Water is one of life's essentials on Earth, and when it comes to health, it's needed to keep balance and the body healthy overall. But many people don't drink enough water, especially hospital patients, which causes health problems. This article will explore a lot about body fluid balance, how and why it’s measured, the importance of measuring fluid balance precisely, and the health effects of dehydration and excess water too.
What is fluid balance?
Fluid balance is the term used to describe balancing the intake and output of fluids from and to the body. This balance helps metabolism work correctly. Fluids make up 52% of total body weight in women and 60% in men. Electrolytes (ions) in blood plasma also need to be balanced properly, especially sodium, potassium, and magnesium. Too much or too little of these electrolytes can cause irregular heartbeats.
Two-thirds of total body fluids are inside cells, and the remaining third is fluid outside the cells. This outside fluid splits into plasma and interstitial fluid. There’s also a third space called "transcellular fluid," found in body cavities like cerebrospinal fluid and synovial fluid. Even though these fluid parts are separate areas, water and electrolytes constantly move among them.
Fluid movement:
Fluid movement means the fluid circulating between compartments by diffusion. This random movement keeps going until the fluid is evenly spread. But how do fluids form in tissues?
The amount of water inside cells is set and spread by hydrostatic pressures. This happens through blood pumping in the heart, gravity's effect on blood inside vessels, and osmotic pressure created by molecules in the solution. This osmotic pressure is due to proteins in the solution, called oncotic pressure, and the osmotic pressure from electrolytes dissolved in the solution is called crystalloid osmotic pressure. Usually, proteins are big enough in healthy people that they can’t pass from capillaries into interstitial fluid.
Maintaining fluid balance:
The total volume of fluids in the body does not exceed 1%. So, it is important to pay attention to how fluid balance works in the body. Usually, fluids are obtained by drinking water and also through food. Water is lost through urine, stool, sweat, and breathing. Water lost through stool, sweat, and evaporation can't be regulated the same way by the body. These losses are affected by diet, illness, and environment. When fluids are low, the adrenal glands release aldosterone hormone which triggers sodium reabsorption in the kidney tubules and collecting ducts. This sodium reabsorption then causes water to be reabsorbed in the collecting ducts, helping keep balance.
Dehydration:
Dehydration happens when you use up or lose more fluids than you take in. There's not enough water or fluids in your body for normal function. If you don't replace lost fluids, you will get dehydrated. Anyone can get dehydrated but it's serious mainly for small kids and elderly people.
Mild dehydration symptoms include:
- Reduced body functions
- Lower physical performance
- Headache and fatigue.
Dry skin can cause a drop in blood volume leading to the following:
- Low blood pressure
- Weak heartbeats
- Cold hands and feet
- Reduced urination frequency
These dehydration symptoms are the start of a problem with low blood volume in the body, which can cause organ failure and sometimes death.
Causes of dehydration:
- Diarrhea, vomiting: This means diarrhea that comes out suddenly and strongly. It can cause severe water loss and fever. In general, the higher the fever, the worse the dehydration. The problem gets worse if there is fever along with diarrhea and vomiting.
- Excessive sweatingIf you do intense activity and lose fluids without drinking water during it, you get dehydrated. Hot and humid weather also increases sweating and fluid loss.
- Sometimes dehydration happens from simple reasons like: Not drinking enough fluids due to illness, being busy, or not having safe drinking water when traveling, sightseeing, or camping.
