acute risk during exercise is transiently elevated -> know the numbers
especially in undiagnosed cardiovascular disease (especially older athletes with coronary disease) have congenital/cardiomyopathic conditions (younger athletes)
they had underlying diseases and were exposed to high levels of activity and stress
young athletes who died were affected by silent CV diseases
sport activity is not a cause of the increased mortality, but as a trigger on those with a vulnerable substrate
vulnerable substrate +
you need oxygen for repolarisation
Vigorous exercise in combination with vulnerable substrate produces a series of reactions:
The cause of the reactions can be anything that causes ischemia or that makes the heart susceptible to ischemia/faster repolarization of cardiac cells
release of thromboxane A2 and other coronary vasoconstrictors
enhanced blood coagulation
increased blood lactate concentrations (lactic acidosis) which results in acid/base disturbances
Intra- and extracellular electrolyte derangements
Increased serum free fatty acid concentrations
Excessive rise in body temperature
Dehydration
Role of type and intensity
Impact of age
Exercise paradox - exercise as a trigger, yet also a preventative measure
Interviews with 1228 patients conducted an average of four days after myocardial infarction provided data on:
usual annual frequency of physical activity
time, type, and intensity of physical exertion in the 26 hours before the onset of myocardial infarction.
RR of MI after physical exertion was 5.9 compared with less strenuous physical exertion
inactive coronary artery disease patients had 2.4-fold increased risk for sudden cardiac death compared with active patients
in subgroup analysis among symptomatic patients, the risk of sudden cardiac death was 7.4-fold in highly active and 3.6-fold in inactive patients compared with active patients
The results emphasize the importance of further functional evaluation for ischemia and probably more aggressive treatment in patients with ongoing significant angina before frequent intense exercise training.
