Exercise to Boost Immune Function in CLL

Published 2026-01-18 · cll, chronic lymphocytic leukemia · MyCBC Blog

Exercise to Boost Immune Function in CLL: A Practical Guide to HIIT and Strength Training for Older Adults

People living with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) often ask whether exercise can help their immune system. While CLL directly affects immune cells and raises infection risk, growing clinical evidence indicates that targeted exercise programs—especially a combination of high-intensity interval training and resistance work—can safely improve physical fitness and measurable immune activity in many older adults with CLL. This article explains why exercise matters, what types of programs are most promising, how to start safely, and practical sample sessions and progressions.

Why exercise matters for people with CLL

CLL impairs immune function in several ways. The cancer arises from B lymphocytes and disrupts antibody production. T-cell function and elements of the innate immune system can also be altered. As a result, infections are more likely and vaccine responses can be reduced.

Exercise supports immune health through multiple mechanisms:

• Improves muscle mass and strength, which aids mobility, reduces fall risk, and supports recovery from treatments.
• Modulates immune cell activity, including temporary increases in natural killer cell function and improved circulating immune surveillance after structured workouts.
• Enhances cardiovascular fitness and metabolic health, reducing risks from comorbid conditions that increase infection complications.
• Supports mental health and sleep, both important for immune resilience.

Types of exercise most relevant to CLL

The two evidence-aligned approaches are:

• High-intensity interval training (HIIT). Short bursts of high effort alternated with recovery. Properly tailored HIIT can trigger beneficial immune responses and improve functional fitness in shorter sessions.
• Resistance (strength) training. Progressive weight or bodyweight exercises increase muscle strength and endurance, and complement HIIT to preserve lean mass and improve daily function.

What HIIT looks like for older adults

HIIT does not mean sprinting until exhaustion. For older adults, and for people with CLL, HIIT is adapted to current fitness and health status. Intervals commonly range from 30 to 90 seconds at a hard effort, with 1.5 to 3 minutes of active recovery. Total interval work plus recovery often totals 15 to 25 minutes, with warm-up and cooldown bringing the whole session to about 45 to 60 minutes when combined with strength work.

Evidence summary: what research shows so far

Early clinical studies and small pilot trials in older adults with CLL have shown:

• Improved muscle strength after supervised programs combining HIIT and resistance training.
• Increased activity of natural killer cells in laboratory tests following a supervised exercise program, suggesting enhanced innate immune activity.
• Feasibility and safety when participants are screened and sessions are supervised by trained staff.

These results are encouraging but preliminary. Larger trials are needed to determine long-term effects on infection rates, vaccine responses, or disease course. Exercise remains a supportive strategy to improve resilience, fitness, and quality of life.

Safety first: screening and precautions

Before starting a HIIT or resistance program, follow a safety checklist:

• Medical clearance from the oncology team and primary care physician. Discuss current treatments, recent infections, and cardiovascular history.
• Cardiac screening for people with known heart disease or recent cardiac events. A cardiopulmonary exercise test or ECG-guided clearance may be recommended for higher-risk individuals.
• Blood count considerations. Low platelet count, severe anemia, or very low neutrophils require exercise modification. Typical clinical thresholds used by many centers:
  • Platelets < 50,000 per µL: avoid heavy resistance and high-risk activities.
  • Platelets < 20,000 per µL: avoid resistance training and contact risk; consult hematology.
  • Hemoglobin < 8 to 10 g/dL: avoid intense aerobic sessions until evaluated.
  • Absolute neutrophil count < 1.0 x 10^9/L: increased infection risk. Avoid group gym exposure and seek advice.
• Active infections or fever: do not exercise until cleared.
• Adjust for treatment side effects. Fatigue, neuropathy, joint pain, or fluid shifts related to therapy require individualized programming.

How to monitor intensity safely

Use practical measures to judge effort:

• Heart rate. Estimate maximum heart rate as 220 minus age, then target short work intervals at roughly 75 to 85 percent of that maximum for HIIT. Note that medications such as beta blockers alter heart rate response.
• Rate of perceived exertion (RPE). The Borg scale (0 to 10) is useful: aim for 7 to 8 during high-intensity intervals and 3 to 4 during recovery if heart rate is unreliable.
• Talk test. During high-intensity intervals, speaking a full sentence should be difficult. During recovery, conversation should be possible.

Sample 12-week program for older adults with CLL

The following example is a conservative, progressive plan intended for people who have medical clearance. Sessions are three times per week: two combined HIIT + strength days and one lighter aerobic or active recovery day.

Weeks 1 to 4 — Introduction and adaptation

• Warm-up 8 to 10 minutes: walking or cycling at easy pace plus dynamic mobility.
• HIIT 4 to 6 intervals of 30 to 45 seconds at moderate-hard effort (RPE 6 to 7) with 90 seconds of active recovery. Total interval time 8 to 12 minutes.
• Strength 20 minutes: 2 sets of 8 to 12 repetitions of key exercises (seated row, chest press or push-ups from wall/knee, leg press or squats to chair, overhead press, step-ups). Use manageable resistance.
• Cooldown 5 to 8 minutes light walking and stretching.

Weeks 5 to 8 — Progression

• Increase intervals to 45 to 60 seconds work and 90 seconds recovery. Aim for RPE 7 to 8 during work intervals.
• Strength: progress to 3 sets for major lifts as tolerated and increase resistance gradually while keeping reps 8 to 12.
• Start timing sets and record effort to monitor progress.

Weeks 9 to 12 — Consolidation and conditioning

• Intervals of 60 to 90 seconds work with 90 to 120 seconds recovery, total interval block 12 to 20 minutes.
• Strength: continue progressive overload with safe technique. Include single-leg exercises and core work for balance.
• Optional: add one short, steady-state aerobic session (20 to 30 minutes) at moderate intensity on a separate day.

What to expect and realistic outcomes

With supervised, tailored programs most participants can expect:

• Measurable strength gains within weeks to months.
• Improved functional capacity for daily tasks and mobility.
• Short-term increases in certain immune cell activities after exercise sessions, especially natural killer cell function, which may help immune surveillance.
• Improved mood, sleep, and energy for many people.

Avoid unrealistic expectations: exercise is supportive care, not a cure. Evidence linking exercise to fewer infections or to changes in long-term disease course is still emerging.

Pitfalls, mistakes, and common misconceptions

• Misconception: "More is always better." Excessive intensity or volume without recovery raises injury and illness risk. Progress gradually.
• Skipping medical clearance. Important for people with cardiac history, recent treatment, or severe cytopenias.
• Ignoring symptoms. Stop exercise and seek medical advice for chest pain, new fainting, sudden breathlessness, fevers, or uncontrolled bleeding.
• Using heart rate alone when on certain medications. Use RPE and the talk test if medications blunt heart rate response.
• Assuming exercise replaces vaccines or infection prevention. Exercise can supplement health but vaccines, prophylaxis, and other medical measures remain essential.

Practical tips for getting started

• Get written clearance from oncology or your primary physician before beginning HIIT or heavy resistance work.
• Start in a supervised setting with a physiotherapist, exercise physiologist, or certified trainer experienced with cancer or older adults.
• Keep a training log of session type, duration, RPE, and any symptoms.
• Focus on sleep, nutrition, and hydration—these amplify exercise benefits.
• If neutrophil or platelet counts are low, modify or pause sessions per hematology guidance.

Frequently asked questions

Can exercise improve vaccine responses in people with CLL?

Data are limited. Some studies in other populations show that exercise can enhance vaccine responses, but results in CLL are not definitive. Vaccination remains important and should follow oncology guidance.

Is HIIT safe for older adults with CLL?

When individualized, medically cleared, and supervised, HIIT can be safe and effective for many older adults with CLL. Start conservatively and use RPE and professional supervision as needed.

What if I am undergoing CLL treatment?

Treatment may change blood counts, energy levels, and infection risk. Coordinate with the oncology team. Many people can continue adapted exercise during treatment, but individual plans are essential.

Summary

Structured exercise programs combining tailored HIIT and resistance training offer promising benefits for older adults with CLL. Early clinical work shows improved strength and markers of innate immune activity when programs are supervised and participants are medically cleared. Exercise is not a substitute for medical care, vaccines, or infection prevention, but it can be a powerful part of supportive care to improve resilience, function, and quality of life. Talk to your healthcare team, start with professional guidance, and progress safely.