Hydration - Health and Phys. Activity Flashcards
What are the purposes of water in the body?
- cushion/protection
- water & electrolyte balance (osmotic pressure)
- carries oxygen, nutrients, hormones, etc.
- carries waste products away for excretion
- solvent for minerals, vitamins, amino acids, glucose
- functioning of our senses
- regulation of body temperature
What things may increase body temperature?
higher BMR, infectious disease, shivering, exercise
What % of metabolic heat produced during exercise is converted to heat?
60-80%
How is heat removed?
via radiation, conduction, convection, and evaporation
In sport and physical activity what would impact our ability to sweat (evaporate water)?
- current hydration levels
- humidity
- weather (heat/cold, humidity, altitude)
- uniforms or equipment
- duration and intensity
- fitness level of the person (not necessarily, but can be a factor)
What are the ways that water is lost from the body?
perspiration, respiration, urine, feces
Does metabolism produce or lose water?
metabolism can produce water
What is the adequate intake of fluids for adult males and females? Does this include only water drank?
adult males = 3.7L
adult females = 2.7L
includes all foods, beverages, and water
Is there a set upper limit for water?
no UL
Is water a reactant or product in metabolism?
product
How is water stored? (With what?)
stored in body with protein, carbohydrates, and electrolytes
Water composes what % of adult body? What does this depend on?
50-60%
depends on body composition
Water storage is regulated by what organ?
Regulated by the kidneys
What is euhydration and normohydration?
Euhydration: state of optimal total body water content as regulated by the brain
Normohydration: normal hydration
In class discussion - how do we know if we’re hydrated, and how can we monitor our hydration?
hydrated - not thirsty
monitor - looking at urine colour
When urine is at its darkest (brownish yellow), what may this indicate?
May indicate blood in urine or kidney disease
Why might the colour in toilet not be accurate of your hydration level?
Certain foods, medications and vitamin supplements may change your urine colour even if you are hydrated.
Colour will be diluted with water in the toilet.
What are the dangers of hypohydration or hyperhydration?
detrimental to performance
heat illness, sickness
lose consciousness
death
What is hyponatremia? What can this cause?
When you drink too much water without replenishing electrolytes, causing sodium/electrolyte levels in blood to be lower than normal
can cause confusion, fainting; fatal if misdiagnosed
What are practical hydration goals?
- Getting comfortable with hydration during intensity
- include 250-500ml water with each meal and snack
- consume fluids to match sweat rates or minimize drop in BW (match in vs out)
- monitor for dehydration in heat
- include 500-750ml water or fluids with recovery planning
At what % loss of body weight due to sweating can performance begin to reduce?
As little as 2%
In what type of exercise are adverse effects of dehydration (>2% loss of BW) most severe on?
aerobic endurance performance (especially in hot or humid environments)
What is the difference between voluntary and involuntary water losses?
Voluntary - urination
Involuntary - sweat
Might dehydration and water differ for a trained athlete?
Yes, trained athlete can acclimatize to heat, weather, altitude, etc.
In what situation should fluids be consumed during performance?
when exercise duration exceeds 60min (and when ambient temperature is high) - then fluid deficits during exercise may reach levels that are likely to effect performance
What was the avg. sweat rate of OHL players?
1.4-1.6L/hr
For candidates for Canada’s junior men’s hockey team? What % started hydrated? What was the avg. sweat rate?
What % of sweat loss was replaced?
over 50% started hydrated
avg. sweat rate of 1.8L/hr (goalies - 2.9L/hr)
replaced only 58% of sweat loss
Acute changes in bodyweight are a result of what?
Shift in body water
How can hydration status be estimated?
track early morning bodyweight - measured upon waking after morning pee
What is osmolality?
refers to amount, or concentration, or dissolved substances (solute) in a solution (osmol/Kg solvent)
How does osmolality relate to dehydration and overhydration?
osmolality increases with dehydration (hypertonic) and decreases with overhydration (hypotonic)
number of solute particles per liter of solution