Fluid & Electrolyte Balance HLTH 120N; Lecture 9

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.

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

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 .

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

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

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

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

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

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

Fluid Function Recap

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

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

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

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

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

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

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

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 .

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:

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

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

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

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

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

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 .

Urine Color Chart

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

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

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

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

5 lifestyle changes 5-10%

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 _________________

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

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?