Exam #2 Flashcards
(a) What are energy requirements relativley when one is at rest (& low energy)?
(b) Nearly all ATP to sustain fucntion is via…?
(c) What is resting [blood lactate] at during rest? Provide a measurment?
(d) Why do we have blood lactate present @ rest?
(e) What is the O2 consumption at rest (healthy young person weighing 70 kg):
i. L O2/min
ii. mL O2/kg/min
iii. How much is the body’s baseline energy requirment?
(a) Constant
(b) aerobic metabolism
(c) Low and constant (1 mmol/liter)
(d) RBCs (red blood cells) have no mitochondria (only glycolysis; NADH & pyruvate → lactic acid)
(ei.) 0.25 L O2/min
(eii.) 3.5 mL O2/min
(eiii.) 3.5 mL O2/min = 1 MET
(a) How/Why does exercise present as a challenge to bioenergetic pathways/ATP synthesis?
(b) During heavy exercise, body’s total energy expenditure can be __________ times greater vs. rest
(c) During heavy exercise, utilization of ATP by working skeletal muscles can increase _ times vs. utilization at rest
(d) What does the ability to sustain exercise depend on (3)?
(a) ATP supply needs to meet ATP demand
(b) 15-25
(c) 100
(d) Fitness level of individual, exercise intensity & duration, nutrition status
Answer the following regarding this exercise-intensity category:
Moderate
(a) Exercise intensity relative to lactate threshold
(b) % Maximal HR
(c) %VO2max
(d) Subject Perception of Exercise Intensity (RPE)
(a) < Lactate threshold
(b) 50 to 75%
(c) <60% (untrained subject)
(d) Light to somewhat hard
Answer the following regarding this exercise-intensity category:
Heavy
(a) Exercise intensity relative to lactate threshold
(b) % Maximal HR
(c) %VO2max
(d) Subject Perception of Exercise Intensity (RPE)
(a) > Lactate threshold
(b) 76 to 85%
(c) 60 to 75%
(d) Hard
Answer the following regarding this exercise-intensity category:
Very heavy
(a) Exercise intensity relative to lactate threshold
(b) % Maximal HR
(c) %VO2max
(d) Subject Perception of Exercise Intensity (RPE)
(a) > Lactate threshold
(b) 86 to 100%
(c) 76 to 100%
(d) Very Hard
Answer the following regarding this exercise-intensity category:
Severe
(a) Exercise intensity relative to lactate threshold
(b) % Maximal HR
(c) %VO2max
(d) Subject Perception of Exercise Intensity (RPE)
(a) > Lactate threshold
(b) 100%
(c) > 100%
(d) All out exercise (maximal effort)
What is the formula for predicting Heart Rate (HR) max?
208– (age x 0.7)
What are the two formulas for finding %HR max?
- %HR max = exercise heart rate/HR max
- %HR max = (0.64 X % VO2 max) + 37
What is the formula for finding %VO2max?
%VO2 max = (%HR max – 37)/0.64
Distinguish which exercise intensity domains is to cause burning ( > LT) vs. one’s below LT
Cause burning/ > LT:
* Heavy
* Very heavy
* Severe
< LT:
* Moderate
(a) What is the Fick equation?
(b) What is Q?
(c) What is VO2max indicate?
(d) What is this a direct correlation of and why?
(e) What happens if VO2 ↑?
(f) What happens if VO2 ↓?
(a) Fick equation:
- VO2max = HRmax x SVmax x (A-V)O2diff max
(b) Q = HR x SV
(c) The maxmimum amt. of O2 that can be delivered & uptaken/used by the working muscles
(d) Oxygen Consumption & Aerobic ATP Production; because VO2 is an index of aerobic ATP production
(e) If VO2 ↑, then aerobic ATP prodcution ↑
(f) If VO2 ↓, then aerobic ATP production ↓
Consider the graph covered in class discussing sitting to standing:
(a) When standing, are action potentials being generated? Is
energy required?
(b) Standing to running: Any change in energy required?
Describe.
(c) How much time is necessary for Krebs/ETC to become fully
activated?
(d) What are the sources of ATP prior to Krebs/ETC become fully activated?
(e) How many minutes are required for steady-state to be
achieved?
(f) What is O2 defecit? How is it depicted in the graph? What does this mean in this scenario?
(a) Yes
(b) Yes; considerable ↑ in energy needs
(c) 2.5-3 minds. continous
(d) Stored muscle ATP, Myokinase reaction, ATP-PCr, Glycolysis
(e) About 3 mins. (around same time it takes for the end of glycolysis)
(f) O2 deficit: How much O2/ATP it would take to fulfill for exercise prior reach steady-state
- Depicted as the shaded area, prior to steady state
- Given that it takes ~3 mins. to activate, individual has to rely on other pathwyas prior
(a) How many pathways can contribute to ATP synthesis during exercise?
(b) Consider the picture from the slides, with a 100 meter swim (60 secs.), what is the percentage for aerobic vs anaerobic? What are the possible pathways used?
(a) Multiple!
(b) 30% Aerobic (KREBS/ETC); 70% Anaerobic (ATP/PCR, Fast glycolysis, Stored muscle ATP, Myokinase reaction)
(a) Recall what’s the O2 consumption at rest (mL O2/kg/min).
(b) Define steady-state VO2
(c) Explain 2 ways that an individual can respond to exercise (consider VO2max & steady state)
(a) 3.5 mL O2/kg/min
(b) Steady-state VO2: Aerobic system supply ATP
(c)
- Person 1 - Reaches VO2max at steady state & plateau occurs
- Person 2 - >VO2max (given increase in speed req. greater amt. of O2 consumption than one was able to perform), no plateau, no steady-state
(a) What is EPOC?
(b) What are the 2 components of EPOC? Which occurs first to last?
(c) What occurs in the first component?
(d) What occurs in the last component?
(a) Excess Post-Exercise Oxygen Consumption
(b) 1. Rapid component, 2. Slow component
(c) Rapid component: Steep decline in O2 use/uptake
- First few mins. following end of exercise
- O2 required to resynthesize muscle stores ATP-PCr
- Replace O2 stored in muscle cells (Mb) and blood (Hb)
(d) Slow component: Slower decline in O2 use/uptake
- Follows rapid component
- Convert lactate to glucose
- Clear blood of Epi/NoE (heart ventilatory decrease as blood circulates)
- Return body temp. to normal, resting value
(a) What/How is metabolism (ATP supply & use) respond/influenced by exercise?
(b) What patwhays are being used during short term, severe exercise ( > LT, 100% HR max, > VO2max.)
i. 2-20 secs:
ii. > 20 secs:
iii. > 45 secs:
(c) How about in a Long-term exercise (below LT) in cool environment
i. > 10 minutes:
ii. and ___ VO2 usually well-maintained, with two exceptions**
(a) Influenced by duration and intensity of exercise
(bi.) ATP-PCr
(bii.) Fast glycolysis
(biii.) Fast glycolysis & Krebs (to some degree)
(ci.) Krebs/ETC & Beta-oxidation
(cii.) Steady state
(a) What are the two exceptions to the maintanance of steady-state VO2 that was discussed in class.
(b) What is a cardiac drift?
(c) How does this change the fick equation?
(d) What causes this increase in VO2? Explain each component?
(a) 50% VO2max in hot & humid environment OR 75% VO2max in cool & dry environment
(b) Caridac drift: ↑ HR even at steady state exercise in two conditions
(c) ↑VO2 = ↑HR x SV x (A-V)O2
(d)
i. ↑ body temp. (heat accumulated) ; from energy od ATP hydrolysis
ii. ↑ [blood epi/NoE] ; ↑ fuel availiabilty → ↑ metabolic rate → ↑ HR → ↑VO2
(a) What is the incremental exercise test used for?
(b) What equipments are being used?
(c) What are the 4 metabolic responses to incremental exercise tests?
(d) Know how to explain/interpret, and describe the graph that was discussed.
(a) Used for:
1. Check for possible heart disease
2. Assess cardiovascular fitness
- Intensity increases every 1-3 minutes, until subject can’t maintain desired power output.
(b) Cycle ergometer, arm ergometer, treadmill, swim stimulator
(c)
1. VO2 ↑ linearly until VO2 max is reached.
2. VO2 max = physiological ceiling for delivery of
O2 to working muscles.
3. VO2 max influenced by
4. Not all tested will show a VO2 plateau***
(d)
- VO2peak does not verify if VO2max was hit
- VO2max (VO2 plateau) = mitochondria is full
- As workload ↑, there might be no change in VO2max = mito is full.
(a) Define the following Fick Equation variables:
i. Q max
ii. (A-V)O2 diff max
(b) What are the 4 verification of VO2max?… Identify which is the gold standard and which is the least accurate?
(ai.) Q max: Maximal ability for cardiorespiratory system to deliver O2 to working muscles (how well are the lungs working/gas diffusion)
(aii.) (A-V)O2 diff. max.: maximal ability of working muscles to uptake/utilize O2 to produce/synthezize ATP aerobically
(b) Verifications:
1. Gold standard: Achieiving a VO2 plateau; VO2 has been reached (graded ex. Test)
2. Reaching age-predicted HR max +/- 10 bpm (Least accurate)
3. Achieving [blood lactate] ≥ 8 mmol/liter (graded ex. Test)
4. Achieving RER ≥ 1.15 (graded ex. Test)
There are always exceptions!
Define Lactate Threshold (LT) vs. Onset Blood Lactate Accumulation (OBLA)
- Lactate threshold (LT): Exercise intensity that causes a non linear increase in [blood lactate]
- Onset Blood Lactate Accumulation (OBLA): Exercise intensity (%VO2 max) @ which a specific [blood lactate] is
achieved. Typically, 4 or 8 mmol/liter blood
What are the 3 possible causes of blood lactate accumulation during exercise? Explain them.
- When glycolysis is fast (exercise intensity increases), there’s an increase rate in NADH formation…
- Rate of NADH formation > Speed of NADH shuttle, NADH & Pyruvate → Lactic acid (end product of glycolysis; dissociate in to H+ & Lactate) - As exercise intensity increases, Type II fiber types will be recruited
- Isoform of LDH for this fiber type turns pyruvate → Lactate - Rate of lactate removal (or cleared).
- [blood lactate] = # lactate produced - # lactate cleared
~ ↑ = ↑ - N/C
~ ↑ = ↑ - ↓
~ ↑ = N/C - ↓
- What does VO2max represent? (3)
- What does LT represent? (5)
- VO2max represents:
* Best performance indicator in untrained populations
* Indicates maximal amount of O2 that can be consumed (ETC).
* May plateau after only a few months of training. - LT represents:
* Best performance indicator in aerobically trained populations
* Can indicate effectiveness of training program. (Tested every 3 months)
* Very trainable variable. Improvements can occur over the longer term vs.VO2 max. (Trained over the years)
* Training up to/just below the initial LT eventually moves the inflection point to the right.
* Permits training at a certain HR, when that HR is based on LT threshold testing (HR is associated)
(a) What is periodization training?
(b) What are the 3 mechanisms that affect LT (w/periodization training)? Explain each one.
(a) Periodization training: Training is broke ndown into blocks of time, within the blocks certain intensity & adaptaions will be emphasized or targeted
(b) Mechanisms that affetc LT:
1. ↑ mitochondrial density → allows for ↑ # of pyruvate to be shuttled into mitochondria → ↓ # of lactic acid produced in glycolysis. Also increases mitochondiral availiabilty for NADH shuttle
2. ↑lactate clearance due to:
a. ↑ capillary density: greater ability to move lactate out and away from working skeletal muscles.
b. Improved autoregulation (aka selective vasodilation).
↑ blood flow due to ↑ diameter of capillaries serving muscles ; ↑ blood flow to area of body that is working and vice versa
3. Improved buffering capacity due to ↑ synthesis of bicarbonate (aka HCO3-) and other buffers (more in Ch. 11)
a. Formation of CO2 from HLa
(a) What is non-metabolic CO2? Write out the formula.
(b) Where do we find metabolic CO2?
(a) Non-metabolic CO2 is the formation of CO2 from HLa from the bicarbonate buffer
HLa → Lactate
& → H+ + HCO3- (bicarbonate) ↔ H2CO3 (carbonic acid) ↔ H2O + CO2
(b) W/n Krebs
(a) Light exercise that follows intense exercise could also be described as …?
i. How does this affect lactate removal post-exercise? And how does this occur?
(b) What are the 3 ways that lactate shuttle occurs?
(a) “Active recovery”
i. [Lactate] in light exercise < [Lactate] in no exercise ; via Lactate shuttle
(b) Lactate shuttle:
1. 70% oxidized by Type I fibers in heart & within the same or nearby skeletal muscles
2. 20% → liver → glucose, via the process known as gluconeogenesis
3. 10 % → liver where it is synthesized
into various amino acids (can also produce substrates from the kreb cycle)
What is the Cori cycle? Explain the sequence of the Cori Cycle. Consider w/ exercise and when exercise ends.
Cori cycle: Converts lactate to glucose
G6P @ Skeletal muscle (glycolysis)
↓
Pyruvic acid
↓
Lactic acid (end product due to high intensity or mito. is full)
↓
Enters bloodstream
↓
Liver pulls lactic acid out of blood
↓
At liver, lactic acid become pyruvic acid
↓
G6P → Glycogen @ liver as storage
↓
Leave phosphate and eneter as glucose in bloodstream
↓
Enters skeletal muscle (-1 ATP) at G6P to continue glycolysis
Regarding the Cori cycle, a runner finished their run for that day and intake reocvery fuel (CHO)…
(a) What occurs to blood glucose levels?
(b) What hormone will then be released and how much is being released? What is this hormone repsonsible for?
(bi.) What does this mean for G6P?
(a) ↑ blood glucose levels
(b) ↑ release of insulin from pancreas (released when blood sugar is high & creating storage form of glycogen)
(bi.) G6P becomes storage in the liver and muscle (glycogen)
(a) What does RER stand for? What does it represent?
(b) What does this indicate?
(c) When is this valid? What does this assume?
(d) How is the primary substrate determined?
(e) What’s the RER value at rest?
(f) What’s the RER value when 100% fat is being used?
(g) What’s the RER value when 100% CHO is being used?
(gi.) Why are we always burning carbs?!
(a) Respiratory exchange ratio (RER): A numeric value that represents: # CO2 produced/ # O2 consumed = VCO2/ VO2
(b) Primary substrate that is utilized during exercise
(c) Valid druing rest → up to steady state (aerobic), sub max intensity exercise ; Assumes no protein is being used as fuel
(d) Nutritional status, exercise intenisty & duration, aerobic fitness level of individual
(e) 0.82 (0.71→ 0.91)
(f) 0.70
(g) 1.00
(gi.) As it’s aprecursor to oxaloacetate & malate, and needed to burn fuel (cannot burn fat w/o some carbs)
What’s the difference between the crossover concept graph vs. the switchover concept/point grapgh?
Crossover concept: (in the moment)
- x-axis: % VO2max
- y-axis: % substrate utilization
SwiTchover concept: (big picture)
- x-axis: Time (duration)
- y-axis: % substrate utilization
(a) As exercise intensity increase, there’s a gradual shift in fuel selection from….?
This is due to…
(b) A gradual shift from what fiber types? Explain the 4 points discussed/significance.
(c) As exercise intesity increases, so does what hormone concentration increases? Explain the 6 points discussed/significance.
(d) What occurs to fat as a fuel source?
(a) Fat → CHO
(b) Gradual shift from type I to type II fibers.
i. ↑ # of glycolytic enzymes
ii. ↓ # of oxidative enzymes
iii. Less mitochondrial density
iv. Epinephrine is released
(c) [Blood epi]
i. ↑ rate of glycogenolysis, which leads to
ii. ↑ glycogen phosphorylase activity, →
iii. ↑ # glucose available →
d. ↑ rate of glycolysis (fast) →
e. ↑ production of lactic acid, which is an
f. inhibitory modulator of HSL
(d) Fats as primary source of ATP is around 30 -60ish % VO2 max; As exercise intenisty increase, using farts as fuel decrease & using CHO as fuel increase.
(a) What are the 3 storage form of CHO?
(b) During exercise, when does muscle glycogen play the greatest role?
(c) During exercise, when does blood glucose play the greatest role?
(d) Where FAT is mostly stored/used?
(e) How is fat used during exercise?
(a) Blood glucose, muscle glycogen, liver glycogen
(b) At beginning of exercise or during high intensity exercise (given that its w/n the muscle cell and close to contractile proteins)
(c) During lower intensity exercise
(d) Majority of fat store subcutaneously or viscerally
(e) (Due to presense of epinephrine) TG → glycerol (→ liver → glucose) + free fatty acids (→ can be oxidized in liver (→ketones), & muscle cell (→Acetyl CoA)
(a) How much does protein contribute during exercise?
(b) What is alanine?
(bi). What are the two ways it can be used?
(c) Which amino acids are skeletal muscles able to metabolize directly?
(ci.) Under which conditions can this occur?
(a) < 1 hour: 2% ; 3-5+ hours: 5-15%
(b) Alanine: Released as a by-product of skeletal muscle contractions
(bi)
i. (Muscle - contractions - alanine) → (Blood) → (Liver - alanine → glucose) → (Blood - blood glucose) → (Muscle - G6P = start of glycolysis)
ii. Loses its amine group (NH2), forms double bond with oxygen → pyruvte (oxaloacetate & malate for Krebs to function.
- Deamination
(c) Valine, leucine, isoleucine
(ci.) Longer duration, sub-max aerobic exercise
Compare prolonged exercise at low intensity vs. high intensity to identify which os best for burning fat. Consider…
i. Energy expenditure from fat
ii. Total energy expenditure
iii. Total fat oxidation
- Low intensity (approx. 20% VO2 max)
a. High% of energy expenditure is from fat ( approx. 66%)
b. Total energy expenditure is low (approx. 3 kcals/min)
c. Total fat oxidation is also low (approx. 2 kcals/min) - Higher intensity (approx. 60 % VO2 max)
a. Lower % of energy expenditure is from fat (approx. 33 %)
b. Total energy expenditure is higher (approx. 9 kcals/min)
c. Total fat oxidation is also higher (approx. 3 kcals/min)
What is FATmax?
FATmax:
a. The exercise intensity that represents the highest rate of Fat oxidation
b. Generally, is an exercise intensity reached just before LT >
How does exercise intensity impact fat metabolism?
The higher the exercise intensity, the more HSL is inhibited.
(a) What is the normal body core temperature that humans must maintain?
(b) What occurs when body temp is > 45°C?
(c) What occurs when body temp is < 34°C?
(a) 37°C (or 98.6°F)
(b) > 45°C: Can alter enzyme structure → ↓ ability to produce ATP, which can lead to cell death or death of organism
(c) < 34°C: slows metabolism, can cause cardiac arrythmias (irregular heartbeat), which can lead to death
(a) What is meant when we say “steady-state”?
(b) What is meant when we say homeostasis?
(c) How odes the body maintain body temp w/n a relatively narrow range?
(d) During steady-state conditions, heat gain ___ heat loss.
(e) If heat gain > heat loss → net ______ in body heat.
(f) If heat gain < heat loss → net ______ in body heat.
(a) Steady-state: Variable being maintained during exercise; EX: VO2 supply & demand
(b) Homeostasis: Considers variable at rest
(c) Various systems work together to maintain body temp. w/n a relatively narrow range
(d) =
(e) gain
(f) loss
(a) What is the key function of the circulatory system?
(b) What does blood have the very high capacity to do?
(bi.) What must the body do to lose captured heat?
(c) What moves to the surface of the skin as sweat?
(a) To transport heat
(b) To capture/transport heat
(bi.) Blood flow to skin increases, which promotes loss of body heat to the environment; exposure to air will lose heat via blood plasma
(c) Blood plasma
(a) What acts as the body’s temperature control center/thermostat?
(ai.) What is its goal?
(b) Where does input come from…? What are the two areas?
(a) Preoptic-Anterior Hypothalamus (POAH)
(ai.) Maintain core temperature near 37°C (or 98.6°F)
(b) Thermoreceptors in…
1. Skin (which are first to arrive), in addition to…
2. Spinal cord and POAH itself. These signals arrive second.
(a) At rest (low demand of ATP), metabolic heat production is…
(b) What are the two ways to involuntarily produce heat? Explain each one.
(c) What are the ways to voluntarily produce heat (during exercise)?
(a) Small!
(b) Involuntary:
1. Shivering - Increases heat production 5x compared to resting values.
2. Non-shivering thermogenesis (hormones):
- From thyroid gland: Thyroxin
- From adrenal glands: Epi/NoE
- All three hormones increase rates of cellular metabolism in all cells; (At rest, rate of ATP production increase → Energy!)
(c) Voluntary:
* 70 to 80% of energy (E) expenditure is lost as heat.
* Heat produced during exercise that is not lost, is stored in body tissues → ↑ body temp
CHP. 12 SLIDE 8 NEEDS MORE INFO
What are the 3 mechanisms for losing body heat that requires a temperature gradient? Describe each one
- Radiation: Heat transfer one surface to another, but no physical contact
* Transfer of heat via: Infrared rays
* Accounts for 60% heat loss during rest
* Can be source of heat loss or gain!
* Example: The sun heats the Earth’s surface via infrared rays - Conduction
* Heat loss due to physical contact between two surfaces
* Example: After sitting on a cool metal chair for some period of time, when you stand, the surface of the chair is warm - Convection
* Heat transferred from body to air or water molecules, which are warmed and move away from heat source, and are then replaced by cooler molecules.
* Example: Sitting in front of a fan
* If air and water are same temperature, water cools 25x better compared to air. (*If water and air are same temp.)
(a) What is the mechanism for losing body heat requires a water vapor gradient?
(b) What is its mechanism?
(c) What does the rate of this mechanism depend on?
(d) When is this effective?
(a) Evaporation: when sweat gains sufficient heat, it is converted to gas (water vapor)
(b) As sweat evaporates…
i. Sweat doesn’t cool skin but, the evaporation of sweat does
ii. Evaporation accounts for 25% heat loss during rest, but,
iii. Evaporation is a KEY MEANS of HEAT LOSS DURING EXERCISE
(c) Evaporation rate depends on…
i. Air temperature & relative humidity (RH)
ii. Convective currents moving around the body
iii. Amt. of skin surface exposed to the environment
(d) Evaporation is more effective if atmospheric air is dry and not humid
(a) What is relative humidity (RH)?
(b) How is it expressed as?
(c) What is the percentge in the following?
i. High
ii. Moderate
iii. Low
(a) Relative humidity (RH): A measure of how much water vapor is in the air compared to the maximum amt. of water vapor that COULD be in the air at same temp.
(b) Expressed as percentage
(ci.) High - >60%
(cii.) Moderate - 40-60%
(ciii.) Low - <40%
(a) How does core temp. differ from other extremities in the body?
(b) How might body heat production change as you transition from rest to exercise?
(c) What effect would a change/increase in exercise intensity affect body heat production, and why?
(d) What happens if you create more body heat than you can lose?
(e) REVIEW: During moderate intensity exercise, steady state is well-maintained except in high humidity areas (↑ water vapor in air), which will affect the ability in losing heat, how?
(ei.) This will cause the body to then what? What does this mean for the cardiac ouptut?
(eii.) How does this also impct venous return?
(a) Core temp. is slightly warmer than other extremities due to body fat
(b) ↑ due to ↑ works of ATP hydrolysis
(c) ↑ due to ↑ works of ATP hydrolysis & also ↑ # of motor units recruited (Type I → Type II = ↑ body heat)
(d) Core temp. increases
(e) Hinders the ability to lose heat
(ei.) Body will sweat more ( = loss of blood plasma vol.) & body heat will ↑
- Q = ↑ HR x SV
(eii.) Decrease in venous return → blood becomes visous as well = ↑ HR & ↑ BP
(a) As exercise intensity increases, what occurs for the following…?
i. Heat production?
ii. Body temp.
iii. Core temp
iv. Increase reliance on…?
(b) As ambient air temp. increases:
i. Exercise-induced heat production
ii. What might happen to radiant heat loss?
iii. What might happen to evaporative heat loss?
(c) How does exercising in hot environment affect the ability to lose body heat? How does this affect on the following?
i. Core temp?
ii. HR (also SV)
iii. Risk of hyperthermia and injury
(a) As exercise intensity increases… (↑# motor units recruited)
i. Heat production ↑
ii. Body temperature increases linearly w/ increases in intensity
iii. Core temperature increasesdue to # active muscle muscle mass
iv. Increases reliance on evaporative heat loss
(b) As ambient air temp. increases…
i. N/C
ii. ↓ due to decrease in temp. gradient
iii. Temp. gradient ↓, ↓ in evaporative heat loss (RH)
(c) Exercise in hot environment leads to decreased ability to lose body heat.
i. ↑ in core temp.
ii. ↑ HR → ↓SV (↓venous return due to sweating)
iii. ↑ risk of hyperthermia & heat injury
What are the 3 ways that heat/humidity impact (impaired) exercise performance? Explain each one.
- CNS fatigue/dysfunciton
- Decreaesed motivation/degraded cogntive function
- Reduced voluntary activation of motor units (self-preservation) - Cardiovascular dysfunction
- Reduced stroke volume: due to ↑ blood flow to skin → ↓ SV
- Decreaesed cardiac output during high intensity exercise,…
- Decreased muscle blood flow…
→ ↓ # of O2 & nutrients to muscles
→↓ # of CO2 & lactate clearance
→ ↓ # blood flow to liver → ↓ # glucose prod. via gluconeogenesis - Accelerated muscle fatigue
- Increased radical production: Free radicals (released from muscle contraction) can bind to actin/myosin, causing damage
→ ↓ # of x-bridges formed →… fatigue
- Decreased muscle pH: slow enzyme activity rates → slowing speed of contraction → fatigue
- Muscle glycogen depletion:
~ Intenisty ↑ → ↑ glycogen phosphorylase activity → ↑ rates of G6P synthesis → ↑ rates of glycolysis → ↑# end product of fast glycolysis (lactic acid) → SLOWS ENZYME ACTIVITY
(a) What’s the priamary stimulus for adaptations to heat exposure?
(b) How many days does it take for one to become aclimmated with heat?
(c) What are the 5 adaptations to heat exposure?
How long does it take for the following adaptions to take place when one has days of continuuos exposure to heat?
(a) Decrease in HR
(b) Plasma volume expansio
(c) Percieved exertion decrease
(d) Sweat rate
(a) Heat tolerance decrease significantly within ___ days after withdrawal from heat exposure
(b) Complete loss of heat acclimation after ___ consecutive days away from heat exposure. Why does this occur?
(a) What detects cold stress in the body? (Consider the order!)
(ai.) How does this help maintain the body’s set-point temp.?
(b) Draw out a diagram on the physiological responses to cold stress.
(a) Define cold stress
(b) Define hypothermia
(c) Greater ability to withstand cold stresses? Very lean vs. not as lean ? Why?
(d) Typically, do men or women have greater % body fat?
(a) At rest, and with exposure to cold,what happens to blood flow to the skin?
(b) How is wearing shorts and tank top different from wearing a sweater and long pants when exposed to cold?
(c) What happens to temperature gradient when exercising in a warm environment vs. a cold environment?
What are the 3 factors that affect body heat loss? Expplain each one.
Explain the 3 ways disscussed in class how cold stress effects exercise perfomance:
(a) Hands exposed to cold can become numb due to: (blood flow & neural transmission)
(b) Exercise on cold air
(c) Exercise in cold water
With chronic exposure to cold temperature…
(a) Shivering begins at ____ skin temp. vs. non-acclimated persons
(ai.) Cold acclimated persons rely more on _____________ vs. shivering to maintain body temp homeostasis
(b) Cold acclimated persons maintain higher mean ______________due to improved, intermittent peripheral vasodilation
(c) Cold acclimated persons have ____________ to sleep in cold temperatures without _________________.
(d) Cold acclimation is evident after _______ of exposure to cold.
What are some of the potential health risks with cold exposure in the follwoing scenario:
(a) Prolonged cold-water immersion
(b) Cold air exposure
