Being a paediatric intensive care retrieval service, we have recently dealt with previously normal hyponatraemic children presenting with abnormal neurology and seizures. A 1?year?old child presented with status epilepticus after a 2?day history of vomiting, during which hypotonic fluids were given. The child required intravenous lorazepam and one dose of rectal paraldehyde to terminate the seizure, and was intubated, ventilated and transferred to a regional paediatric intensive care unit. The concetration of serum sodium on attendance was 116?mmol/l. The child was subsequently fluid restricted for 48?h.

Depending on age and sex, about 40 to 60% of body weight is water (younger people retain more water). Any substantial drop below the normal amount results in a potentially serious medical condition called dehydration. The body routinely loses about five pints of water a day through urination, fecal matter, sweating, and water vapor exhaled during respiration. The fluids people drink combined with water in food usually make up for that loss.
Ignoring thirst and excessive sweat could lead to heat exhaustion. Severe dehydration can result from extreme diarrhea or any other disorder that causes rapid water loss. In extreme cases dehydration can lead to shock and even death.
Parts affected: Every cell in the body contains water. Both the amount of water and the concentration of electrolytes( important chemicals; including sodium and potassium, used as cellular signals) are important to normal bodily functions. Sweating and diarrhea do not only remove water but also lower the amount of electrolytes in the blood. Among the more immediate effects of the loss of electrolytes in serious dehydration are problems with the circulatory system (rapid heartbeat) and nervous system (loss of consciousness, shock).
Related symptoms: Dehydration is often accompanied by excessive thirst, weight loss, and dry mucous membranes. With heat exhaustion the patient sweats profusely, turns pale, and has cool skin, rapid breathing, and a high pulse rate. The person may be dazed and confused, but usually remains conscious.
Associations: Dehydration is a symptom of various disorders that result in excessive fluid loss, including cholera, dysentery, and other forms of severe diarrhea. Some of these diseases stimulate vomiting as well as diarrhea, which makes it more difficult to replace lost fluids.
Prevention and possible actions: Drinking fluids at regular intervals while working or exercising in hot weather can help prevent heat exhaustion and other problems associated with mild dehydration. Administering fluids that contain electrolytes can prevent damage from severe dehydration caused by cholera or other forms of severe diarrhea.

Some conditions and climates require us to have a larger input of water than what we are accustomed to, like in hot summers or after a dehydrating exercise or job that make you sweat a lot.
If we can’t make up for the water loss from our body we tend to feel week and dizzy. If this condition is sustained long enough, we might lose consciousness, which is not healthy for the body because it indicates that some organs are malfunctioning and will soon face a lot of complications. Unconsciousness is due to hypotension, which is low blood pressure, because the lesser the blood circulates and reaches the brain, the lesser is amount of oxygen delivered there, causing headache primarily, then unconsciousness, which can lead to DEATH if sustained long enough!!

*Learn More about dangerous side effects of dehydration*

In normal conditions, the body loses 2500 ml per day of water on average through urination, sweat, feces, and insensible loses via skin and lungs. However our input is divided between drinking fluids, foods, and metabolism. Drinking fluids brings back 1500 ml of the lost 2500 ml, while foods contributes to half of that (750 ml) and metabolism 250 ml, on average.

When performing exercises for an hour and a half (90 minutes) or more, it would be advisable to drink water from time to time to keep the body hydrated to maintain the right bodily functions needed for the workout. However,massive intake of water before, during, and after exercise is not healthy. In fact,  digestive system does not function as effectively as it normally does during exercise if large amounts of water and food are in the stomach which can lead to vomiting, nausea, and in some cases bleeding from the nose.

During and after exercise the body doesn’t only lose water, it also loses electrolytes like sodium. Thus, it is more efficient to drink bevereges that contain these fluids such as Gateorade. Such drinks are most preferably consumed by endurance athletes like marathon runner, bikers, swimmers..etc