodies are less able to conserve water, thirst becomes less acute and we are less able to respond to changes in temperature.

It is predicted that the number of cases of heat‐related illness will become more prevalent under the influence of global warming. Fortunately, dehydration and heat‐related illness is usually preventable. Your response to a heat wave is a key factor in managing the development of heat related illnesses.

Dehydration and Travel: how does dehydration occur when travelling?

Dehydration can occur more easily while you’re travelling for several reasons. Firstly, you may not drink enough fluids simply because you don’t have access to clean and safe drinking water in the area where you are travelling. Or you may be too busy and forget to drink fluids. Dehydration caused by air travel is particularly common and is due to low humidity levels in aircraft cabins. Finally, travellers’ diarrhoea is a leading cause of dehydration in people who travel internationally. In most cases, the diarrhoea occurs in people who travel to areas with poor water and food hygiene.

What are the signs and symptoms I should be aware of?

Remember that heat exposure and exercise increases the risk of dehydration. It pays to be aware of this when holidaying, for example when walking and sightseeing.

Watch out for the following symptoms while travelling, as they could mean you are suffering from dehydration:

  • Headache
  • Dizziness or feeling lightheaded
  • Decreased urine output
  • Dry skin
  • Tiredness or sleepiness
  • Thirst

How can I prevent dehydration when travelling?

Planning ahead is key when it comes to dehydration prevention while travelling. Take extra water with you when travelling outdoors or anywhere where activity levels and heat exposure will increase fluid losses. Avoid drinking alcohol, especially in warm weather. Alcohol increases fluid loss from the body and also impairs your ability to sense the early symptoms of dehydration. Dehydration during air travel can be prevented by sipping from a bottle of water throughout the flight, drinking a rehydration formula is even better. Avoid caffeinated drinks such as coffee, tea and colas as these can also have a dehydrating effect.

Traveller’s Diarrhoea/Gastroenteritis

Traveller’s Diarrhoea (TD) is caused by infectious agents and most cases begin abruptly. The illness results in increased frequency and volume of stool. Typically, a traveller experiences 4‐5 loose or watery bowel movements a day. Other symptoms may include nausea, vomiting, cramping, bloating, fever, urgency and fatigue. Dehydration may result from the diarrhoea so it’s important to consume oral rehydration drinks to replace lost fluids and electrolytes. If symptoms persist, see a healthcare professional.

Staying hydrated during sport: Perform at you maximum level

Dehydration refers to a state where there is an inadequate amount of fluid in the body. People who participate in endurance sports or long workouts are particularly at risk of becoming dehydrated quickly. A person is considered dehydrated when they have lost more than 2% of their body weight during exercise. All levels of dehydration impair physical performance, even mild dehydration. It reduces physical performance by increasing heart rate and reduces mental function and skill level. It also causes the person to have an increased exertion perception (i.e. exercise feels harder than usual and the athlete fatigues earlier).

How does dehydration occur from vigorous exercise or sport?

Dehydration during physical exercise is common, because voluntary fluid intake is usually less than fluid losses that occur from sweating. Dehydration causes negative effects on the body’s ability to function and these are magnified by increases in heat stress, exercise duration and exercise intensity. Drinking enough fluids during sport helps to minimise the decrease in blood volume and blood flow to muscles that occurs when a person is dehydrated. Staying hydrated also minimises the rise in core body temperature that happens when we exercise.

What are the signs and symptoms of dehydration during sport?

Symptoms of dehydration during exercise may include:

  • A dry or sticky mouth
  • Decreased or no urine output
  • Weakness
  • Dizziness
  • Concentrated, dark coloured urine
  • Skin that doesn’t bounce back quickly when pinched

How can I help to prevent dehydration during sport or physical exercise?

In order to prevent dehydration, drink plenty of water before, during and after exercise. This is particularly important in hot weather or during intensive activity. Take a drink bottle with you and try to drink at least every 15 to 20 minutes during your exercise session. You can drink ReSport that includes both the electrolytes needed and a small amount of caffeine to help you stay alert. You should also avoid drinking alcohol since it increase urine output and therefore your risk of becoming dehydrated. Wear one layer of light coloured, lightweight clothing when exercising outdoors and change into dry clothes as soon as possible if they become soaked with sweat. You should also stop exercising if you feel dizzy, light headed or very tired.

Alcohol and dehydration: how does dehydration occur from excess alcohol?

Excess alcohol consumption can cause dehydration in a variety of ways. Firstly, alcohol decreases the body’s production of anti-diuretic hormone, which is used by the body to reabsorb water. With less anti-diuretic hormone available, your body loses more fluid than normal through increased urination. Drinking excessive amounts of alcohol can also cause vomiting, which depletes the body of fluids and can cause further dehydration. The effects of alcohol vary from person to person, but in general the less a person weighs the less alcohol it takes to cause dehydration or vomiting.

What are the signs and symptoms I should be aware of?

If you are concerned that you may become dehydrated while consuming alcohol, look out for the following symptoms:

  • A dry, sticky mouth
  • Sleepiness or tiredness
  • Thirst
  • Decreased urination
  • Headache
  • Dizziness or light headedness

How can I prevent dehydration if I know I will be drinking alcohol?

Drinking water along with alcoholic beverages can help to prevent dehydration. Have a glass of water before you start drinking alcohol and alternate alcoholic beverages with water throughout the evening. Drinking a glass of water before you go to bed will also help to relieve dehydration. A good alternative to water is an electrolyte solution which provides not only the water but valuable electrolytes.

How do I treat the symptoms of dehydration after I've had excess alcohol?

Even if you feel fine the morning after heavy drinking, alcohol has long lasting effects that will reduce your ability to function at your best. Electrolyte replacement solutions and broths are ideal for replacing the sodium and potassium that is lost during alcohol consumption. Drink plenty of fluids, especially rehydration drinks and try to rest as much as possible.

Staying hydrated during Ramadan: A major concern

In the Middle East, hydration during summers and Ramadan is a major concern. However, water alone cannot keep up the optimum hydration levels. As such, it is important to hydrate with water that is mixed with an electrolyte solution.

What is Ramadan?

Ramadan is the ninth month of the islamic calendar and is observed by Muslims worldwide as a month of fasting. While fasting from dawn until sunset, Muslims refrain from consuming food, drinking liquids, smoking, and engaging in sexual relations. Since no liquids can be consumed during daylight the risk for dehydration is a major concern.

How can I help to prevent dehydration during Ramadan?

In order to prevent dehydration, drink plenty of water at dawn and after sunset. This is particularly important in regions with hot weather. You can drink Natuvital Ramadan solution that includes all the electrolytes and minerals needed to keep hydrated during the day.