Exercise Physiology Exam 2

ATP-PCr Performance Tests aim to measure _

Intramuscular ATP-PCr size, PCr depletion rate

Common ATP-PCr Performance Tests

Stair-sprinting, Jumping, Any form of “sprint” (6-8 seconds)

_ provides the most common indicator of short-intermediate-term (anaerobic) energy system activation

Blood lactate level

Anaerobic testing is often limited by _

Participant motivation

Common Anaerobic Power Performance Tests

<3 minute bouts of exercise that are sport-specific (e.g. high-rep set for a bodybuilder or Wingate for a cyclist)

Blood lactate levels don’t reflect absolute energy transfer because _

Some lactate is always being used to generate ATP

Sprint Training Effects

Higher levels of muscle/blood lactate, Greater depletion of muscle glycogen during exercise

Muscle fatigue/discomfort is caused by _ and _, not _

H+, Interstitial potassium build-up, Lactate

Fick Equation

VO₂ = CO * (Ateriovenous-VO₂Difference)

VO₂ increases _ with submaximal exercise intensity and _ with maximal exercise

Linearly, Levels off

Secondary Indices of VO₂ Max

RER>1.15

HR within 10% of age-predicted maximum

Lactate accumulation (7-8mM)

VO₂ at sub-maximal exercise intensity is _ between untrained and trained individuals

About the same

Resting VO₂

~0.25L/minute

Key variable accounting for large VO_2-max differences between humans

Body weight

Weight loss with no change in physical activity often causes absolute VO2-Max to _ and relative VO2-Max to _

Decrease, Increase

Most Common Aerobic Performance Test

VO_2-Max

Movement Economy Definition

How much oxygen is consumed during a steady-state task (easily converted into calories/unit time)

Movement Efficiency Equation

[Power (Watts → kcals/hr -→ kcals) / (Energy expenditure)] * 100

Movement Economy Equation

Relative VO₂ / Running Speed

Walking economy is equal to running economy at about _

5MPH

Respiratory Zone

Respiratory bronchioles, Alveoli

Conducting Zones (respiration)

Hyoid, Larynx, Trachea, Bronchus, Bronchioles

Tidal Volume Definition

Volume inspired or expired during normal ventilation

Tidal Volume Population Norm

0.5L

Total Lung Capacity Definition

Volume in lungs after maximal inspiration

Total Lung Capacity Population Norm

5L

Residual Volume Definition

Volume in lungs after maximum expiration

Residual Volume Population Norm

1L

Anatomic Dead Space

Airway space “prior” to alveoli where gas exchange doesn’t occur

Physiologic Dead Space

Airway space within alveoli where gas exchange does not occur

Obstructive lung diseases make it difficult to _ while restrictive lung diseases make it difficult to _

Exhale all air in the lungs, Fill the lungs with air

Minute Ventilation Normative Values (Rest)

Breathing Rate: 12

TV: 0.5L

V_E: 6L/minute

Minute Ventilation Normative Values (Exercise)

Breathing Rate: 50

TV: 2L

V_E: 100L/min

During exercise, physiologic dead space in the alveoli _ due to _

Becomes active, Increased perfusion

Epinephrine increases respiratory volume during exercise via _

Bronchiole dilation

Effects of endurance training on V_E

Decreased V_E at any given VO₂

Increased TV

Decreased breathing rate (greater extraction of O₂ from each round of air in lungs)

%O₂ in atmosphere (constant value)

~21%

Lung PO₂ and PCO₂ _ during exercise

Remain constant (100mmHg and 40mmHg)

Venous Blood PO₂ and PCO₂

40mmHg and 46 mmHg

During high-intensity exercise, muscle PO₂ can reach _ and PCO₂ can reach _

3mmHg, 90mmHg

1g of Hb carries _ mL of O₂

1.34mL

Bohr Effect

Increased temperature, Lower pH, and Increased CO₂ cause better Hb delivery

Normal respiration is regulated by the _

Medulla

Humoral Regulators of Ventilation

PO₂, PCO₂, Acidity (peripheral chemoreceptors)

Non-Chemical Regulators of Ventilation

Anticipatory response, Motor cortex, Proprioceptors, Lung tissue receptors

In the initial stages of exercise, ventilation is primarily controlled _

Non-chemically (motor cortex and mechanoreceptors)

A few minutes into exercise, ventilation is controlled by _

Both humoral and non-chemical methods

During steady-state exercise, ventilation is controlled by _

Primarily humoral methods (“fine-tuning”)

At low intensities, ventilation increases primarily due to _

At higher intensities, ventilation is further increased by _

Increased tidal volume

Increased breathing rate

Ventilatory Threshold

Intensity at which minute ventilation increases disproportionately to VO₂

Ventilatory threshold occurs at roughly the same time as _

Lactate threshold

Do ventilation or CV factors more frequently limit endurance performance?

CV factors

Heart’s “natural pacemaker”

Sinoatrial Node

P-wave represents _

Atrial depolarization

QRS Complex represents _

Ventricular depolarization

T-wave represents _

Ventricular relaxation

“Central command” regulator of HR is _ via _

Ventrolateral medulla, The vagus nerve

Effect of Training on HR (rest)

Lower HR (increased vagal tone)

“Downside” of change in HR caused by training

Have to work harder to achieve same response

2 Classic HR Equations (not Karvonen)

220-age

208-(0.7*age)

CO increases _ in response to increasing submaximal exercise intensity

Linearly

Maximum stroke volume occurs at _

50% VO_2-Max

Factors which affect stroke volume

1) Cardiac filling (from venous return)

2) Resistance of blood flow out of ventricle

3) Contractility (Frank-Starling from muscle pump)

Arterial O₂ _ in response to increasing exercise intensities

Venous O₂ _ in response to increasing exercise intensities

Stays the same

Increases

During exercise, CO increases from ~_ to ~_

5L/min, 25L/min

Distribution of blood flow during exercise is regulated by _

Vasodilation or constriction of blood vessels to “active” or “inactive” tissues

Normal arterial BP during systole is _ and during diastole is _

MAP is _

120, 70-80

~90mmHg

BP is primarily regulated through _

TPR alterations (vasoconstriction and vasodilation)

During moderate exercise, systolic BP _ and diastolic BP _

During near-maximal exercise, systolic BP _ and diastolic BP _

Increases, Stays constant

Increases, Increases

Nitric oxide is primarily used as a _

Vasodilator

Steps for local control of vasodilation

1) Endothelial cells undergo shear stress from increased blood flow

2) Endothelial cells produce Nitric Oxide

3) NO diffuses to nearby smooth muscle cell and relaxes them, increasing vessel volume

The heart extracts roughly _% of Hb-bound O₂ and skeletal muscle extracts roughly _%

80, 25

Rate-Pressure Product

The amount of work the heart is doing (Systolic BP * HR)

How long does it take for plasma volume to increase in response to aerobic training?

Short-term adaptation (1-2 weeks of only a few sessions per week)

Initial increases in vascular volume in response to endurance training come from _ before _ catches up

Plasma volume increases, RBC content

Cardiac Hypertrophy (Athlete’s Heart) is usually _ in aerobic athletes and _ in strength athletes

Eccentric (unable to fully eject blood), Concentric (excessive pressure)

The major adaptation which increases VO_2-Max is _

Increased CO from increased SV_max

From fastest to slowest, sort these detraining effects: Plasma Volume, SV_Max, VO_2-Max, A-V(O₂)diff

Plasma Volume decrease, VO_2-Max decrease, SV_Max decrease, A-V(O₂)diff decrease

_ AMP is produced for a trained individual than an untrained individual within the same duration of contractile activity

Less

Why does a trained individual use less glucose/glycogen than an untrained individual?

Decreased alarm response (less epi and AMP) to same exercise stimulus

What training intensity/duration has the greatest impact on mitochondrial density?

Mid-long-term (40-60 minutes) of moderate-high intensity

What factors regulate the increase in mitochondrial density associated with exercise?

Exercise-induced Ca²⁺ and AMPK increases

Markers for increased mitochondrial density

PGC-1 Alpha and Cytochrome C

Training causes a _ in IMTG, making them _ to mitochondria

Increase, Closer in proximity

Training Principles (5)

Specificity, Overload, Individual Differences, Reversibility, Initial Fitness Level

Ceiling Principle

The idea that rate of improvement slows to nearly zero in a trained individual as they approach their genetic ceiling

Overload is varied by altering _

Intensity, Frequency, or Duration of exercise

Most important variable to monitor/adjust in a training program

Intensity

Aerobic capacity improves between _ and _ % of HR maximum
This is about _% of VO_2-Max

55, 70

50

VO_2-Max Heritability is roughly _%, with the maternal contribution making up _ % of this heritable portion

50, 60

Physical methods of heat loss during exercise

Conduction, Convection, Radiation, Evaporation

The body’s physiological thermostat is the _ which detects changes in temperature via _

Hypothalamus, Thermal receptors and blood perfusion

The primary physiological response to increasing temperature is _

Vasodilation and increased perfusion of the skin

Cardiovascular Drift

Decrease in SV and increase in HR (maintain constant CO) when exercising in the heat

Why does cardiovascular drift occur?

Blood flow to skin increases causes decreased venous return, decreasing SV

Common medical problems which arise due to exercise in the heat

Heat cramps, Heat exhaustion, Heat stroke

Heat acclimatization consists of _

Decreased HR, Decreased change in body temperature, Increased sweat rate

Primary issue of altitude stress

Decreased PO₂ due to decreased barometric pressure (%O₂ is same as sea level)

Acute responses to altitude exposure

Increased breathing rate, Increased CO (HR up/SV down), Reduced plasma volume, Decreased maximal oxygen consumption
Increased BMR, Increased catecholamines, Increased glycolysis