Pulmonary Exercise Physiology Flashcards
What is anaerobic threshold?
VO2 at which anaerobic energy production begins to supplement the aerobic energy system
The point during graded exercise that a greater rate of energy production is required than what can be met by the aerobic system.
How is anaerobic threshold measured?
Disproportionate increase in lactate accumluation in blood and ventilatory parameters during exercise on increasing intensity
What are the major aspects of lactate threshold?
1) Lactate Threshold
- Phase during graded exercise when blood lactate exhibits an abrupt increase
2) OBLA
- point of further increase in blood lactate (greater than 4.0mM)
What causes LT?
Increase in required anaerobic glycolytic supply to contribute to total energy needs Increase epinephrine (stimulate glycogenolysis) Blood shunt causing vasoconstriction in non-working tissue
What are the 2 major aspects of ventilatory threshold?
1) Ventilatory threshold
phase when VE increases disproportionately in relation to VO2
2) Respiratory Compensation
Process of respiratory assistance in buffering anaerobically generated H+ via bicarbonate reaction
What are other methods of identifying VT?
V-shaped slope
Ventilatory equivalent for VO2 (VE/VO2)
Ventilatory equivalent for VCO2 (VE/VCO2)
Excess CO2 elimination
What causes VT?
Increase in perception of energy demand by respiratory center in the brain resulting in increased VE
Increased afferent neural activity from muscle and joint receptors
Increase H+ and CO2 level that stimulate chempreceptors and stimulate an increase in VE
What is the link between VT and LT?
Increase H+ and CO2 levels
Stimulation of central and peripheral chemorecptors
Both stimulate and increase in VE
Does LT cause VT?
No
How can VT occur without an LT?
primary neural factors that stimulate ventilation and are not directly dependent on anaerobic stimulation of the chemoreceptors
LT does not necessarily cause VT
Is AT important?
YES especially for endurance athlete
AT is highly correlated with performance times
AT is a quantifiable setting for aerobic endurance training
Does VE limit Exercise?
Not likely in healthy individuals because the lung is over built for exercise (greater capacity than what is used)
Limiting factor under some environmental conditions and in combination with some medical conditions
What are ventilation training results?
1) VE is somewhat lower at rest and is lower during sub-maximal exercise (greater efficiency and lower afferent neural activity, greater aerobic capacity)
2) VE max is increased with endurance training (higher overall cardiorespiratory training (higher VO2max requires higher VE
Does AT respond to training?
There is an increase in the speed, PO and VO2 at AT after training which enhances performance Due to: increase oxidative capacity of skeletal muscles increase in lactate and H+ removal rate glycogen sparing increase fat oxidation Increase O2 delivery Delay FT Delay epinephrine release
What is the function of the pulmonary system?
Supply O2
Remove CO2
Assist with regulation of acd-base balance
What is inspiration?
Increase in thoracic cavity due to downward contraction of the diaphragm Lifting and rotating of the rib cage by the scaleni and external intercostals Causes a drop in pressure in the lung Allows the air to flow in
What is expiration?
VE is due to relaxation of the diaphragm and scaleni and external intercostal
During rest it is a passive recoil of lung and related tissue
During exercise the internal intercostals and abdominal assist
Increase in intrapulmonic pressure pushes air out of the lung
What are static volumes?
Measured through forced vital capacity which is the total amount of air that can be expired after a full inspiration