# A pilot study to assess the feasibility of a remotely monitored high-intensity interval training program prior to allogeneic hematopoietic stem cell transplantation PMID: 38032994 Journal: PloS one Published: 2023-11-30 Authors: Artese AL, Winthrop HM, Bohannon L, Lew MV, Johnson E, MacDonald G, Ren Y, Pastva AM, Hall KS, Wischmeyer PE, Macleod D, Molinger J, Barth S, Jung SH, Cohen HJ, Bartlett DB, Sung AD ## Question Can a home-based, mobile-health-supported HIIT program be feasibly and safely implemented before allogeneic hematopoietic stem cell transplantation, and are there preliminary improvements in cardiorespiratory fitness and physical function? ## Summary This single-arm pilot tested whether adults preparing for allogeneic hematopoietic stem cell transplantation could perform a home-based, remotely monitored HIIT program before transplant. Participants were prescribed three 30-minute sessions per week with 1-minute high-intensity and 1-minute low-intensity intervals tracked by Apple Watch. Among participants who engaged with the program, adherence was high, no HIIT-related adverse events were reported, and cardiorespiratory fitness and functional measures improved, but the study was small, non-randomized, and had substantial missing wearable data. ## Population - Adults scheduled for allogeneic hematopoietic stem cell transplantation for malignant or non-malignant hematologic disorders - Sample size: 13 - Age: 58.8 +/- 11.6 years; range 34.2-76.4 - Sex: 10 male, 3 female - Fitness level: Very low baseline cardiorespiratory fitness in adherent participants; baseline VO2peak for men 15.9 +/- 3.0 and women 15.0 +/- 3.1 mL/kg/min - Health status: Pre-allogeneic HCT patients; baseline BMI 29.5 +/- 4.8 kg/m2; cardiology clearance after CPET required ## Methodology - Single-arm pilot feasibility intervention study - Variable pre-HCT period; adherent participants completed 3.0-26.0 weeks of HIIT, mean 13.8 +/- 7.5 weeks - Baseline and post assessments at Duke Adult Bone Marrow Transplant clinic; exercise primarily home-based or participant-selected location with remote monitoring and weekly exercise physiologist check-ins ## Protocol - Home-based remotely monitored HIIT. - Modality: Self-selected aerobic activity such as walking, jogging, stair climbing, or cycling. - Work intervals: 1 minute at 80-90% HRR. - Recovery: 1 minute at 50-60% HRR. - Sets or repetitions: 10 high/low interval pairs prescribed after 5-minute warmup and before 5-minute cooldown. - Intensity: HRR-based, individualized from CPET maximum HR and resting HR; HR captured by Apple Watch. - Session duration: 30 minutes. - Frequency: 3 sessions/week, non-consecutive when possible. - Program length: Variable pre-HCT period; mean 13.8 +/- 7.5 weeks among adherent participants. - Progression: Initial 1-2 week build-up to 10 intervals; no further formal progression. ## Outcomes ### Retention and session adherence Status: improved Nine of 13 participants (69.2%) consistently reported sessions and remained engaged; among these, median session adherence was 100% and average weekly sessions were 3.1 +/- 0.8. Median adherence 100% (IQR 87-107); entire sample prescribed-session adherence 73 +/- 53%. ### Interval/intensity adherence Status: mixed Adherent participants averaged 9.2 of 10 prescribed intervals and met or exceeded high-intensity HR on most intervals, but low-intensity recovery targets were less consistently achieved and HR data were missing for 27.5% of reported sessions. Completed intervals 9.2 +/- 2.3/session; high intervals >=80% HRR on 68.8 +/- 34.8% of intervals; high intervals 80-90% HRR on 25.5 +/- 17.8% and >90% HRR on 43.3 +/- 30.4%; low intervals at 50-60% HRR on 33.0 +/- 15.7%; HR data retrieved from 72.5% of reported sessions. ### VO2peak Status: improved VO2peak increased from baseline to sign-off among participants with post CPET data. 14.6 +/- 3.1 to 17.9 +/- 3.3 mL/kg/min; p<0.001. In adherent participants: 14.9 +/- 3.3 to 18.0 +/- 3.6; p=0.002. ### Physical function Status: improved Among adherent participants, 30-second sit-to-stand and SPPB chair-stand performance improved; 6MWT improvement exceeded a clinically meaningful threshold used in other populations. 30-second sit-to-stand 13.8 +/- 1.5 to 18.3 +/- 3.3 repetitions; 6MWT 514.4 +/- 43.2 to 564.6 +/- 19.3 m; table/discussion report clinically meaningful 50.1 m mean improvement. ### Safety Status: no clear change No HIIT-related adverse events were reported. One high resting HR episode related to atrial fibrillation was cleared by physician; other missed sessions were attributed to cancer/treatment effects rather than HIIT. ## Practical Insights - Remote HIIT can be made measurable by tracking interval count, high-zone attainment, recovery-zone attainment, and data retrieval, not just attendance. - A 30-minute session with 10 minutes of hard work may be feasible for selected, medically cleared clinical users when individualized by HRR and supported by coaching. - Non-participation is a major issue even when adherent users do well; onboarding, fatigue management, and fallback lower-intensity options are important. - Wearable HR data quality is an operational dependency for remote HIIT fidelity. ## Limitations - Single-arm non-randomized pilot with no comparator. - Small sample size and trial stopped before planned enrollment because of COVID-19 and funding timeline. - Only 9 of 13 participants provided analyzable intervention adherence data. - HR data were missing for 27.5% of reported sessions. - Intervention length varied according to clinical transplant timing. - Mostly male sample, limiting generalizability to female patients. - Prior exercise experience and outside activity were not measured. - Three enrolled participants did not ultimately undergo HCT due to relapse. ## Safety And Adherence - No adverse events related to HIIT were reported. - One participant had abnormally high resting HR related to atrial fibrillation during one week and continued exercising after physician clearance. - Cancer/treatment-related missed-session causes included chemotherapy fatigue, hospital admission, pain, and blood clot. - Clinical users required CPET and cardiology clearance before participation. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/38032994/) (pubmed) - [DOI](https://doi.org/10.1371/journal.pone.0293171) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10688680/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.