Vulnerability of pulmonary capillaries during severe exercise.

The article analyzes the vulnerability of pulmonary capillaries to mechanical failure during strenuous exercise. Such mechanical failures are possible when the capillary wall stresses as a result of severe exercise. This can cause the integrity of the blood-gas barrier to break the stress. The exercise induced pulmonary hemorrhage in the galloping racehorses is an example for capillary stress failure. The pulmonary artery wedge pressures can rise to 30 mm Hg during intense exercise while giving an induced strain to the capillary walls.