Frontiers in Cardiovascular Medicine · Nov 7, 2026
Exploring Differences of the Six-Minute Walk Test and CPET in Evaluating High-Intensity Training Outcomes in Cardiac Rehabilitation
By Rebekah J McCoy, Jordan K Parks, Casey L Filler et al.
Introduction: The six-minute walk distance test (6MWT) is used to assess functional capacity and guide exercise prescription (ExRx) in cardiac rehabilitation (CR). However, changes in 6MWT distance may not fully characterize changes in maximal aerobic capacity following CR, particularly when comparing different ExRx. Purpose: Compare changes in functional walking performance and maximal aerobic capacity among CR patients participating in high-intensity interval training (HIIT) compared to moderate intensity steady state exercise (MISS). Methods: This observational study compared changes in 6MWT and CPET performance from pre- to post-CR in patients undergoing HIIT or MISS. Fifty-eight patients, 61 ± 11 years, completed 23-36 CR sessions. All 35 HIIT and 23 MISS participants performed a 6MWT and symptom-limited CPET at baseline and completion of CR. Results: HIIT showed greater improvements in CPET-derived outcomes of VO2PEAK and workload (eMETs) at peak compared to MISS (Peak VO2PEAK: 2.24±3.51 vs. -0.36±4.29 mL/kg/min, p= 0.014; Peak eMETs: 1.71±1.53 vs. 0.36±2.19, p= 0.007, HIIT vs. MISS respectively). Both groups demonstrated improvement in 6MWT distance (346.75±212.34 vs. 285.61±195.86 ft, p= 0.274, HIIT vs. MISS respectively). Change in 6MWT was not correlated to change in VO2PEAK for either group (r=-0.085, p=0.626 vs. r=0.125, p=0.570, HIIT vs. MISS). Conclusions: Both training groups demonstrated improvements in 6MWD; however, the magnitude of improvement did not differ significantly between them. The CPET demonstrated greater functional gains in the HIIT vs. MISS trained individuals. When evaluating physiological benefits of different training intensities, these findings suggest reliance on 6MWT alone may underestimate training response and limit exercise prescription in contemporary CR programs.