Cardiac Effects of a Competitive Road Race in Trained Child Runners

Abstract

ABSTRACT.Background. Animal studies and investigations of adult endurance athletes indicate a transient depression of myocardial function after prolonged highintensity exercise.Purpose. To determine whether a similar decrease is observed in child distance runners after a 4-km competitive road race.Methods. Anthropometric measures, resting M-mode echocardiograms, maximal cycle exercise tests with estimation of cardiac output, and electrocardiograms were performed before a 4-km road race in nine run-trained boys (mean age, 12.2 years). Weight and resting echocardiogram and electrocardiogram were assessed immediately after the race. The entire test battery was repeated 24 hours later.Results. Small but significant decreases in mean body weight and left ventricular end-diastolic dimension were observed immediately after the race, but there were no changes in shortening fraction. These findings are consistent with the effects of dehydration. Measurements returned to prerace values by 24 hours of recovery. Peak work capacity, maximal stroke volume, and maximal cardiac output were similar on prerace and 24-hourpostrace testing. No electrocardiographic abnormalities were observed.Conclusions. No adverse cardiac effects were observed from a competitive 4-km road race in male child distance runners. Pediatrics 1997;100(3). URL: http:// www.pediatrics.org/cgi/content/full/100/3/e2; echocardiography, children, exercise.ABBREVIATIONS. LVSF, left ventricular shortening fraction; VTI, velocity time integral; LVED, left ventricular end diastolic dimension; bpm, beats per minute.T he emergence of the elite-level child athlete has raised concern regarding possible adverse physiologic and psychologic effects of intense sports training and competition during the growing years.1 Little scientific data are available, however, to evaluate the reality of these potential risks. Consequently, creating appropriate guidelines for safe participation by children in competitive sports remains difficult.Evidence does exist that high-intensity sports may impose significant acute stress on the cardiovascular system. Echocardiographic evidence of myocardial dysfunction immediately after competition in prolonged distance running events has been demonstrated in adult endurance athletes.2,3 This depressed contractility, manifested as a decrease in left ventricular shortening fraction (LVSF), typically resolves within 24 hours after a race. Findings of left ventricular dysfunction after sustained running have also been corroborated in the laboratory setting.4 Animal studies support the concept that transient myocardial fatigue after sustained high-intensity exercise may be expressed as depressed contractility, possibly related to alterations in calcium transport capacity of the sarcoplasmic reticulum. 5,6 This study was performed to determine whether cardiac functional alterations are evident after shorter distance competitions in trained child runners. Resting electrocardiograms and two-dimensional echocardiograms were performed before and immediate...

Effect of Repeated Endurance Runs on Cardiac Biomarkers and Function in Adolescents

“…Rowland et al (24) reported no changes in LV function after a 4-km run (~15 min) in trained boys; however, the duration was considerably shorter than that used in the cunent study. Within the present study, postexercise changes in LV systolic (EF) and diastolic (E:A) function were statistically significant but small and noncumulative with EF after exercise still within normal limits (19,35).…”

The Effect of Hydration Status on the Echocardiographic Measurements of Normal Cats

“…Volume depletion produced reductions in both diastolic and systolic chamber dimensions such that FS% was unchanged. Studies of human patients treated with furosemide, 32,33 hemodialysis, 34 or dehydrated by exercise 35 demonstrated reduced diastolic LV chamber dimension without concomitant effects on systolic chamber dimension. However, phlebotomized infants 36 and pigs 16,37 develop reductions in both LV diastolic and systolic dimensions.…”

Cardiac Responses to Exercise in Child Distance Runners

“…By responses to a questionnaire, none of the runners nor controls had yet experienced pubertal signs of voice change, appearance of pubic hair, or growth spurt. The runners were included in a previous report of echocardiographic changes following a road race (19). and the controls were involved in a study comparing cardiovascular responses to exercise in children and adults (22).…”