Heart rate and metabolic response to competitive squash in veteran players: identification of risk factors for sudden cardiac death.

We studied 10 older males during a competitive game and the early post-exercise period to define the metabolic response to squash in veteran players. For comparison, all subjects were also studied during exhaustive treadmill exercise. Squash caused a dramatic increase in heart rate (150%), and circulating levels of noradrenaline (164%), adrenaline (93%), lactate (202%) and free fatty acids (67%). These effects were independent of haemoconcentration. The early post-exercise period (5 min) was characterized by persistent elevation of plasma catecholamines, lactate, and free fatty acids, hypokalaemia and ventricular arrhythmias. The heart rate and metabolic responses to squash were similar in pattern and magnitude to those observed during treadmill exercise, highlighting the strenuous nature of squash as a recreation sport. While these changes may represent appropriate physiological adaptation to exercise in health, each has been implicated in the pathogenesis of fatal ventricular arrhythmias in subjects with ischaemic heart disease. These data support the contention that squash may be an inappropriate form of exercise for older men with coronary artery disease.