Feasibility and acceptability of an mHealth, home-based exercise intervention in colorectal cancer survivors: A pilot randomized controlled trial
Question
Is a remotely monitored, home-based mHealth exercise intervention that includes a HIIT prescription feasible and acceptable for stage II-III colorectal cancer survivors within five years after resection and adjuvant therapy?
Summary
This small pilot randomized controlled trial tested a 12-week home-based mHealth exercise intervention in stage II-III colorectal cancer survivors after surgery and adjuvant therapy. Participants were randomized to HIIT or moderate-intensity continuous exercise, remotely monitored with Polar devices. Retention was 100%, workout completion averaged 88.6%, and no adverse events were reported, but only two participants were assigned to HIIT and adherence to the prescribed HIIT heart-rate zones was low because participants often exceeded the target zones.
Methodology
- Stage II-III colorectal cancer survivors less than five years post-resection and adjuvant chemotherapy, recruited from Huntsman Cancer Institute clinics.
- 7 participants.
- Self-selected weight-bearing aerobic exercise, including walking, jogging, elliptical, or calisthenic exercise.
- Work intervals: Five 4-minute intervals at 85-90% peak HR.
- Recovery: Four-minute active recovery at 50-75% peak HR after each high-intensity interval.
- Intensity: 85-90% peak HR for intervals; 50-75% peak HR warmup and recovery.
- 50 minutes.
- 4 workouts per week.
- 12 weeks.
- Pilot parallel randomized controlled trial.
- Feasibility, Acceptability, Safety, and Body composition were tracked.
Outcomes
Workout completion
Participants completed a high proportion of prescribed workouts across both intervention groups.
Mean completion 88.6%; 95% CI 79.4-97.8; range 63-100%.
Retention and safety
Retention was complete and no adverse events were reported.
100% retention; no adverse events.
HIIT HR-zone adherence
HIIT participants did not meet the prespecified HR-zone adherence benchmark; adherence was low for high-intensity and active recovery intervals because HR often exceeded prescribed zones.
HIIT adherence: 28.8% for high-intensity intervals and 51% for active recovery intervals; feasibility benchmark was >=75% of participants adhering to prescription.
Acceptability
Qualitative responses supported acceptability, including accountability, motivation, autonomy, improved quality of life, and plans to continue exercising.
Qualitative thematic analysis; all participants noted plans to continue exercise.
Health outcomes
Descriptive health outcomes were mixed and underpowered; the study was not designed to establish efficacy.
HIIT n=2 and MICE n=5; peak aerobic capacity not analyzed due to limited paired testing under COVID-19 restrictions.
Insights
- For clinical or post-treatment users, HIIT should be framed around medical screening, HR monitoring, conservative zone targets, and supervision/escalation rules.
- Remote monitoring plus weekly follow-up can support completion, but HR-zone adherence may require better real-time coaching.
- User autonomy and self-selected modality may improve acceptability in home-based exercise programs.
Limitations
- Very small pilot sample, especially HIIT group with n=2.
- Trial ended early because of COVID-19 recruitment and assessment disruptions.
- Homogeneous sample: all non-Hispanic White and married.
- Peak aerobic capacity change was not analyzed due to limited paired cardiopulmonary tests.
- Remote HR measurement had possible lag when changing intensity, potentially affecting adherence estimates.
- Clinical population limits direct translation to unscreened general consumers.
Safety
- No adverse events were reported.
- Eligibility excluded recurrent disease, uncontrolled resting blood pressure, mobility limitations requiring assistive devices, and known or symptomatic cardiometabolic/renal disease.
- Baseline cardiopulmonary testing used 12-lead ECG and blood-pressure monitoring.