Ch 11: Hydration Flashcards
Purposes of Water
Constitutes a great percentage of Body Mass
Helps fill the spaces inside and outside the cells
Continually being formed and broken down during metabolic pathways in the body
Found in all major vessels
Water contained inside the cell membrane; Makes up 2/3 of the body’s water
Intracellular Fluid
Water outside of the cell; b/w the cells and transported throughout the body via veins, arteries and capillaries.
Extracellular Fluid
Primary factor that determines what space body water will occupy
Sodium and Potassium
Major Extracellular Solute
Sodium
Major Intracellular Solute
Potassium
Molecules that contain a Positive or Negative Charge
Electrolyte
Describes the concentration of Solutes in a Liquid
Osmolality
Primary Regulator of Hydration Status
Osmolality of ECF (specifically Plasma Osmolality)
Cause of the majority of fluid and electrolyte shifts in the body and between compartments
- Food and Beverage Intake
- Urine Loss during Recovery
- Sweat during Exercise
Physiological factors such as high Osmolality or Low Blood Pressure, which prompt Sodium and Water appetite
Dipsogenic Signal
Specialized nerves that can sense change in pressure in the heart and blood vessels
Baroreceptors
Most significant influence to thirst for water
Regulated by ECF Osmolality
A solution with a Lesser concentration of Solute (Fresh water vs Salt water)
Hypo-Osmotic (Sweat)
Key Driver of thirst
Plasma Osmolality
The rate at which fluids and their contents pass through the stomach via the pyloric sphincter and into the small intestine
Gastric Emptying Rate (GER)
Hydration efficiency was calculated as the volume of urine produced over a 4-hour period following ingestion of 1 liter of each beverage type
Beverage Hydration Index
Best defense against experiencing a heat-related illness
Abstention from overexertion in hot external environmental conditions or microenvironments
Key adaptations that improve tolerance to exercise in hot environments.
An earlier onset of sweating and greater sweat rate
The movement or flow of air over an object
Convection (Wind, movement against air)
Normal Hydration status
Euhydration
Determinants of Sweat Evaporation Rate
Heat (higher temps increase rate of sweat evaporation)
Humidity (Environments with lower humidity increase the rate of sweat evaporation)
Convection
Factors involved in Heat Illness/stroke
Hydration
Environmental Conditions
Level of Exertion
Training Status
Body Composition
Clothing
Effects of Hydration status on Exercise Performance
Cardiovascular and Thermoregulatory Function
“as desired” and refers to eating or drinking as you are normally driven to (i.e., not purposely overeating or undereating).
Ad Libitum
Clinical Dehydration is defined by what?
Plasma Osmolality of Sodium, not by total body water
In the Laboratory, how is Euhydration defined
urine solute concentration (e.g., urine-specific gravity)
Hydration plan 3 steps
Establish Sweat Loss Volume from routine exercise sessions and determining if clients begin training in a Euhydrated status
Once this information is established, Fluid prescription during and between exercise bouts can be developed
What do you need to determine client sweat rate?
A reliable digital scale. Clients should weigh themselves nude. Client should weigh themselves before and after the workout. Workout should last an hour. Avoid using the restroom
Fluid Intake should not exceed
Sweat loss volume
Fluid deficit should not exceed
Less than 2% body mass
Miscalculation of sweat loss
Underestimation
A potentially serious medical condition in which the plasma Sodium falls below 135 mmol/L, usually the result of fluid intake greatly exceeding sweat losses during prolonged exercise
Exercise Associated Hyponatremia (EAH)
Exercise Associated Hyponatremia (EAH) effects
Hyperhydration dilutes Extracellular Sodium which allows an Influx of of water in the Intracellular space which can lead to cells in the brain stem rupturing leading to coma or death. During exercise, blood flow to the kidneys is greatly decreased which does not clear existing fluid
Symptoms of Severe EAH
Coma and Seizures; Death
Mild Symptoms of EAH
Sweat Loss Volume Kilograms Equation
Initial Weight (kg) - Post-exercise weight (kg) + Fluid Consumption (kg) - Urine volume (kg)
EAH Symptoms
Weakness, Cramping, Vomiting, Disorientation and Confusion
Most popular methods to determine Pre-Exercise Hydration
Changes in Body Mass and Urinalysis
Body Mass in detection of Hydration Status
Record Morning Body Weight after voiding for a 3 day period and use a 1% decrease from a 3 day body-mass mass as a marker for Hypohydration
Aspects of Urinalysis to gauge real time hydration status
Osmolality, Color and Specific Gravity
Urine Color Chart
1-3 Hydrated, 4 - 8 Dehydrated
Measurement that represents a ratio of solutes in Urine compared to Distilled Water
Urine-Specific Gravity (USG)
Manual Refractometer
Simple Hydration Advice
Encourage 500 mL of water before bed and another 500 mL 2 hours before exercise
Fluid strategies for endurance athletes
Place fluids along routes, place routes that pass water fountains, carry hydration packs, hand bottles, Sweat-loss assessment
Fluid and Electrolyte intake between two consecutive training sessions or competitions
Recovery Hydration
Key to Recovery Hydration
Replace Sweat-loss fluids and maximize the retention of these fluids before the next training session
ACSM Guidelines for Recovery Hydration
When less than 12 hours, Athletes should replace 150% of their sweat loss via beverage fluids
Supports Fluid Retention by decreasing Relative Urine Retention
Sodium, Protein and Carbohydrates
Five Steps for Developing a Hydration Strategy
- Establish a Sweat-Loss Volume
- Consume 500 mL before bed and 500 mL 1-2 hours before exercise if sweat-loss volume is expected to be Less than 3%
- Prescribed Fluid intake if Above 3%; Provide opportunities for fluid intake Ad Libitum
- Avoid exercise with extreme thirst of Dark Urine
- Educate clients with Specific Gravity above 1.025 to consume 110 -120% Sweat Loss. Snacks
Signaling mechanism that triggers thirst from a significant loss of total body water from sweating
Baroreceptor
1.5 kg equals how many liters of sweat
1.5 L (Kg roughly equals Liters)
Greatest concentration of Intracellular Fluid
Potassium
