22-24) *** Adaptations to Aerobic Training *** Flashcards
How do adaptations to training differ between Aerobic and Anaerobic Training?
Aerobic training:
- “Cardiorespiratory endurance training”
- Improves cardiac fxn and peripheral blood flow
- enhances metabolic capacity of mm fibers (mm generate more ATP)
Anaerobic training Improves:
- anaerobic metabolism
- Short-term, high intensity (explosive) exercise capacity
- Tolerance for acid-base imbalances
- Muscle Strength
Greatest athletic success comes from training both systems
Muscular Endurance vs Cardiorespiratory Endurance:
Define.
Which are improved with aerobic training?
Aerobic Training improves both!
Muscular Endurance: Ability of a single muscle or mm group to maintain high-intensity, repetitive or static contractions
- Highly related to Muscular strength and Anaerobic power development
Cardiorespiratory Endurance: Ability to sustain prolonged, dynamic whole-body exericise using large mm groups
- related to development of CV and Resp systems’ ability to use energy aerobically
- Ability to maintain O2 delivery to working mm during prolonged exercise and
- mm ability to use energy aerobically
Anaerobic power development: ATP produced anaerobically, trained aerobically
Cardiorespiratory Endurance Capacity
What is Maximal Endurance Capacity?
How does it change with Exercise?
Maximal Endurance Capacity: VO2max
- Highest rate of oxygen consumption attainable during maximal or exhaustive exercise
- Maximal Aerobic Power or Maximal Aerobic Capacity
- ↑Excerise intensity → o2 consumption will plateau or decrease slightly even w/ increases in workload
Endurance Training:
- Increases maximal endurance capacity: more O2 can be delivered to and used by active mm than in untrained state
- ↑VO2max
- ↑ capacity for intense exercise
Cardiorespiratory Endurance Capacity
How does Maximal Endurance Capacity change with endurance training?
Endurance Training:
- Increases maximal endurance capacity: more O2 can be delivered to and used by active mm than in untrained state
- ↑ VO2max
- ↑ capacity for intense exercise
Maximal Endurance Capacity: VO2max
- Highest rate of oxygen consumption attainable during maximal or exhaustive exercise
- Maximal Aerobic Power or Maximal Aerobic Capacity
- ↑Excerise intensity → o2 consumption will plateau or decrease slightly even w/ increases in workload
What is Submaximal Endurance Capacity? How does it change with Endurance training?
Submaximal Endurance Capacity:
- Ability to maintain peak speed or velocity during a set period of time
- Likely determined by both V̇O2max and Lactate threshold
Submaximal Endurance Capacity increases with training
ie the distance one can run in 30 minutes increases w/ training
Repeated challenges to cardiovascular/respiratory systems leads to ? to allow body to improve ?
Repeated challenges to cardiovascular/respiratory systems leads to adaptations to allow body to improve VO2max
- Goal: to improve VO2max and how long you can exercise near VO2max
Multiple CV adaptations occur in response to exercise training:
1. Heart rate
2. Stroke Volume
3. Blood Pressure
4. Cardiac output
5. Blood flow
6. The blood
What are 6 CV factors that adapt in response to training?
Multiple CV adaptations occur in response to exercise training:
1. Heart rate
2. Stroke Volume
3. Blood Pressure
4. Cardiac output
5. Blood flow
6. The blood
What is the (a-ṽ)O2difference
Does it respond to training?
Refers to oxygen transport system:
* (a-ṽ)O2difference: Arterial-venous O2 Difference
* Difference between arterial and venous O2
* Reflects amount of O2 extracted by the tissue
* As extraction of O2 ↑ (rate of O2 use ↑) → ↓ amount of O2 in venous blood → ↑ (a-v)O difference
- Endurance training causes numerous changes in the oxygen transport system to allow it to function more effectively
Changing HR or SV changes CO which impacts V˙O2max
V˙O2max = highest rate of oxygen consumption obtainable during maximal or exhaustive exercise
~max
* V˙O2max = CO x (a-v)O2difference = rate of oxygen consumption
* CO = HR x SV
V˙O2max Equation?
- What is V˙O2max
- How does it relate to the oxygen transport system?
V˙O2max: highest rate of oxygen consumption obtainable during maximal or exhaustive exercise
* V˙O2max = CO x (a-v)O2difference = rate of oxygen consumption
* CO = HR x SV
Endurance training → numerous changes in the oxygen transport system to allow it to function more effectively
* Changing HR or SV changes CO which impacts V˙O2max
- (a-ṽ)O2difference: Arterial-venous O2 Difference
- Difference between arterial and venous O2
- Reflects amount of O2 extracted by the tissue
- As extraction of O2 ↑ (rate of O2 use ↑) → ↓ amount of O2 in venous blood → ↑ (a-v)O difference
Heart size
* Cardiac hypertrophy or ?
* ?-induced; normal adaptation to training
* ? undergoes greatest adaptation
* Type of ? depends on type of exercise performed
Heart size
* Cardiac hypertrophy or athlete’s heart
* Training-induced; normal adaptation to training
* Left ventricle undergoes greatest adaptation
* Type of ventricular adaptation depends on type of exercise performed
Ventricular Adaptation to:
(1) Strength-based (static) training
* Concentric LV hypertrophy
* Due to pressure load
* LV wall thickening and minimal LV dilation
(2) Endurance-based training
* Eccentric LV hypertrophy
* Due to increases in volume load
* LV dilation and proportional LV wall thickening
* Increased plasma volume and diastolic filling time
* leads to LV dilation:
* Allows for increased left ventricular filling and increased SV
* Largely attributable to a training-induced increase in plasma volume that increases left ventricular EDV
* Decreased heart rate at rest due to increased parasympathetic tone, and during exercise at the same rate of work, increasing diastolic filling
Ventricular adaptation to Strength-Based (STATIC) training:
(vs Endurance)
Ventricular Adaptation to:
Strength-based (static) training
* Concentric LV hypertrophy (reduced ventricular volume)
* Due to pressure load
* LV wall thickening and minimal LV dilation
(2) Endurance-based training
* Eccentric LV hypertrophy
* Due to increases in volume load
* LV dilation and proportional LV wall thickening
* Increased plasma volume and diastolic filling time
* leads to LV dilation:
* Allows for increased left ventricular filling and increased SV
* Largely attributable to a training-induced increase in plasma volume that increases left ventricular EDV
* Decreased heart rate at rest due to increased parasympathetic tone, and during exercise at the same rate of work, increasing diastolic filling
Heart size
* Cardiac hypertrophy or athlete’s heart
* Training-induced; normal adaptation to training
* Left ventricle undergoes greatest adaptation
* Type of ventricular adaptation depends on type of exercise performed
Ventricular adaptation to Endurance Training
(vs Static/Strength)
Endurance-based training
* Eccentric LV hypertrophy
* Due to increases in volume load
* LV dilation and proportional LV wall thickening
Increased plasma volume and diastolic filling time
* leads to LV dilation (to account for extra Vol):
* Allows for increased left ventricular filling and increased SV
* Largely attributable to a training-induced increase in plasma volume that increases left ventricular EDV
* Frank starling: ↑EDV→ ↑SV
* Decreased heart rate at rest due to increased parasympathetic tone, and during exercise at the same rate of work, increasing diastolic filling
Ventricular Adaptation to:
Strength-based (static) training
* Concentric LV hypertrophy (reduced ventricular volume)
* Due to pressure load
* LV wall thickening and minimal LV dilation
Heart size
* Cardiac hypertrophy or athlete’s heart
* Training-induced; normal adaptation to training
* Left ventricle undergoes greatest adaptation
* Type of ventricular adaptation depends on type of exercise performed
Heart Size & VO2max:
* Highly trained endurance athletes have greater ? than non-endurance training athletes
LVID and LVM increase with endurance training
Heart size
* Highly trained endurance athletes have greater left ventricular masses than non-endurance training athletes
* Left ventricular mass highly correlated with VO2max (VO2max dependent on CO which depends on SV)
(cross-country skiers, endurance cyclists, long-distance runners)
Graph: literature review: LVID (left ventricular internal diameter; index of chamber size), MVT (mean wall thickness), LVM (left ventricular mass)
* LVID and LVM increase with endurance training
* Longitudinal studies show increases with heart size with training and decreases with detraining
CV adaptations to training: Stroke Volume
Stroke Volume increases following Endurance Training, why?
Stroke volume:
Increases at rest and with submaximal/maximal exercise intensity following endurance training
(1)Left ventricle fills more completely during diastole after aerobic training (increased EDV)
* ↑Plasma volume w training → ↑EDV → ↑Dilation → ↑SV
(2)Heart rate of trained heart is lower at rest and during the same exercise intensity than untrained heart, ↓HR →↑diastolic filling
* Increased stretch of ventricles and force of contraction increases SV (Frank-Starling mechanism)
SV plateaus at about 40-60% VO2max
What is the Ejection Fraction (EF)? Why does EF increase after aerobic training?
Ejection fraction: proportion of the end-diastolic volume (EDV) that is pumped out with each beat
EF = (EDV - ESV)/EDV
Aerobic Training:
- LV fills more completely during diastole → ↑EDV
- ↑LV wall MASS →↑contractile force and ↓ESV (push out more blood)
facilitated by decreased peripheral resistance with training
* More blood enters the left ventricle and a greater % of what enters is forced out with each contraction, resulting in increased SV
Stroke volume is the amount of blood the heart pumps with each beat. SV = EDV-ESV.
CV Adaptations to training HR
HR: How does aerobic training lead to HR changes at rest? During submaximal exercise? During Recovery?
Heart Rate adaptions to Aerobic Training
- Major impact at rest, during submax exercise & recovery period
- Resting HR ↓ w/ Endurance Training
Training-Induced Bradycardia (very slow HR)
Resting Bradycardia in athletes:
Three possible explanations
Training-induced Bradycardia: Low resting HR in elite athletes
(1) Due to ↑ Parasympathetic (Vagal) Tone → ↓HR
(2) ↓ Sympathetic Tone
(3) ↓Intrinsic HR (set by SA node in absence of neural/hormonal input)
- Remodelling of SAN
- Changes properties of ion channels and Ca++ handling
- Causes bradycardias associated with SAN disease
How does aerobic training alter submaximal HR?
During Submaximal training, aerobic training →↓HR at any given intensity
- Larger decreases seen at higher intensities
Trained Heart performs less work (lower HR and Higher SV) to maintain CO at a specific intensity
Aerobic training and HRmax:
Does aerobic training alter maximum heart rate?
Maximum heart rate (HRmax):
* Stable and remains relatively unchanged
after endurance training
* Determined by age
* Exception: highly trained endurance athletes may have lower HRmax values than untrained people at same age
At maximal or near-maximal exercise intensities, ? and ? provide optimal CO
At maximal or near-maximal exercise intensities, HR and SV provide optimal CO
CO=HR x SV
- If HR is too fast → ↓diastolic filling time → ↓SV
- Highly trained athletes may have lower HRmax as hearts have adapted to training by Increasing SV so lower HRmax can provide optimal CO
What is Heart Rate Recovery?
How does it change with Endurance Training?
Heart Rate Recovery (HRR): Measure of Cardiorespiratory Fitness
- HR remains elevated after exercise, slowly returning to resting level
- HR Recovery period = period of time it takes to return to resting HR
After Endurance training:
- HR returns to resting more quickly after exercise in both maximal and submaximal exercise (Faster recovery)
Cannot compare HRR between individuals but can use it to track personal progress
B/c other factors affects HRR (Core body temp)
How does Cardiac Output change with Aerobic Training?
- At rest?
- Submaximal Exercise
- Maximal Exercise
CO = HR x SV
Rest and during submaximal exercise:
- Little change in CO; matches VO2
Max CO may increase in response to aerobic training:
- Largely responsible for increased VO2max
- Increased due to increase in SVmax as HRmax changes very little
CO = HR x SV
- SV increases with Training
- HR decreases with training at rest and during exercise
Fick eq’n CO affects O2 delivery
Bloodflow: What are 4 factors that increase BF in response to exercise?
(1) ↑ Capillarization
- ↑ # of capillaries per mm fiber
(2) Greater recruitment of existing capillaries
- Not all capillaries in a tissue are open at one time
- ↑BF to working mm
(3) More effective BF redistribution from inactive regions
- Redistribution of CO; ↑BF to active tissues
(4) ↑ Total Blood Flow
BV increases due to increased plasma volume and volume of RBCs
Why is increasing RBC volume a benefit?
Volume of red blood cells
* Increases with endurance training
* Increased oxygen-carrying capacity
Hematocrit may decrease (%RBC)
* Hematocrit = red blood cell volume/ total
blood volume
* Trained athlete’s hematocrit can decrease so athlete appears anemic
Increased plasma volume increases more than RBC volume
* Decreases viscosity (prevents thickening of blood)
Plasma volume is responsible for the increase in blood volume during first 2 weeks:
Two Phases leading to increased Plasma Volume:
Phase 1: Increases in plasma proteins
* Intense exercise → proteins (albumin) leave vascular space (into interstitial fluid) → ↑ number of proteins returned through lymph system → results in rapid plasma volume increase within the first hour of recovery form the first training bout
Phase 2: Increased protein synthesis
* Upregulation of protein synthesis with repeated exercise (↑ADH, ↑aldosterone)
* Increased reabsorption of water and sodium in kidneys increases plasma volume
↑ADH → ↑ H2O reabsorption
↑Aldosterone → ↑ Na+ reabsorption (water follows)
Recall: ↑Plasma volume → ↑EDV → ↑SV
Mitochondrial Quality improved by exercise training: (role of PGC-1α)?
Training → ↑biogenesis of new Mito; ↓ degradation of Mito; clears damaged Mito (mitophagy)
PGC-1α expression enhanced by both endurance and resistance training
* Regulatory protein involved in
(1) MIT biogenesis and
(2) replacement of old weakened MIT
Improves capacity to generate ATP by oxidative phosphorylation
Metabolic Adaptations to Training
Lactate threshold adaptations to endurance training:
Training: can exercise at a higher percentage of VO2max before lactate begins to accumulate in the blood
-↑ MIT oxidative enxymes, MIT size and number → increased MIT capacity to generate ATP aerobically → ↑ Lactate Threshold
* Allows trained person to sustain a high percentage of aerobic capacity during prolonged
exercise without accumulating blood lactate
Lactate threshold (LT)→ the exercise intensity or relative intensity at which blood lactate begins to increase above baseline concentration
* The point at which during incremental exercise lactate production exceeds the rate of lactate clearance or removal
Aerobic/endurance training induces intracellular changes that enhance a muscle fiber’s capacity to aerobically generate ATP
Fat Catabolism: changes with endurance training
Fat catabolism:
* Increased ability to oxidize FA (triacylglycerols stored within active muscle during steady-rate exercise)
* Facilitated release of FA from adipose tissue, higher quantity of fat-mobilizing enzymes
- Can exercise at higher absolute level of submax before fatigue occurs from glycogen depletion
Biochemical changes (increased MIT enzyme activity) drive FA oxidation (Decrease RER)
Carbohydrate catabolism: changes with endurance exercise?
Carbohydrate catabolism:
* Increased ability to oxidize carbohydrate (pyruvate)
Important:
1) provides faster aerobic capacity than from fat breakdown
2) liberates 6% more energy than fat
(Review: Fat provides more energy than CHO but more O2 needed to oxidize fat than CHO)
Integrated Adaptations to Chronic Endurance Exercise
During maximal exercise CO increases considerably and is largely responsible for the increase in ?
Increased maximal CO is the result of the increase in maximal ? that occurs with training induced changes in cardiac structure and function
VO2max = CO x (a-v)O2difference = rate of oxygen consumption
During maximal exercise CO increases considerably and is largely responsible for the increase in VO2max
Increased maximal CO is the result of the increase in maximal SV that occurs with training induced changes in cardiac structure and function
