Cardioresp adaption to exercise

Question 1

why is exercise important?

Answer 1

• lowers risk of CVS disease
  exercise testing is the basis for the functional evaluation of the cardio-resp system

Question 2

Describe the 2 different types of muscle

Answer 2

• slow twitch - type I - dependent on oxidative phosphorlylation, lots of mitochondria and myoglobin, mainly postural but also some used in endurance events
• fast twitch - type IIa and type IIb - relies on creatine phosphate to regenerate ATP, large amount of glycolytic enzymes, used in spirnting and explosive events

Question 3

how is exercise intensity defined in terms of oxygen uptake?

Answer 3

• in dynamic exercise, oxygen consumption increases with work in a linear manner
• resting oxygen consumption - 250mls/min, moderate - 1000mls/min etc

Question 4

what is the reason for the increased O2 consumption in exercise?

Answer 4

the replacement of ATP

Question 5

what is the maxinal O2 consumption called?

Answer 5

the VO2 max

Question 6

define the VO2 max

Answer 6

the** maximum rate **at which the heart, lungs, and muscles can effectively use oxygen during exercise, used as a way of measuring a person’s individual aerobic capacity.

Question 7

compare the values for a typical, trained and elite VO2 max

ml/min/kg - units

Answer 7

• typical VO2 max - 4ml/min/kg
• trained VO2 max - 6ml/min/kg
• elite VO2 max - 8ml/min/kg

Question 8

what 3 aspects does O2 delivery depend on?

Answer 8

• getting 02 into the body and blood -respiration
• getting O2 from the** lungs to the tissues** (cardiovascular delivery)
  getting o2 from the blood to the** respiring tissues** (O2 extraction)

Question 9

what occurs to the O2 and C02 production in exercise?

Answer 9

they both increase

Question 10

do arterial blood gases change in moderate exercise?

Answer 10

no

Question 11

which states of CO2, o2 & ph would be expected to increase ventilation?

Answer 11

• high C02
• low O2
• low PH

Question 12

what triggers the increase in ventilation at higher O2 consumptions?

Answer 12

low PH

Question 13

what is the anaerobic threshold?

Answer 13

• when the demand for O2 exceeds the delivery of O2

Question 14

increased HR is a feature of exercise, wahat branch of the ANS is involved in stimulating an increase in HR?

Answer 14

the sympathetic system

Question 15

during exercise, describe the adaptions that are made to the CV system & what system activates this?

Answer 15

• driven by the sympathetic NS
• increase in cardiac output and redistribution of blood flow
• increased venous return and therefore SV- due to increased muscle pump, resp pump and venoconstriction
• increased contractility of the heart driven by SNS

Question 16

why does the stroke volume decrease at high work loads?

Answer 16

• the faster the heart beats, the less time there is too fill the ventricles
• preload is too low due to decreased ventircular filling time

Question 17

what does the SNS do to blood vessels?

Answer 17

causes vasoconstriction

Question 18

what does the increased metabolite production (CO2, K+, H+ & adenosine) do to the blood vessels?

Answer 18

• vasodilation

Question 19

in exercisem oxygen has to get from the lungs into the blood, in the blood to the tissues and from the blood into the tissues .. which of these limits performance?

Answer 19

• transport in blood from lungs to tissue

Question 20

define O2 dept

Answer 20

• The amount of oxygen required to remove the lactic acid, and replace the body’s reserves of oxygen, is called the oxygen debt

Question 21

what 3 stages in oxygen debt incurred?

Answer 21

• depletion of ATP
• depletion of creatine phosphate
• build up of lactic acid

Question 22

what are the effects of training on muscle?

Answer 22

• increase** muscle strength and resistance to fatigue **
• muscle** hypertrophy -** increased muscle diameter
  * possible shift in muscle fibre type - between type I and type II
• increased glycolytic and oxidative capacity - increased ATP, mitochondrial enzymes etc

Question 23

what are the cardioresp effects of training?

Answer 23

• bradycardia- slowed HR
• increased ventricle size and SV so stroke volume and cardiac output remain the same
• reduced blood pressure
• increased levels of myoglobin & a,3 BPG - which facilitates better O2 delivery

Question 24

what are examples of things that training will not improve?

Answer 24

• VO2 or the cardiac output at rest
• diffusing capacity or the haemoglobin concentration
• max HR

Question 25

describe the distribution of Cardiac output during exercise to different regions of the body including muscles, heart, GIT & kidneys

Answer 25

• there is sympathetic stimulation - which causes vasoconstriction
• there is an increase in resistance overall in the vessels due to the sympathetic system, areas like the GIT and kidneys experience lower blood flow due to the increased resistance
• in areas like the heart and the muscles, metabolites eg adenosine - will override the sympathetic vasoconstriction and there will be increased blood flow to these regions