As the heart rapidly slows during recovery from exercise, PVCs commonly occur and usually have no clinical significance. This may be a time when metabolic adjustments in the heart are somewhat inappropriate and therefore, occasionally serious disturbances in rhythm may be initiated. A recent report, however, suggests that the danger from arrhythmias during the cool down may be considerable. The levels of epinephrine and nor epinephrine can shoot up to 10 times of the normal. Hormonal fluctuations can be minimized by a gradual cool down. The drop in blood pressure during recovery appears to trigger the response. Even young patients without established heart disease occasionally have ventricular tachycardia or even ventricular fibrillation after exercise.