Exam 1 Flashcards
(33 cards)
is critical power superior to the lactate anaerobic threshold? why?
yes. Critical power is a correlate and a DETERMINANT of performance
- lactate anaerobic threshold is only a predictor or correlate not a good determinant
what causes blood lactate to increase during exercise?
Ra increases more rapidly than Rd of lactate in the blood
At VO2 max what are the oxygen pressures inside the exercising muscle fibers? Low or zero?
low ; 2-3 mmHg
Owels point
a critical metabolic level was found below which there was no increase in blood lactate as a result f exercise, although above this level such an increase did occur
- the critical level varies for different subjects and for the same subject for different types of exercise
is the lactate threshold a determinant of athletic performance or it is just related to it? How about critical power?
- lactate threshold- NOT A DETERMINANT just a correlate
- critical power- IS A DETERMINANT of athletic performance
when does lactate begin to accumulate in the blood?
lactate increases pre and post training below VO2 max
-it is increasing even at levels with no anaerobiosis
What are the fick equations
VO2= VE(FiO2-FeO2) (sampled from the mouth) VO2= Q (CaO2-CvO2) (sampled from pulmonary artery
understand the O2 cascade from room air to muscle tissue during exercise? what are the approximate values?
from room air to muscle tissue O2 is diffused
150 mmHg room air, 100 mmHg lungs, Resting muscle PO2 ~34 torr, max exercise PO2 ~3 torr
If I am a 102 year old woman, what organ system is likely to fail first? what is the physiological significance?
- Lung will fail first
- Diffusion limitation meaning have the inability to get O2 from the lung into the blood
Is VO2 max determined by the delivery of O2 via the blood or diffusion of blood into muscle tissue
diffusion of blood into muscle tissue
In the O2 cascade from room air to muscle tissue what did Professor John B west predict resting Po2 was?
~30 torr
what tool did Dr. Richardson use to actually measure resting and max exercise PO2?
MRI (magnetic residence spectroscopy)
what is the PO2 in tissue during max exercise? at rest?
exercise:~3 torr
at rest: 34 torr
what are some mediators of IR injury?
Oxidants/ROS calcium calpain caspase 3 decreased ATP
what are some mediators of IR injury?
Oxidants/ROS calcium calpain caspase 3 decreased ATP
cardioprotection
protecting the heart against IR injury
IR injury
lack of blood causing a dysfunction in cardiac heart muscle
Myokines
cytokines and other peptides that are produced, expressed and released by muscle fibers and exert either paracrine or endocrine effects (myokines are produced in muscle cells)
give examples of myokines we learned about
IL-6
IL15
BDNF
Irisin
what exercise intensity gives the greatest cardioprotection? Why is it important for the clinical setting?
No differences between 50% and 70% VO2
easier for people to exercise at 50%
how long does cardioprotection last after cessation of training?
9-18 days
what are some potential mechanisms of cardioprotection?
endoplasmic reticulum stress proteins HSP's cyclooxygenase inducible NOS cytosolic antioxidants (SOD and SOD2) sarcolemmal K+ channel?
how does doxorubicin chemotherapy contribute to the development of heart failure?
- oxidative stress is the key mediator/contributor to heart failure
- causes an increase in free radical production in mitochondria because heart and skeletal muscle cells have a lot of mitochondria in it making the heart a target
- increase in radicals results in: damage to DNA, organelle damage, damage to protein, cell death
how does doxorubicin chemotherapy contribute to the development of heart failure?
- oxidative stress is the key mediator/contributor to heart failure
- causes an increase in free radical production in mitochondria because heart and skeletal muscle cells have a lot of mitochondria in it making the heart a target
- increase in radicals results in: damage to DNA, organelle damage, damage to protein, cell death
