Safety and Feasibility of Long-Term High-Intensity Interval Training With and Without Peer Support in Cancer Survivors
Question
Are 12 months of HIIT, with or without peer support, safe and feasible for breast, prostate, and colorectal cancer survivors after a supervised HIIT introduction?
Summary
In 137 cancer survivors, a 4-week supervised cycling HIIT start followed by 12 months of community gym access was safe by the study's criteria, with no serious adverse events and few minor adverse events. People usually used the prescribed bike mode and completed the intended high-intensity duration, but long-term attendance and intensity targets were hard to maintain, and peer support did not clearly solve that.
Methodology
- Breast, prostate, and colorectal cancer survivors not undergoing active cancer therapy
- 137 participants.
- Cycle ergometer/Wattbike.
- Work intervals: 4 minutes at 85-95% HRpeak.
- Recovery: 3 minutes at 50-70% HRpeak.
- Intensity: 85-95% HRpeak for intervals.
- 38 minutes.
- 3 sessions/week prescribed.
- 4 weeks supervised plus 12 months maintenance.
- Randomized controlled feasibility and safety trial with supervised preintervention phase
- Adverse events, Frequency adherence, Intensity adherence, and Peer support contact were tracked.
Outcomes
Safety
Long-term HIIT met safety criteria with no serious adverse events and few minor adverse events.
0 SAEs; 7 grade 1/2 AEs, about 0.5%.
Attendance
Attendance criteria were not met during the 12-month maintenance phase.
A priori attendance threshold was not met in either group.
Intensity
Long-term high-intensity zone adherence was below target in both groups.
48% HIIT+PS and 40% HIIT-only achieved prescribed intensity; average HR was 83.4% and 80.7% HRpeak.
Mode adherence
Participants overwhelmingly used the prescribed cycle ergometer mode.
99.0% of sessions completed on Wattbikes.
Peer support
Peer contact frequency was feasible and safe but did not clearly improve overall HIIT feasibility.
0.8 contacts/week, about 40 contacts/participant; no peer-support adverse events.
Insights
- Safety can be good while long-term adherence still fails on frequency and intensity.
- Track frequency, intensity, duration, and mode separately instead of one adherence score.
- Peer support is not a substitute for feedback, supervision, or intensity calibration.
Limitations
- Limited demographic and cancer-type diversity.
- COVID-19 disrupted recruitment, delivery, and retention.
- Adverse events were partly self-reported and may be underestimated.
- Peer contact logs were paper-based and incomplete.
- Cycle-based results may not translate to bodyweight HIIT.
Safety
- No serious adverse events were reported.
- Seven grade 1/2 adverse events were reported.
- Postexercise hypotension was the most frequent adverse event.
- Most adverse events occurred during the supervised preintervention phase.
- No adverse events or psychological distress were attributed to peer support.