An athlete may collapse after exertion. This may be caused by a variety of conditions.
Exercise-associated collapse may be associated with:
(1) hypertrophic cardiomyopathy
(2) coronary artery anomaly
(3) malignant ventricular arrhythmia
(4) myocarditis
(5) atherosclerotic cardiac disease
(6) exercise-induced anaphylaxis
(7) exercise-associated hyponatremia
(8) hypoglycemia
(9) dehydration
(10) heat illness
(11) hypothermia
(12) cerebral encephalopathy
(13) intracranial aneurysm
(14) drug-induced hyperthermia
(15) sickle cell disease
(16) Marfan's syndrome
(17) rhabdomyolysis
(18) asthma or exercise-associated bronchospasm
(19) exercise-associated postural hypotension
(20) no obvious underlying cause
The reason for collapse when there is no cause identified is uncertain. Some possible explanations include:
(1) the reflex of Barcroft and Edholm (onset of low right atrial pressure triggers a skeletal muscle vasodilator reflex resulting in sudden hypotension)
(2) other cardiac baroreflex
(3) cerebral hypoperfusion due to peripheral pooling of blood.