Medical Problems in Athletes
Sudden cardiac death and screening
Cardiac causes dominate sudden death in athletes. Under 35 years, inherited cardiomyopathies (hypertrophic cardiomyopathy in many series, arrhythmogenic right ventricular cardiomyopathy), congenital coronary anomalies, ion channelopathies (long QT, Brugada, CPVT) and myocarditis predominate; over 35, atherosclerotic coronary disease. Screening with history, examination and resting ECG is used in some countries, but a normal ECG does not exclude every condition.
Red flags in syncope: exertional syncope, syncope without prodrome, family history of sudden death under 40, known cardiomyopathy, palpitations with syncope.
Respiratory
Exercise-induced bronchoconstriction causes cough, wheeze and breathlessness 5–15 minutes after exercise and needs objective confirmation (bronchial challenge or eucapnic voluntary hyperpnoea). Vocal cord dysfunction mimics asthma with inspiratory stridor and a negative challenge.
Endocrine and metabolic
Type 1 diabetes requires individualised carbohydrate and insulin plans around exercise; hypoglycaemia is the acute risk. Relative energy deficiency in sport affects bone, menstrual function, immunity and performance.
Environmental and haematological
Exercise-associated hyponatraemia results from overdrinking with non-osmotic ADH release; symptomatic cases need hypertonic (3%) saline and fluid restriction, not more isotonic fluid. Sickle cell trait raises the risk of exertional collapse with rhabdomyolysis.
Traps: the "neck check" - symptoms above the neck allow light exercise; fever, myalgia or systemic symptoms mean no exercise. Exertional heat stroke (core >40 °C with CNS dysfunction) is treated by immediate cold-water immersion.