Physical and immunological benefits of strength training in older adults with treatment naive chronic lymphocytic leukemia: ADRENALINE pilot study

Objectives Chronic lymphocytic leukemia (CLL) patients often experience reduced physical activity due to disease-related symptoms. Structured resistance training may support physical fitness and immune function. This pilot study evaluated the feasibility and preliminary effects of a 16-week strength-based resistance training program in treatment-naïve CLL patients. Methods Eleven patients (65.6 ± 9.7 years) were randomized to a resistance training group (REx, n = 4) or a usual care control group (CG, n = 7). REx completed two weekly sessions, including a 10-minute cycling warm-up, 45-min machine-based full-body resistance training (∼80% 1-RM), and 5-min cycling cooldown. Outcomes included body composition, muscle strength, aerobic capacity, and selected hematologic markers. Hedges’ g was used to estimate effect sizes (small 0.2, medium 0.5, large ≥ 0.8). Results The intervention was safe and fully adhered to by participants. Compared with controls, REx showed large effect sizes for knee flexion torque (g = 1.12) and agonist/antagonist ratio (g = 1.74), reductions in body fat percentage (g = −1.00), and favorable changes in neutrophil counts (g = −1.28). Aerobic capacity showed minimal change (g = −0.33). Conclusions These findings suggest that a 16-week, strength-based resistance training program is feasible in treatment-naïve CLL patients and may positively influence muscle strength, body composition, and selected immune parameters. Larger studies are warranted to confirm these observations and evaluate potential clinical benefits. Trial registration Registered at ClinicalTrials.gov.