Lecture 3 ppptx Flashcards
How many ml of H20 per kcal of Energy intake?
1ml H20/kcal of E requirements
Match the definition with the terms:
\_\_\_ Intracellular (ICF) \_\_\_ Extracellular (ECF) \_\_\_ Interstitial \_\_\_ Intravascular _c_ Transcellular
a. All the water outside cells
b. Water found in plasma (medium in which blood cells are suspended)
c. Water present in the gut, urinary tract and cerebrospinal fluid
d. Water found around the cells and outside of blood vessels
e. Includes all water enclosed with cell membranes
Which three of these make up the ECF?
1. \_\_e_ Intracellular (ICF) \_\_a_ Extracellular (ECF) \_\_d_ Interstitial \_\_b_ Intravascular * _c\_\_ Transcellular
2.
Interstitial
Intravascular
Transcellular
TBW = ___% ECF + ___% ICF
60% ECF and 40 % ICF
there a difference in total body water content between genders?
If so, Does this play a role in thermoregulation and hydration status during exercise?
Yes, slightly.
It can
For every __kcal of mechanical work, ___kcal of heat are produced in skeletal muscle
1:4
When is no change in body temp?
When is there an increase?
How is this regulated?
When heat loss = heat production
When heat loss < heat production
Changes sensed in hypothalamus.
Normal range for body T° is ?
At body T° of ~____°C, central fatigue begins to set in
–> What are some physiological responses to this?
36-38°C
- 5°C
- -> inc catecholamines (EP, NE) (+) breakdown muscle glycogen
- -> increase RPE, decrease performance capacity
excessive sweating, nausea, dizziness, cool/clammy hands, muscle aches, weak and rapid pulse
Are signs of heat exhaustion or heat stroke?
Exhaustion
No sweating, red skin, throbbing headache, strong rapid pulse, loss of consciousness or altered mental state. Is sign of heat exhaustion or heat stroke?
Stroke
What environmental factors affect the regulation of body temperature of an athlete?
Air T°
Air humidity (100% relative humidity = no sweat evaporation)
Wind velocity
Radiation from sun / ground (direct, reflected, thermal)
(Clothing)
True or false. electrolyte replacement post-exercise may not be necessary .
True, Unless a lot of Na is lost ( think sweat stains.
Is sweat hyperosmotic, iso-osmotic or hyposomotic vs. blood plasma?
Hypoismoticloss of total body water in blood. Increase concentration in plasma/ blood due to water loss.
High amount of water loos but low amounts of Na loss super concentrate na in the blood HYPER nutrimia
How does heat acclimatization occur?
What must the training factors be to induce this specific demand? (Hint %VO2max, body temperature)
Euhydration value range of urin specific gravity?
Increase blood volume*; CO; sweat gland size,’skin BF
Earlier onset sweating, and increase sweat rate
High intensity aerobic training (>70% VO2max)
High T° body (>39°C)
Euhydration value range?
<1.020 - <1.025
Urine osmolality
Euhydration ______ mOsmol/kg
Hypohydration >______ mOsmol/kg
- Ideally 700 mOsmol/kg
2. >600 mOsmol/kg
At what %BW loss would these dehydration symptoms occur?
- threshold for thirst and impairment of thermoregulation
- inc thirst, dec appetite, vague discomfort
- Dry mouth, dec urinary output, inc hemoconcentration
- dec 20-30% performance capacity
- difficulty concentrating, headache, sleepiness
- severe impairment of thermoregulation, inc respiration
- likelihood of collapsing if dehydration + heat + exercise
1% -threshold for thirst and impairment of thermoregulation
2% - inc thirst, dec appetite, vague discomfort
3% - Dry mouth, dec urinary output, inc hemoconcentration
4% - dec 20-30% performance capacity
5% - difficulty concentrating, headache, sleepiness
6% - severe impairment of thermoregulation, inc respiration
7% - likelihood of collapsing if dehydration + heat + exercise
Physiological responses to dehydration:
a. Increases in:
b. Decreases in
a. Increases in: HR Plasma osmolality and blood viscosity Blood becomes more concentrated Core T° onset sweating Core T° at which skin BF INC GI distress Muscle glycogen use
b. Decreases in: BF: Splanchnic, renal, venous BP, central blood volume SV, CO Sweat rate and skin BF at a given T°core Maximal sweat rate Performance and exercise to exhaustion
True or false. compared to Euhydrated subjects, Dehydrated subjects increase core temp and HR faster at start and throughout the exercise
True
Hypohydration & Performance. Match % decrease in perf with sport
Category of sport
a. Strength
b. Power
c. Sprint (30 sec – 2 min)
d. Endurance
Decrease in performance i. \_\_2_% ii ._3\_\_% iii._10\_\_% iv. Proportional to % loss BM; ~\_\_30\_\_% with 5% loss BM
a. i
b. ii
c. iii
d. iv
In terms periodized training, was training hypo hydrated good or bad?
Uncertain. Results were just based on one study
What are some of the health concerns for making weight?
↓plasma volume –> ↓fluid for sweat loss/thermoregulation Δ ↑risk heat injury. Due dramatic decreases in water weight.
Hyperhydration as a method for contest prerp? good or bad?
POssibly good. ↑plasma volume, ↑total body water, and (+) performance
True or false. Hyperhydration cause these effects while Training in heat: ↑ heat tolerance, ↑ duration of performance, improves performance time, ↓ HR for a given maximal aerobic workload
True. Though futher research is needed
Take home message: athletes competing in a hot climate need to increase fluid intake in days prior to event
These are risk factors for what? ( interms of electrolytes)
Excessive fluid consumption before/during, weight gain during exercise (indicating hyperhydration)
> 4 hr exercise duration
Extreme temperatures (very hot or very cold)
Low body weight
Female gender
Event inexperience
Use of NSAIDS
Hyponutremia
name 6 factors affecting fluid intake
- Thirst mechanism
- Knowledge or perception of sweat rate
- Desire to achieve pre-comp BW ( decrease)
- Palatability and tempura of fluid
- Availibility and opportunity to drink
- Avoid possibility of GI discomfort or unrination
Athletes typically finish training/competition in a a) hypohydrated or b) hyperhydrated state
a Hypohydrated
Single day endurance event: 400-800mL/hr fluids ingested –> (↓1-3% BM)
Ultra endurance event: 300-1000mL/hr fluids ingested –> (↓3-5% BM)
Teams sports: 300-800mL/hr fluids ingested (
Hydration protocol prior to exercise:
4 hr before: ___ml/kg BW (e.g. 60kg athlete: would consume)
Hot/humid? Consume an additional _____mL
5-7 ml/ kg of BW
300-420 ml
250-500ml
what are some indicators of hydration status?
Urine specific gravity
Pee test 2hr prior: dark urine? –> additional 3-5ml/kg BM
______ml of fluid, 15-20min prior to exercise, will generally be tolerated
300-400ml
Is thirst mechanism a reliable indicator of hydration status?
No, the thirst mechanism kicks in only at 2% BW loss due to dehydration.
-> Cannot plan for thirst during competition (adequate opportunities for rehydration)
is relying on the thirst mechanism, good for people with sensitive GI tracts?
NO, If long event, GI function might be compromised
1kg BW loss =___L sweat loss -> require __L fluid
1L sweat loss –> 1L of fluid
Ingestion of _____L fluid/hr is generally well tolerated, but may need more depending on _____
High sweat rate (>1.2L/hr) -> consume a _____based sport drink
0.4-0.8L
sweat loss
sodium-based
Intense exercise 60-90+min -> to sustain Blood Glucose levels, every 15-20min consume _____ml of a ___% CHO-electrolyte sport
250-500ml
6-8%
a. Composition of electrolyte replacement supplements ( recovery) CHO%, Na mmol/l, K mmol/l?
b. Fluids should be _____ and ______ to promote intake
<2% CHO, 50-60mmol/L Na+, 10-20 mmol/L K+
b. cool (10-15°C) & flavoured
true or false. Duration of rehydration may occur over several hours depending on volume required, with initial intake happening immediately post-exercise
True. High weat rate and amount would require loads of water replenishment.
Which one of these are hydration strategies and which one these are hydration factors?
i .CHO-electrolyte drink
ii. Salt loading
iii. Glycerol supplementation
iv. Milk (whey) protein
a .Temperature of fluids b. Mouth sensation c. Bolus priming (Caffeine) (Alcohol)
strats: CHO-electrolyte drink Salt loading Glycerol supplementation Milk (whey) protein
factors: Temperature of fluids Mouth sensation Bolus priming (Caffeine) (Alcohol)
How are sports drinks beneficial?
i. Prevent hyponatremia
ii. Increase palatability, thirst and drinking
iii, Limey/ citric acid taste helps to replenish water
iv. Increase rate of water intake (CHO/Na will promote water uptake in the gut)
v. Increase retention of fluid in the body
vi. Prevent hypernatremia
vii. prevent hyperhydration
i-v
Prevent hyponatremia
Increase palatability, thirst and drinking
Limey/ citric acid taste helps to replenish water
Increase rate of water intake (CHO/Na will promote water uptake in the gut)
Increase retention of fluid in the body
True or false? Large fluid w/ CHO works better than just large volume of water for increase performance.
True
true or false? CHO helps to draw in water into the system
true
True or false. CHO i) provides E substrate to working muscle and ii) (+) intestinal H20 absorption ( when [CHO] is high)
False. i) is true, however two is false. the [CHO] must be low -> If high it would be a hyper osmolar drink, drawing water into gut, slowing GE.
True or false. A CHO drink can contribute to hypohydration.
True. The % of CHO in sport drink is a ‘balancing act’ of optimizing GE rate, amount of CHO delivered and rate of intestinal absorption, while preventing net secretion of water into the intestine (i.e. [CHO] in the intestine is too high and can contribute to hypohydration)
There the %[CHO] must be low to avoid this.
Is there a ceiling effect of CHO ingestion?
yes. Beyond a certain limit, ↑CHO ingestion will NOT proportionally ↑exogenous oxidation of CHO
In fact, >10% [CHO] fluids ↑↑↑ risk GI distress
True or false. Drinks with mixtures of GLU+FRU are pointless and do not actually increase absorption of CHO as they marketed to do.
May ↑ intestinal absorption of CHO -> ↑ availability of endogenous CHO to spare muscle glycogen ->delayed onset of fatigue
Why does fructose along cause GI disturbances and not Glucose
Fructose must be absorbed via Facilitated diffusion – slower absorption
true or false. 50gFRUC+50gGLU 25-38% higher oxidation rate vs. 100gFRUC or 100gGLU
True. there appears to be a synergistic effect when combining FRUC+GLUC
true or false Evidence indicates only the addition of electrolyte Na (NaCl) and K+ are warranted
false. Evidence indicates only the addition of electrolyte Na (NaCl) is warranted
Sport drinks mmol/L of (NaCl/K+ or just NaCl) (above that, ↓palatability)
10-30 mmol/L of NaCl
True or false. Salt Loading has shown to ↑ plasma volume prior to exercise ↑ capacity to perform in warm conditions less thermoregulatory strain less perceived strain RPE
True.
What is salt loading protocol shown to enchance fluid status?
Moderate volume (10mL/kg) ~160 mmol/L over 60min, 2hr prior to exercise
Glycerol? what is it good for?
influences osmotic pressure to enhance water retention/expansion in body tissues (via reduced urinary volume)
Glycerol: effects on thermoregulation and performance?
Not yet elucidated study results
Research indicates that when glycerol dosing is______g/kgBM+ fluid ____ml/kg = net retention ~____mL water
1-1.2 g/kgBM
25-35ml/kg
600ml
true or false. Post-exercise ingestion of whey protein (either as skimmed milk or added to a CHO-electrolyte drink) may be superior to other fluids (water or sport drink) in restoring fluid balance post-exercise
True. ( Na+ content is a secondary factor)
whey protein may H20 absorption (via transport uptake)
decrease GE rate -> slower absorption H20 -> slower restoration in fluid balance -> dec urinary excretion rate
↑ osmolality of plasma –> dec. urinary excretion
Do you want increased GE during competition? What about post exercise?
During, increased: reduced GI issues
Post: Slower reduced GE, increased abortion time plus slow rises in plasma vol -> less urinary excretion
How does temp of fluid injuested effect perf?
if cold can improve perf if taen in large doses. Via decreasing core temp. ↑palatability w/ cold drinks
T or F: A mouth rinse of menthol (mint) or consumption ice-slushy beverage may improve performance.
True. Oropharangeal cold receptors are stimulated -> may improve perceptions of effort and comfort, thereby improving endurance performance
True or false. ‘mouth rinsing’ with a CHO drink during longer events (>60-90min) may also activate mouth receptors and stimulate the CNS to help maintain performance levels
True
Bolus Priming. Stimulating the stomach with a_____ before exercise -> ↑volume in stomach -> stomach ______ -> (+) GE
b. How can you avoid Gastric distress using this method? Rule of thumb for the method?
1 . fluid bolus
2. distension
b. continually ‘top up’ with fluid during exercise to maintain rate of GE
- priming fluid bolus 5mL/kg BM
