Post-Midterm Content Flashcards
What is dehydration? What can cause it to happen faster?
decrease in body fluid from normally hydrated state
cause increased physiological strain and RPE, impaired performance
exercise in heat can cause this to occur faster due to increased sweating
What are the symptoms of dehydration?
thirst fatigue weakness dizziness irritability reduced mental alertness impaired vision and muscle control
What % of body mass is water? What % of muscle?
50-70% of body mass
- slightly more in males
75% of muscle mass
- leaner = more water
What are the water intake recommendations for men and women? From what sources?
women = 2.2 L
- more if pregnant
men = 3 L
20% from food, 80% from fluid/beverage
What is the purpose of sweating? What is average sweat rate?
principal means of preventing rise in body temperature
loss of body water and electrolytes
1 L/h
Give some examples of how the following systems are affected by hydration:
CNS
muscle
cardiovascular
psychological
CNS
- temperature, brain metabolism
muscle
- temperature, metabolism
cardiovascular
- blood pressure, oxygen delivery
psychological
- RPE, thermal comfort
How does the cold affect your hydrating habits?
decreased urge to drink
decreased intake due to not wanting to remove clothing to pee
Describe your core temperature in the following situations:
- acclimated, euhydrated
- unacclimated, euhydrated
- unacclimated, dehydrated
- temperature plateaus normally while hydrated
- ex. exercising in Cuba, not used to heat so core temperature rises higher but still safe due to hydration
- dangerous
- HR increased due to decreases BV
What are the 3 ways we can lose fluids?
respiration
skin
feces/urine
What are the 3 ways we can gain fluids?
drinking
eating
metabolic (water created through chemical processes)
What are the adverse effects of sweating at different levels?
can decrease performance at as little as 2% of body weight
can collapse at 7% or greater
10-15% loss = spastic muscles, decreased vision, painful and decreased urination
For every L of O2 consumed during exercise, how many kcal are burned?
5 kcal
4 heat, 1 work
How do we determine heat production?
VO2 (L/min) x 5kcal/L
kcal/min x 0.80 (efficiency - lose 80% as heat)
x 60 mins/hr
What is the specific heat of skeletal muscle?
0.83 kcal/kg/C
How do you determine how many kcal it would take to raise the body temperature by 1 degree C?
specific heat (0.83 kcal/kg/C) x kg
How do you determine how much a person’s body temperature increases?
C = kcal heat produced/(specific heat x kg)
What are the different methods of dissipating heat?
evaporation (major)
- sweat loss
- respiratory
convection
- physical contact (ex. running in cold air)
radiation
- no physical contact (ex. sunlight gain)
How many kcal does 1L of sweat rmove?
600 kcal
Describe the input, sensors, integrator, and effectors of body heat loss
input
- exercising muscles and environmental heat gain = heat load
sensors
- core or skin
integrator
- hypothalamus
- modifying inputs: BP, osmolarity, hormones
effectors
- cutaneous vasodilation
- sweating
What are the functions of water?
building material for cell protoplasm
protects vital body areas (non-compressible)
controls fluid/electrolyte balance
- via changes in osmotic pressure
main component of blood
regulate sensory organs and body temperature
What are the compartments of water? How does travel between them work?
65% intracellular, 35% extracellular
can move freely among compartments via semipermeable membranes
direction controlled by solute concentration gradients
What is osmolality? What are the units?
aka tonicity
measure of solutes in solution
1 osmol = 1 molecule of any non-ionic substance
1 mmol = 1 mosmol
1 mmol of a substance that can dissociate into 2 ions = 2 mosmol (ex. NaCl)
hypertonic = greater hypotonic = lower isotonic = same
What happens to osmolality if you drink a highly concentrated sports drink?
may pull solution the wrong way
draw water into GI tract from blood, resulting in decreased water absorption
What are osmoreceptors?
in hypothalamus
monitor osmotic pressure
release ADH from pituitary to tell kidneys to reabsorb fluid to conserve water
- alcohol prevents ADH release = dehydration = hangover
What does hypertonicity have to do with dehydration?
blood becomes hypertonic in dehydration and water from cells enter the blood to maintain blood volume
due to excess sweating or inadequate drinking
What are electrolytes?
charged particles in solution conducting an electric current
control metabolic reactions by activating enzymes
What % of weight loss from exercise is sweat?
90-95%
What are the effects of sweat loss through exercise?
increased plasma volume and blood flow to skin for cooling
decrease central blood volume
- water comes from the blood
- causes series of events (ex. increased HR, decreased SV/Q)
- leads to decreased exercise performance
What are the contents of sweat?
vast majority water
highest concentration of electrolytes in plasma = highest concentration lost in sweat
- Na, Cl, K are most
What do we need to replace after exercise?
fluid
- cool body temp and replace fluid losses
CHO
- fuel
Na+
- when sweat losses and water intake are high
- hyponatremia = low blood sodium due to dilution
What is the difference between GES and GPS?
glucose electrolyte solution = high fluid low CHO
- ex. sports drink
- use when fluid and CHO both important
glucose polymer solution = high CHO, low fluid
- use when CHO more important
- 10-20% concentration
What are drinking recommendations?
increase fluid volumes in training
cool temperature fluids make you drink more
drink early and often
avoid diuretics
sports drinks only better when fluid and sugars are compromised by exercise
How do you calculate sweat rate?
absolute
(pre-exercise weight - post-exercise weight) x L
= L x 0.95 (95% weight loss is sweat)
= L
relative (time)
absolute L/time mins x 60 mins/1 hr
= L/hr
How do you calculate body mass loss?
absolute sweat loss in kg/pre-exercise weight x 100%
How do you calculate performance change?
[(time 1 - time 2)/time 1] x 100%
What is hyponatremia?
normal Na+ level is diluted due to excess water intake
nausea, fatigue, confusion, seizures
represents inverted-U hypothesis
How much glycogen does the muscle regularly store?
300-400g
largest store
How much glycogen does the liver store?
80-110g
primary site of gluconeogenesis - can increase stores
liver contributes more as intensity increases
What is hypoglycemia?
blood glucose below 3 mmol/L
rate of glucose delivery to brain is insufficient to meet dietary requirements
dizzy, nauseous, cold sweats, increase HR, hunger, etc.
Study: completed 3x 16km runs over 2 days, one group with low CHO and other with high CHO. What happened to their performance?
low CHO group didn’t replenish stores between runs
performance gradually decreased
What is the general CHO intake recommendation? What about training specific recommendations?
5-13g/kg depending on intensity and duration
minimum 130g/day (bogus)
moderate training = 5-7g/kg
intense training = 8-13 g/kg
What are recommendations for CHO intake after exercise?
high GI and nutrient rich CHO in recovery
in combination with PRO
if less than 8 hours between exercise, CHO intake immediately
What is the classic super-compensation protocol?
period of CHO deprivation after exhausting exercise increases glycogen resynthesis
exercise 1 then deprivation then exercise 2 to completely drain CHO from muscles
then taper exercise and CHO load leading up to competition
What are disadvantages to classic super-compensation protocol?
hypoglycaemia during low CHO = poor recovery
GI distress
injury risk
mood disturbances
What is the moderate super-compensation protocol?
normal training taper with moderate-high CHO intake
as effective and less demanding/problematic
gradually taper training leading up to compensation while gradually increasing CHO intake
How long does CHO loading take? Is it necessary? How much?
most athletes will require supplementation to ingest sufficient CHO
at least 5g/kg, 8-10 for maximal glycogen levels
- should be a mixture of high and low GI
takes several days to increase muscle glycogen stores
What are the effects of CHO loading?
increase TTE
increase time trial performance
need to be at least 90 mins for benefits
- makes sense - glycogen not performance limiting below this
- also saw benefits in hockey (repeat intense bouts)
increase body weight about 1kg
- gain 3g H2O for every 1g of CHO
What kind of pre-exercise CHO intake should occur? (3-5hrs) What are the effects
if not going to load, at least need adequate CHO
2-4g/kg, 3-5 hours prior
- prevent transient decrease in blood glucose with exercise onset
- increase oxidation of CHO
- blunt FA mobilization/oxidation
Should you intake CHO 30-60 mins before exercise?
not the best strategy
causes large increase in plasma glucose and insulin, still see rapid decrease in blood glucose with initiation of exercise
- rebound hyperglycemia
What are the views on CHO intake during exercise?
beneficial for exercise over 45 mins
- our primary fuel source during high intensity but we have limited stores
maintains blood glucose
promote glycogen synthesis
positively affect motor skills and CNS
What is CHO mouth rinsing? What are its effects?
swish CHO formula in mouth and then spit it out
brain senses changes in composition of contents in the mouth and stomach
may sense CHO via receptors in the mouth and promote enhanced well-being
mixture of glucose and fructose
What is the plateau for CHO oxidation?
0.8-1.0 g/min
even if intake is hire
Does timing of CHO intake matter?
not necessarily (bolus vs small repeated)
just important to consume
Does amount of CHO intake matter?
optimal = amount that results in highest CHO oxidation
no point in intaking more than you can use
again, peak is around 1.0g/min
Does type of CHO ingested matter?
glucose is best
- fructose and galactose have lower oxidation rates
disaccharides have similar oxidation rates but need much more time for ingestion
solid foods take longer to absorb
increased oxidation when combining glucose and fructose
What happens as exercise intensity increases?
muscles rely more on CHO
exogenous CHO rates peak at 60% VO2
What is oxidation efficiency?
% of ingested CHO that is oxidized
% of what is taken in that is used
What is the purpose of post-exercise CHO intake?
replenish depleted glycogen stores in liver and muscle
What determines the rate of glycogen synthesis?
availability of glucose
transport of glucose to muscle/liver
activity of enzymes
What are the 2 phases of glycogen sythesis?
fast and slow
- additive
fast = CHO ingested immediately post-exercise
- muscle contraction effects
- glycogen synthase
- abundant GLUT4
- critical window of 2 hours
slow = CHO ingested 2h after exercise
- glycogen synthesis still occurs just at slower rate
- insulin effects
if you eat right away, get insulin effect and muscle contraction effect
- if you wait too long, only get insulin effect
How does pairing PRO and CHO intake after exercise alter benefits?
max out by providing enough energy - not necessarily benefits to adding PRO
though protein increases insulin response, may result in highest glycogen re-synthesis
why chocolate milk works
Is there a difference between solid and liquid CHO intake?
rates likely similar but solid may have more CHO
if you need large amounts wont be able to drink it all
When is fat the best fuel?
low-moderate intensities
Where is fat stored?
most in subcutaneous adipose tissue
some in muscle as IMTGs
What is lipolysis?
fats stored as TGs, must be mobilized and transported by lipases
activated by catecholamines
Describe fat processing activity at rest.
overactive
70% of FA are re-esterified (built back up)
Describe fat processing activity during exercise.
re-esterification is suppressed - more is available for use
increased lipolysis
Where do most FA bind?
albumin (99%)
What is plasma FA concentration at rest? What happens with exercise?
0.2-0.4mmol/L
prolonged exercise can increase this to 2mmol/L
- higher can be toxic, body processes it into VLDL
Which muscle fibers have the most IMTGs?
type 1
usually located close to mitochondria
How are FAs brought into mitochondria?
activated by acetyl-CoA synthase
bound to carnitine
transport across outer membrane by CPTI
transport across inner membrane by CPTII
What happens to fat use as exercise increases in intensity?
sleeping = entirely fat oxidation
when exercise starts, lipolysis increases, esterification decreases
moderate intensity = lipolysis increases, esterification decreases, blood flow to adipose tissue increases
increases as duration increases, peaks around 65% VO2
What is the limitation to FA use?
getting FA into the mitochondria
What kind of training adaptations occur to fat oxidation?
increased # and density of mitochondria
increased capillary density
increased FA transporters
How does diet affect fat oxidation?
more fat = more fat use
not last meal effects, more chronic
- can see affects as soon as 5 days
CHO feeding increases insulin which decreases lipolysis
- fat use mainly influenced by rate of CHO oxidation
Should we take LCTG during exercise?
no
- take long time to reach circulation
- potent inhibitors of gastric emptying
- not oxidized well
only TGs used for energy provision in exercise
Should we take MCTG during exercise?
probably not beneficial
do get absorbed into blood faster, but oxidized in the liver not as fuel (don’t get to muscle)
Is fat loading beneficial?
having more fat may be beneficial but most important thing is enough CHO
What are ketone bodies?
byproducts of fat metabolism
produced for energy when CHO intake low
Is fasted training beneficial?
no
decrease in performance at competitive intensities
Is there benefits to high fat diets?
no
impairs CHO use which is most important
only benefits below competitive intensity
does increase fat utilization/CHO sparing
What is linoleic acid?
omega 6 FA
2 double bonds
in oils, veggies, processed foods
easily obtained
What is alpha linoleic acid?
omega 3 FA
3 double bonds
significant health benefits
in deep ocean fish, some oils
How have omega 6:3 ratios changed? Why?
used to be 1:1 when we ate paleo
now like 30:1
due to changing food habits
- decreased fish, increased corn-based product in effort to avoid butter/shortening
may be significant factor to many diseases of Western society
What oils have the best ratios?
canola is best of affordable options
flax seed oil is actually best
What are some omega-3 rich foods?
cold water fish
oils
green leafy veggies
free range animals and their products
What are some omega-6 rich foods?
oils
corn/grain fed animals and their products
Do omega-3 and omega-6 get along?
no
they compete for spots in cell membranes
What are eicosanoids? How do they change depending on what fats they’re made of?
hormone like chemicals formed from phospholipids
thromboxanes, prostaglandins, leukotrienes
omega 6 eicosanoids increase blood viscosity and vasoconstriction (bad)
omega 3 eicosanoids are the opposite
What are the health benefits of omega 3?
reduce many risks of CV disease and heart attack
help with cancer treatment and prevention
help with T2D
prevent obesity
increases fat utilization
What are peroxisomes?
similar to mitochondria but less effective
activity increased by omega 3
increases fat usage with less energy produced
- weight loss
What are uncoupling proteins?
allow alternate route for protons to re-enter the matrix
uncouples fuel oxidation and ATP production
metabolically active fat
Does omega 3 FA have ergogenic effects?
decrease in body fat a benefit for most sports
burn more fat during exercise
What is the role of PRO?
maintain optimal metabolic functioning
form skeletal muscle and lean mass
immune function
What are the PRO requirementes?
endurance/team sport athletes: 1.2-1.4g/kg
strength athletes: 1.6-1.8g/kg
general requirement for adults is 0.8g/kg
What is the master regulator of PRO synthesis?
mTOR
Does CHO help PRO synthesis?
yes
CHO helps support uptake of AA
increased synthesis when insulin released
decrease breakdown
fat sustains AA supply to increase MPS
How does PRO intake timing affect effects?
20g seems to be ideal dose (intermediate)
fraction synthetic rate highest
(20 x 4 > 10 x 8/40 x 2)
1-3 hour window that PRO ingestion is optimal
- shrinks as you age
Can you get too much PRO?
yes
just wasteful, oxidized if intake is in excess
- muscle full effect
optimal dose 0.4g/kg/meal
When is MPS highest?
in combination of eating and exercise
additive effects
Does pre-exercise intake have benefits?
increased AA availability may increase MPS
eating early and enough = good
IS there harm to too much PRO?
may cause additional kidney stress
increased dehydration risk
increased fat deposition
What is PEM?
protein energy malnutrition
long-term inadequate PRO or energy intake (or both)
wasting body tissues, more susceptibility to infection
What is sports anemia?
high intensity training, low PRO intake
reduced blood Hgb concentration (appearance of anemia)
Does type of PRO matter?
intact takes longer to digest than AA but both beneficial
complete greater than incomplete
liquid gets in faster
What is biological value?
finds how much pro you ate that was useable
if complete PRO retained = absorbed, BV = 100%
if incomplete, retained < absorbed, BV = 100%>
What are other PRO efficiency measures?
PRO digestibility
- quality of PRO based on AA requirements of child
- based on AA profile, content, digestibility
PRO efficiency ratio
- weight gain/PRO intake
AA score
- amount of limiting AA in food compared to reference food (egg PRO)
Indicator AA oxidation
- all others oxidized, so intake of limiting AA increased, intake of other AA decreases
What is the difference between whey and casein?
whey = rapid MPS (high GI)
- cheese
casein = slow/prolonged MPS
- milk
- may be better chronically
What is the role of leucine?
key BCAA in stimulating mTOR for protein synthesis
10g/100g whey
What are ways to measure PRO use? (that we actually use)
AV difference
- AA concentration on either side of a tissue
- indicates net exchange
Tracer
- label AA with isotope
Indicator
- ingest labelled AA and measure oxidation
- once enough ingested, oxidation decreases
What are the 4 R’s of the post-exercise period?
rehydrate
refuel
repair
remodel
Anderostenedione?
popular
increase testosterone (MPS, muscle mass, recovery)
bad
Arginine?
increase NO which will increase O2 and fuel substrates to muscle
bad
Arginine paradox = saturated with normal levels
Beta Alanine?
increase muscle carnosine to increase muscle buffering (less lactic acid, exercise longer)
good
HMB?
decrease MPB, increase MPS
makes leucine
bad
BCAA?
supplementation increase body stores
good during aerobic exercise
- increase TTE, decrease MPB
sideways
Caffeine?
stimulates CNS to make exercise feel easier
Carnitine?
involved in FFA transport across mitochondria
supply will increase muscular stores, increase FFA transport to increase oxidation
CLA?
omega 6 FA
minimizes muscle catabolism
- increase lean mass and RMR
too little prevents use of fat as energy
What are the creatine loading protocols?
rapid
- 20g/d (4x5) over 6 days
prolonged
- 3g/d over 28 days
both work
Energy drinks?
increased CHO (energy), prolong exercise intensity, stimulant (caffeine)
stimulate CNS
bad
only effects caffeine
Ephedrine?
increased fat metabolism and RMR
suppress appetite
increase EE
bad
Glutamine?
prevent MPB by providing AA to spare muscle stores
bad
Glycerol?
energy during exercise
bad
Green tea?
provide energy, increase fat oxidation
bad
Ketone salts?
used as substrate in muscle
bad
MCTs?
faster absorption
spare muscle glycogen, prolong exercise intensity
bad
Dietary nitrates?
increase NO, vasodilate
- improved tolerance to high intensity exercise, delivery of O2/fuel substrates
increase performance
sideways
Does training with low muscle glycogen have advantages?
maybe metabolically, still too early to prescribe
increases muscle glycogen, metabolic enzyme activity
probably decreases efficiency due to reduced energy
What is the difference between overtraining and overreaching?
overtraining = accumulation of stress resulting in long term performance decreases
- weeks to months recovery
overreaching = accumulation of stress resulting in short term performance decreases
- days to weeks recovery
often no symptoms other than decrease performance
What are vitamins? How are they named?
organic compounds required for biochemical functions that can’t be synthesized by the body
named in order of discovery (A was first)
Why were English sailors called limeys?
when they went out to sea had many issues related to vitamin C deficiency, when they started bringing more limes they got better
What are the functions of vitamins?
energy metabolism
oxygen transport
building blocks of body tissues
antioxidants
How do antioxidants prevent free radical damage?
from incomplete oxidation, unpaired electrons unstable and dangerous
take electrons from stable molecules and make more free radicals
antioxidants donate electrons to free radicals to stabilize them without becoming one themselves
What is the universal benefit of supplementation?
deficiencies will adversely affect performance
increased intake results in little benefit
if we eat enough and have a well-balanced diet, little need to supplement
What are minerals?
inorganic elements that function as building blocks and regulators
When would marginal nutrition be a higher risk?
low body weight sports
competition weight sports
low fat sports
training in heat sports
eat enough and a well-balanced diet!!
