Week 4 readings summary

Question 1

what conditions appear more common in older athletes compared with their inactive peers ??????????

Answer 1

atrial fibrillation
myocardial fibrosis
coronary artery calcification

Question 2

what did Morris study on buses show?

Answer 2

Morris - conductors on London’s double-decker buses had a lower risk of sudden cardiac death (SCD) than the physically inactive bus drivers

Question 3

PA recommendations

Answer 3

Recommendation - recommend that adults perform moderate-intensity exercise for a minimum of 30 min daily at least 5 days a week, or vigorous intensity exercise for a minimum of 20 min daily at least 3 days a week

Question 4

what does SCD stand for?

Answer 4

sudden cardiac death

Question 5

what is SCD?

Answer 5

There is general consensus that vigorous exercise acutely, albeit transiently (Short term), increases the risk of SCD, but only in individuals with underlying cardiac disease, either occult or manifest

Question 6

conclusion about SCD

Answer 6

The observations that the risk of SCD increases during moderate or vigorous exercise, but that habitual exercise also decreases the SCD risk again suggests, as in PHS, that exercise acutely increases, but ultimately decreases, the risk of SCD

Question 7

why may young die?

Answer 7

Young individuals may die during exercise due to inherited or congenital cardiac conditions e.g. hypertrophic cardiomyopathy, coronary artery anomalies and RV cardiomyopathy

Question 8

why may old die?

Answer 8

Older individuals due during exercise primarily from coronary artery disease (CAD). Acute atherosclerotic plaque erosion or rupture leading to acute coronary thrombosis is detected in most, but not all, previously asymptomatic individuals who die or suffer a myocardial infarction during exercise.

Question 9

following endurance exercise there is a decrease in LV ejection fraction, why does this occur?

Answer 9

Decrease in blood volume reducing cardiac preload reducing ventricular performance without directly altering cardiac contractility

Exercise producing myocardial dysfunction independent of volume changes

Cardiac damage

Question 10

what indicates cardiac dysfunction?

Answer 10

Decreases in LV systolic strain

Absolute peak systolic twist post exercise

Question 11

examples of biomarkers

Answer 11

creatine kinase
cardiac troponins
BNP and NT-proBNP

Question 12

role of creatine kinase

Answer 12

Catalyses the transfer of a phosphate group from creatine phosphate to ADP producing ATP, composed of 2 sub units creating three isoforms

Question 13

who has increased CK?

Answer 13

marathon runners

Question 14

what do high levels of cardiac troponin indicate?

Answer 14

High troponin levels can indicate a problem with the heart. The heart releases troponin into the blood following an injury, such as a heart attack. Very high troponin levels usually mean that a person has recently had a heart attack. The medical term for this attack is myocardial infarction

Question 15

when are levels of CT elevated?

Answer 15

Endurance exercise

Question 16

when are levels of CT greater?

Answer 16

with age
presence of CV risk factors
running experience
increase exercise duration
exercise intensity
dehydration

Question 17

what is the strongest single predictor of cardiac troponin release?

Answer 17

intensity

Question 18

mechanisms behind increase in cardiac troponins

Answer 18

Increase in cardiomyocyte membrane permeability

Production of oxidative radicals

Preload-induced increases in stretch responsive integrins

Question 19

what are BNP and NT-proBNP?

Answer 19

Hormones produced in the hearts ventricles constantly in response to cardiomyocyte stress produced by volume or pressure overload

Question 20

what do increased levels of BNP and NT-proBNP indicate?

Answer 20

cardiac dysfunction

Question 21

magnitude of increase of BNP and NT-proBNP depends on what?

Answer 21

duration

Question 22

cardiac adaptations due to long term exercise training

Answer 22

increases in parasympathetic tone and sympathetic tone

enlargement of all 4 chambers

Question 23

implications of cardiac adaptation from long term exercise on cardiac dimensions and function

Answer 23

The possibility that increased LV and RV dimensions from exercise training contribute to cardiac disease in a minority of susceptible individuals

Question 24

other possible maladaptation’s of lifelong exercise

Answer 24

bradycardia
long QT
aortic size and root dilation

Question 25

risk factors of atrial fibrillation

Answer 25

age

increased LA size/pressure e.g. hypertension

Question 26

what is long QT?

Answer 26

Longer interval between depolarization and repolarization of cardiac ventricles

Question 27

what is aortic size and root dilation?

Answer 27

Aortic dissection and rupture are rare, but can cause sudden death and the risk of this increases with increase aortic size and root dilation