1. Fluid & Electrolyte Balance
HLTH 120N; Lecture 9

2. Objectives List 3 ways fluid composition varies.
Identify the 4 electrolytes and their 3 functions. Identify the other mineral essential for muscle contraction.
Indicate the 4 main functions of body fluids.
Know your recommendations for water, sodium & potassium.
Explain how to effectively hydrate to support exercise
Describe what occurs with dehydration, heat stroke, and hypertension.

3. Body Fluid The liquid portion of cells and tissues
Able to move freely, adapting to the shape of the area that contains it
About % of healthy adult body weight

4. Fluid composition varies by:
Tissue type
tissues have higher fluid content than tissues
Gender
usually have more lean tissue, so they have more
Age
With age, lean tissue is lost so body water

5. Intracelluar fluid: within the cell
of body fluid
Extracellular fluid: outside the cell
Interstitial fluid flows between cells that make up a particular tissue
Intravascular fluid is in the blood and lymph

7. Body Fluid Functions Dissolve and transport substances
Water is an excellent solvent
Water-soluble substances are easily transported in the bloodstream:
Fatty substances?

8. Fluid Functions cont. Account for blood volume
Correct body fluid levels maintain a healthful blood volume
Blood pressure when volume rises
Low blood volume = blood pressure
Kidneys help regulate blood volume and pressure

9. Blood Volume/Pressure Regulation
Renin responds to decreased pressure
Anti-diuretic hormone
Angiotensin II (vasoconstrictor)
Aldosterone
signals kidneys to retain sodium & chloride

10. Fluid Functions Cont. Help maintain body temperature
Must be within a safe range
Only sustained high heat can increase body temperature
releases heat as water evaporates to cool skin and blood

11. Fluid Functions Cont. Protect and lubricate tissues Examples:
Cerebrospinal fluid -
Amniotic fluid -
Synovial fluid lubricates -
Tears cleanse & lubricate -
Saliva moistens food for swallowing

12. Fluid Function Recap

13. Electrolytes Predominant electrolytes
Extracellular fluid: , chloride
Intracellular fluid: , phosphorus
Dissolved substances that disassociate in solution into electrically charged particles
Positive charge: ,
Negative charge: ,

14. Electrolyte Functions
Help regulate fluid balance
Cell membranes are permeable to water, not electrolytes
Electrolytes move with the help of carrier proteins, and water follows to areas of concentration
Too many intracellular solutes; cell will burst
Too many extracellular solutes; cell will shrivel
Normal

15. Electrolyte Function Cont.
Enable nerves to respond to stimuli
Nerve impulses are initiated at nerve cell membranes in response to a change in electrical charge
Sodium & potassium ensure nerve impulses are generated, transmitted, and completed

16. Electrolyte Functions Cont.
Signal muscle contractions
Muscles contract in response to stimulation of nerve cells
Influx of into the muscle causes contraction
Muscles relax after contraction once the electrical signal is complete and calcium is pumped out of the muscle cell

17. Water Supports all body functions Fluid Recommendations:
Women: Men:
Can be very individualized
Lost water must be replaced
Best Food Sources:

18. Thirst & Fluid Balance Like hunger, thirst is signaled by the with…
Increased salt & substances in blood
Reduced blood volume & pressure
Causes?
Dry mouth and throat from reduced saliva
Anti-diuretic hormone will signal the to retain water

19. Water Loss Sensible water loss Insensible water loss Significant loss
Skin (not sweating) or lungs
Significant loss
Illness, injury, high altitude, pregnancy, breastfeeding, diuretics

20. Water Balance Issues Deficiency Toxicity
One of the leading causes of death around the world is dehydration.
Hypernatremia:
Toxicity
Hyponatremia: dilution of blood sodium
Very rare; occurs mostly in

21. Sodium charge -cellular Functions RDA:
Exchanges with potassium for fluid balance, pH balance, blood pressure
Transmits nerve signals
Aids in glucose absorption
RDA:
Most Americans consume:
AHA, ADA recommend under:

22. Hypernatremia/High intake Hyponatremia/Low intake
blood pressure
Poor function
Sodium Imbalance

23. Potassium Functions: RDA: Sources Toxicitiy – Deficiency-
Fluid balance, nerve impulses
RDA:
Sources
Toxicitiy –
weakness, vomiting, irregular heartbeat
Deficiency-
weakness, paralysis, confusion, high BP

24. Chloride Functions: Best Source: Deficiency is rare
Fluid balance, nerve impulses
In the stomach as , aids white blood cells
Best Source:
Deficiency is rare

25. Phosphorus Role: Sources: meat, nuts, seeds, fish, veggies Toxicity:
Component of body’s energy source:
80% of body phosphorus is in:
Buffering agent
In the cell membrane, forms:
Sources: meat, nuts, seeds, fish, veggies
High amounts in
Toxicity:
Causes spasms & convulsions
Common in renal disease patients

26. Dehydration Fluid losses fluid intake
Causes:
Classified by % weight loss from fluids
Small losses:
Severe loss:
Sleeplessness, nausea, flushed skin, poor concentration
Untreated: cardiac arrest, coma, death

27. Fluid replacement & exercise
Consume water before, during, after
2-3 hours prior:
30-60 min prior:
During <1 hr:
During >1 hr:
Measure body weight before & after
For each lb lost, consume

28. Urine Color Chart

29. Heat Stroke Fatal heat illness Most vulnerable?
Failure of body’s heating mechanisms
Most vulnerable?
More muscle mass = greater heat production
Ability to lose heat through sweat very limited in humid environments

30. Hypertension Inability to maintain blood pressure in a healthy range
% of US adults hypertensive
Increases risk for:
Reduces brain function, impairs mobility

31. Type of blood pressure Systolic Diastolic Optimal: Pre-hypertensive:
Pressure arteries exert during contraction.
___________________
Diastolic
Pressure in arteries during
Optimal:
Pre-hypertensive:
Hypertensive:

32. Causes of hypertension
5-10% from kidney disease, sleep apnea, alcohol abuse
Over half have salt sensitivity
Blood pressure will increase or decrease based on sodium intake
Others are salt resistant
We now know not everyone will improve their blood pressure by reducing salt intake

33. 5 lifestyle changes
5-10%

34. The DASH diet Low-fat & high fiber
Encourages potassium, calcium, magenesium
servings fruits & vegetables/day
Sodium < 3g
Blood pressure lowers within __________
The lower sodium intake, the better
Also reduces risk of _________________

36. Fluid & electrolyte considerations
Neuromuscular issues:
Seizures – due to nerve impulse issues
Muscular dystrophy
Muscle cramps – involuntary spasms
Obesity
21% of calories come from beverages
Researchers believe sweetened beverages contribute to half the rise in calorie intake

37. DASH diet assignment
Create a 2,000 calorie diet meeting DASH diet guidelines… just create it, you don’t have to eat it
Enter the diet into MyDiet Analysis
(Do not include this day in your Diet Analysis project data)
Turn in the list of foods with the report of nutrients for that day
1 paragraph:
How does this diet compare to your own? Should it only be recommended with hypertension?