PMID 41704018

Research
All papers

The effect of two remote exercise programs on cardiorespiratory fitness, cardiac function, and vascular health in patients with breast cancer

Weeldreyer NR, Ellison CC, Mabalot MB, Helms CE, Nealy ZB, Leicht ZS, Abbate A, Brenin CM, Dillon PM, Millard T, Krukowski RA, Zoellner JM, Angadi SS

Question

Do remotely delivered HIIT and moderate-intensity exercise programs differ in preserving cardiorespiratory fitness, cardiac function, and vascular function when started before and continued through chemotherapy for breast cancer?

Summary

This randomized trial compared two remotely monitored exercise programs in women with breast cancer undergoing chemotherapy: home-based recumbent-bike HIIT and walking-based moderate-intensity exercise. Fifteen of 24 enrolled patients completed all aspects of the study. VO2peak declined significantly in the moderate-intensity group but not the HIIT group, although between-group differences were not statistically significant and the study was underpowered because dropout was higher than expected. Adherence averaged about 61%-64%, chemotherapy side effects were the main reason for noncompliance, and no exercise-related serious adverse events were reported.

Methodology

  • Patients with breast cancer scheduled for chemotherapy and cleared by physicians for exercise.
  • 24 participants.
  • Stationary recumbent bicycle.
  • Work intervals: Four 4-minute intervals at 85%-90% peak heart rate; alternatives were eight 2-minute intervals or five 3-minute intervals.
  • Recovery: 3-minute active recovery at about 50% peak heart rate in the standard protocol; alternatives used 2-minute or 3-minute recovery.
  • Intensity: 85%-90% peak heart rate for work intervals.
  • About 40 minutes for standard 4x4 with 10-minute warmup, three 3-minute recoveries, and 5-minute cool down.
  • 3 days per week.
  • Throughout chemotherapy; mean 10.6 +/- 3.8 weeks in HIIT.
  • Randomized trial comparing two remote exercise interventions during chemotherapy.
  • VO2peak, Cardiac function, Vascular outcomes, and Exercise adherence were tracked.

Outcomes

VO2peak

VO2peak declined significantly within MOD and did not significantly decline within HIIT, but the between-group difference was not statistically significant.

MOD 1.50 +/- 0.23 to 1.27 +/- 0.28 L/min, p=0.013, d=1.2; HIIT 1.58 +/- 0.24 to 1.52 +/- 0.28 L/min, p=0.445, d=0.3; between-group p=0.109, d=0.9.

Mixed

Oxygen uptake efficiency slope

OUES significantly declined in MOD but not HIIT; between-group difference was not significant but had a large effect size.

MOD 1.63 +/- 0.27 to 1.29 +/- 0.26 L/min, p=0.002, d=2.5; HIIT 1.57 +/- 0.20 to 1.42 +/- 0.23 L/min, p=0.15, d=0.6; between-group p=0.14, d=0.9.

Mixed

Cardiac function

No significant between-group differences in cardiac function; HIIT cardiac output increased significantly within group.

HIIT cardiac output 4.3 +/- 1.1 to 5.3 +/- 1.0 L/min, p=0.004; between-group cardiac output p=0.097.

Mixed

Blood pressure and arterial stiffness

MOD showed significant central systolic blood pressure reduction and Aix75 reduction; between-group difference was significant for Aix75 only.

MOD central SBP 111 +/- 4.9 to 104 +/- 4 mmHg, p=0.008; Aix75 between-group p=0.040.

Mixed

Safety

No exercise-related serious adverse events were reported in either group.

No clear change

Insights

  • Remote HIIT can be structured with heart-rate monitoring, equipment setup, and fallback interval options, but adherence may still be limited during chemotherapy.
  • For clinical populations, safety messaging should require physician clearance and contraindication screening before HIIT.
  • Underpowered between-group results should be framed as suggestive preservation of VO2peak, not definitive HIIT superiority.

Limitations

  • Greater than anticipated dropout made the study underpowered.
  • No true non-exercise control group.
  • Different modalities between groups and cycle-based testing may confound intensity with modality specificity.
  • All African American participants were in the HIIT group by chance.
  • Echocardiography limitations may affect cardiac-function measurement.
  • Broad chemotherapy regimen inclusion may have muted cardiotoxicity-related findings.

Safety

  • No exercise-related serious adverse events were reported in either group.
  • Physician clearance was required before exercise training.
  • The trial used extensive exclusion criteria for cardiac, pulmonary, vascular, metabolic, retinal, and other risk conditions.