Cardiopulmonary Response to Activity Flashcards
Tidal volume
Air moved during the inspiratory or expiratory phase of each breathing cycle, 0.4-1.0 L
Inspiratory Reserve Volume
Inspiring as deeply as possible following a normal inspiration; 2.5-3.5 L above tidal
Expiratory Reserve Volume
Volume that can be expired after normal expiration; 1-1.5L more
Residual Lung Volume
Air volume remaining in lungs after exhaling as deeply as possible; Increases with age; allows uninterrupted exchange of gases
RLV + FVC =
Total Lung Capacity
Minute Ventilation
Average 6 L (Breathing rate*Tidal Volume)
Can be increased by increasing rate or depth of breathing
Breathing rate can increase to ____ bpm during strenuous exercise
35-45; 60-70 elite endurance athletes
Tidal volumes for trained and untrained individuals rarely exceed _____ of vital capacity
60%
Alveolar Ventilation
Portion of inspired air reaching the alveoli and participating in gas exchange
Anatomic deadspace
Remaining 150-200 ml of air that does not enter alveoli
Amount of inspired air that mixes with existing alveolar air with tidal inspiration
~350 ml
Ventilation-Perfusion ratio
The ratio of alveolar ventilation to pulmonary blood flow
Average of .84
Intense exercise: 5.0
Ventilatory Equivalent
Describes the ratio of minute ventilation to oxygen consumption
Usually 25 L during submaximal exercise
VO2 Max
Maximal oxygen consumption
O2 comsumption plateaus or increases slightly with additional intensity
Phase I of minute ventilation
Neurogenic stimuli from the cerebral cortex and feedback from the limbs stimulate the medulla to increase ventilation abruptly
Phase II of minute ventilation
After a short plateau minute ventilation rises exponentially to achieve a steady level with gas exchange demands
Phase III of minute ventilation
Fine-tuning of the steady state ventilation through peripheral sensory feedback
The abrupt decline in ventilation when exercise ceases reflects
Removal of the central command drive
Sensory input from previously active muscles
The slower recovery phase results from
Gradual diminution of the short-term potentiation of the respiratory center
Reestablishment of the body’s norms
Light to Moderate exercise effect on ventilation
Increases linearly with O2 consumption and CO2 production
Average 20-25 L of air for each L of O2 consumed
Mainly increased through tidal volume
More intense sub-maximal exercise effect on ventilation
Minute ventilation moves sharply upward disproportionately to O2 consumption
Can attain 35-40L of air breathed per L of O2 consumed
Lactate Threshold
The highest O2 consumption or exercise intensity achieved with less than 1.0 mM increase in blood lactate concentration above the pre-exercise level
OBLA
Onset of blood lactate accumulation
(Blood lactate conc. increases to 4.0 mM
4 factors affecting lactate threshold
- Imbalance between rate of glycolysis and aerobic respiration
- Decreased redox potential
- Lower blood O2
- Lower blood flow to skeletal muscles
OBLA uses
Provides submaximal exercise measure of aerobic fitness
Occurs without significant metabolic acidosis or cardiovascular strain
Acid-Base Buffering of the ventilatory system
Intense exercise leads to imbalance between glycolytic and aerobic systems
- Causes excess H+
- H+ stimulates increase in alveolar ventilation
- CO2 gets blown off
Pumonary Ventilation take home
Increases in ventilation directly proportional to increase O2 consumption, except at extremely high intensities
Suggests that ventilation is regulated more by the need to remove CO2
Pulmonary ventilation with aerobic training
May be reduced by 25% w/ submaximal exercise
May increase maximal minute ventilation by 25%
Pulmonary diffusion capacity improves
Blood lactate levels throughout sub-maximal levels are ____ secondary to training
Reduced
VO2 max may ______ by 10-30% with moderate endurance training
Increase
