Excessive shortness of breath with exercise, exercise-associated wheeze or cough, diminished exercise performance

Pre- and postexercise pulmonary function tests may reveal diagnosis

Short-acting inhaled beta agonist 15 to 20 minutes before exercise, refractory period with short vigorous bouts of exercise 15 to 20 minutes before event

More severe cases require individualized treatment

Collapse after vigorous endurance exercise

Most cases are benign, related to transient pooling of blood in lower extremities

One severe form is related to dilutional hyponatremia secondary to overzealous hydration with hypotonic fluids

Differential diagnosis includes heat-related illness and cardiovascular etiologies

Elevation of feet and legs for collapse related to pooling of blood in legs

Hyponatremia must be recognized appropriately, then treated expertly (beyond scope of this article); may be preventable if athletes avoid overhydration, particularly in women and in slower, inexperienced athletes

Decreased exercise performance, fatigue, “heavy legs,” poor sleep, mood disturbance

Symptoms persist despite more than two weeks of rest

No specific serologic markers

Rule out other medical causes of fatigue

Rest for weeks to months, then gradually resume training program