CARDIORESPIRATORY RESPONSES TO EXERCISE

Question 1

Heart rate, stroke volume and cardiac output response

Answer 1

Heart rate - is directly proportional to exercise under near max is reached. HR plateaus
SV - increases with intensities up to 40-60% of Vo2 max, remains unchanged up to and including exhaustion
CO - Is the result of SV and HR. Increases with intensity

Question 2

HRmax

What is the indirect measurements and their limitations

Answer 2

HRmax = 208 - (0.7 X AGE in years) or 220 - age in years
HRmax = 220 - age in years
Big standard deviation when using age

Question 3

Explain why the ability to increase stroke volume is important in determining
maximal oxygen consumption.

Answer 3

Stroke volume is important in determining maximal oxygen consumption as it has three main stages such as preload, contractibility and afterload. These three stages influence how much blood is pumped from the left ventricle per beat
SV only increases to its highest value during submax exercise

Question 4

What is the fick principle?

Answer 4

VO2 = Q x (a-v) O2 difference 
Vo2 = HRx SV x (a-v) o2 difference 

States that oxygen consumption of a tissue is dependent on blood flow to that tissue and the amount of oxygen extracted from the blood by the tissue. Using different tissues relies on more work done by the muscles depending on the area, meaning the body must use more energy to keep up with demand

Question 5

Frank-Starling Mechanism

Answer 5

Increased force of contraction, allowing increased venous return and better ventricular filling. Greater contracility with actin and myosin cross-bridges developing greater stretch. Systole volume is increased during exercise due to this as the ventricle is able to stretch

Question 6

Blood pressure response to exercise

Answer 6

Systolic BP increase is proportional to exercise intensity
Diastolic BP slight decrease or slight increase at max
Correlated to MAP

Question 7

Cardiovascular drift

Answer 7

High core temp and dehydration due to exercising in a hot environment
Low SV = high skin blood flow, low plasma volume
low venous return/preload
Reduces EDV
HR drift overcomes this top compensate CO

Question 8

How does pulmonary ventilation respond to increasing intensities of exercise?

Answer 8

More co2 and H+ is generated enhancing oxygen unloading in the muscle
right arterial stretch receptors, chemoreceptors to inspiratory centre

Question 9

Role of respiratory system in acid-base

Answer 9

Ventilation helps H+ bind to bicarbonate, increasing blood pH, neutralising exercise acidosis