Exercise Physio Flashcards
What is used as an index of energy expenditure? What is the resting rate? What is the term MET?
Oxygen consumption (VdotO2); 250 ml/min; metabolic equivalent (3.5 ml/min/kg)
How can you determine the types of fuels being utilized? What can this knowledge help you determine?
RQ, which is VCO2/VO2; caloric equivalent of 1 L of O2
What is the RQ of carb oxidation? Fat oxidation? What does this correspond with in terms of Kcal/L O2? What is the most efficient means of calorie storage in the body?
1; .7; 5.05 in carbs, 4.70 in fats; Fats at 9.1 Kcal/gm
How can you measure RQ? When is it equal to respiratory exchange ratio?
O2 consumed at the mouth as well as CO2 production; O2 content is constant and total CO2 content stays constant
What is a rough approx of caloric expenditure? What is the expenditure for a 70 kg person performing a 3.0 MET activity for one hour?
VdotO2 x 5.0 kcal/L; 210 Kcals approx
How can we measure inspired and expired air volume? How do you get VdotO2? How do you report the volumes?
Flow meter with O2 and CO2 gas analyzers; VI x FiO2 - VE x FeO2; STPD
How does O2 consumption correlate with work rate? What happens at really high work rates?
With increased VdotO2, this is corresponding to different work rates and eventually there is a steady state when O2 supply = O2 demand; you cannot increase O2 consumption any further, meaning you’ve hit VdotO2 max
What is the relationship between O2 consumption and exercise intensity? What is required at supramaximal work loads? What is VO2 max a good measure of?
Linear relationship; NOT an increase in O2 consumption, but requires anaerobic component such that fatigue sets in quicker; aerobic fitness/endurance performance (like marathon runners)
What are the phases of exercising?
Linear phase, ventilatory threshold (ventilation increasing out of proportion with exercise intensity), and then exponential phase
In the graph of total ventilation vs. percent max VdotO2, what happens with all the pressures? What happens during exponential phase to pH? Why?
Arterial and aveolar pressures of O2 are stable, arterial CO2 pressure will only dip during exponential phase, venous CO2 will increase steadily and venous O2 decreases steadily; It dips with at higher intensity exercise because you rely on anaerobic mechanisms and have lactic acidosis
What is the relationship of CO with VdotO2?
It’s linear, meaning cardiac output goes up as work intensity increases
What is the relationship of heart rate with work intensity? What distorts the initial HR?
Fairly linear, with symps inputting to SA node and decreased parasymp input; anticipatory “resting” HR
What is SV equal to? What happens with it as exercise intensity increases?
End-diastolic volume - end-systolic volume; increases initially with mild-moderate exercise, but with increased intensity SV levels out or even decreases because of decreased filling time of the ventricles (lower EDV) and ESV progressively at a greater rate than EDV
How is CO distributed with exercise? What is receiving less output?
More can go to skeletal muscle (arteriole control diverting 80-85% of CO to skeletal muscle); GI is an example (splanchnic) because of vasoconstriction
At the capillaries, what is extraction of O2 at rest? What happens during more intense exercise with arterial O2 and venous O2? Why (3 reasons)?
~5 mL; arterial O2 is about the same, but venous O2 can drop off since you’re delivering more to the tissues (ie skeletal muscle); better cap perfusion, decreased myocyte PO2 (gradient), and right shift in O2-Hb dissociation curve which promotes O2 unloading!!!
