Reproducibility of maximal exercise test data in the HERITAGE Family study

Purpose: The reproducibility of responses to maximal cycle ergometer testin g was determined using data from the HERITAGE Family study at four Clinical Centers in the United Stales and Canada. Methods: Reproducibility was dete rmined from maximal exercise test data obtained a) on 2 d in a sample of 39 0 subjects (198 men and 192 women), b) across 4 d in an Intracenter Quality Control (ICQC) substudy with 55 subjects who were not part of the main stu dy, and c) across 2 wk in a Traveling Crew Quality Control (TCQC) substudy with the same eight subjects who were tested at each of the four centers. R eproducibility was evaluated using technical errors, coefficients of variat ion (CV) for repeated measures, and intraclass correlation coefficients (IC C) for selected variables obtained on the main cohort, as well as on the IC QC and TCQC substudies. Results: With the exception of systolic and diastol ic blood pressures and respiratory exchange ratio, all the other variables (heart rate, ventilation, (V) over dotO(2), and (V) over dotCO(2)) were hig hly reproducible, with CV below 10% and ICC over 0.86. These results were s imilar to those previously reported on the same subjects at a submaximal po wer output associated with 60% (V) over dotO(2max). Results were consistent for the main cohort, the ICQC sample, the TCQC sample, and across all four Clinical Centers. Conclusions: Day-to-day variations are small and reprodu cibility is high for maximal values of heart rate, ventilation, (V) over do tO(2) and (V) over dotCO(2) at each of the four Clinical Centers of the HER ITAGE Family Study.