A pilot study of high-intensity interval training in older adults with treatment naive chronic lymphocytic leukemia
Question
Is 12 weeks of supervised HIIT combined with muscle endurance resistance training feasible and associated with physical fitness and immune-function changes in older adults with treatment naive chronic lymphocytic leukemia?
Summary
In a small nonrandomized pilot study of older adults with untreated chronic lymphocytic leukemia, 12 weeks of supervised treadmill HIIT plus resistance training was feasible, achieved high adherence, caused no exercise-session adverse events, and was associated with larger strength and immune-cell function changes than non-exercising controls. Aerobic fitness did not clearly improve more than control.
Methodology
- Adults with stable treatment naive chronic lymphocytic leukemia who completed the 12-week study.
- 16 participants.
- Treadmill walking intervals plus leg press, chest press, and seated row.
- Work intervals: 60-90 s high-intensity intervals after acclimation.
- Recovery: 60-90 s active recovery.
- Intensity: 80-90% VO2 reserve/peak for high intervals; 50-60% for recovery.
- 30 min HIIT; two sessions/week also included 30 min resistance training.
- 3 HIIT sessions/week and 2 resistance sessions/week.
- 12 weeks.
- Two-arm quasi-experimental pilot study
- Feasibility and adherence, Safety, Aerobic capacity, and Muscle strength were tracked.
Outcomes
Feasibility
HIIT completers met feasibility, fidelity, and compliance criteria with 99% prescribed minutes completed.
5.0 +/- 0.2 sessions/week; 99 +/- 3.6% prescribed minutes; 100% completed >80% high-intensity intervals at prescribed HR.
Strength
Leg press, chest press, and seated row strength increased more in HIIT than control.
HIIT vs control: leg +35.4%, g=2.52; chest +56.1%, g=1.15; seated row +39.5%, g=3.07.
Aerobic capacity
HIIT did not outperform control for aerobic capacity.
Post-HIIT aerobic capacity was 3.8% lower than controls; g=0.49. Authors noted HIIT increased about 5.3% while controls increased about 10.3%.
NK function
NK-cell cytolytic activity and cytotoxic protein expression were higher after HIIT versus control.
K562 +20.3%, g=1.43; OSU-CLL +3.0%, g=0.95; autologous B-cells +14.6%, g=1.30; granzyme B g=1.56.
Insights
- For selected older clinical users, walking HIIT can be delivered by raising treadmill grade while keeping speed at walking pace.
- High adherence in this study depended on supervision, screening, flexible scheduling, and symptom-aware load changes.
- This study should not be used to claim that HIIT improves aerobic capacity more than usual activity in CLL.
Limitations
- Small pilot sample
- Nonrandomized allocation by travel distance
- Combined HIIT and resistance training prevents isolating the active ingredient
- Participants were screened and may not represent the broader CLL population with higher comorbidity burden
- No p-values were reported because of recruitment bias
- Possible control contamination
Safety
- No adverse events were recorded during exercise sessions.
- All HIIT participants reported minor muscle soreness early in training, considered a normal reaction.
- Arm edema, knee pain, upper respiratory infection, groin tenderness, and mild foot pain each led to brief rescheduling and reduced load until resolved within less than 1 week.
- One participant had dizziness and nausea more than 3 h after baseline CPET and went to the emergency department; clinicians deemed CPET not causal and allowed study continuation.
- The sample was screened to exclude abnormal CPET cardiac findings, absolute exercise contraindications, orthopedic limitations, diabetes, COPD, and uncontrolled hypertension.