cardiovascular drift
occurs during longer periods of exercise, the hr increases to make up for the decrease in stroke volume because of fatigue or dehydration
CO differences between endurance athlete and sedentary person
sedentary people will have a higher resting heart rate as they have to work harder to move blood throughout the body, their stroke volume is also not very high.
endurance athletes will have a lower resting heart rate and a higher stroke volume because their heart works better so they would have a higher max cardiac output
effects of the frank-starling mechanism during physical activity
there is a more powerful ejection stroke proportional to the force of contraction which follows the mechanism and allows for more blood to be pumped through the heart when needed in a time like physical activity
average cardiac output for male and female
male - approx. 5L per min
female - approx. 4L per min
mechanism that could increase SV during exercise
- enhanced cardiac filling in diastole with a bigger systole contraction
- normal filling with more forceful ejection and emptying during systole
- training adaptations that expand blood volume
why do adult females and teenagers have 10% larger cardiac output than males while exercising
because of their 10% lower Hb concentration
factors that increase avo2 difference during exercise
- decrease pvo2
- right shift of O2 hb curve
mechanisms for increased SV with training
- increased blood volume (increased diastolic filling)
- increased preload (starling)
- increased contractility (greater systolic emptying)
upper body exercise results in max O2 consumption approx. ___ - ___% lower than lower body exercise
20-30%
power output with ______ body exercise provides greater physiologic strain than ______ body
upper & lower
