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Dr. Andrea Sitlinger on High-Intensity Interval Training for Older Adults with Chronic Lymphocytic Leukemia (CLL)

In science and medicine, information is constantly changing and may become out-of-date as new data emerge. All articles and interviews are informational only, should never be considered medical advice, and should never be acted on without review with your health care team.

Patients with chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are immunocompromised, meaning that their immune system does not work as well as in healthy people. This is not surprising given that CLL and SLL are cancers of B cells, which are important immune cells responsible for producing antibodies that help our body fight infections. However, CLL and SLL don’t just affect B cells, as there are other components of the immune system that are also not working normally. One of the big questions for patients is whether there is anything they can do to boost their immune system?

Our own Dr. Brian Koffman spoke with Dr. Andrea Sitlinger, Assistant Professor of Medicine and hematologist at Duke Cancer Center in Durham, NC. They talked about the results of a pilot study on high-intensity interval training for older adults with CLL or SLL.


  • Various types of exercise can affect your immune system and, in healthy older adults, higher physical activity and physical fitness is associated with better immune function.
  • In lymphoma patients, increasing physical activity levels and physical fitness are associated with improvements in therapy-related side effects, physical functioning, and quality of life.
  • High-intensity interval training is short periods of very demanding physical activity alternated with less intense recovery periods.
  • For this pilot study, participants were assigned to high-intensity interval training or the control group, who were informed to continue their daily activities and not participate in a structured exercise program.
  • Participants were screened for cardiorespiratory fitness prior to enrolling in the study to ensure that they could exercise safely at high intensities.
  • The exercise program consisted of both aerobic exercise on a treadmill and resistance training with weights. High-intensity intervals were between 60 and 90 seconds followed by active-recovery intervals of a similar duration.
  • Exercise sessions were conducted three times per week for 12 weeks and lasted about 1 hour.
  • Sixteen participants with stable, treatment-naïve CLL completed the 12-week study. There were an equal number of men and women participants, and the average age was 65 years.
  • Six participants were assigned to the control group based on living too far (>35 miles) from the clinical testing site to travel 3 times per week for exercise sessions.
  • Ten participants were assigned to high-intensity interval training, and 100% of these participants were able to complete >75% of their prescribed exercise minutes.
  • The high-intensity interval training group had significant increases in strength in their leg muscles and upper body muscles compared to the control group. However, overall cardiorespiratory fitness did not change.
  • The high-intensity interval training group had significant increases in the number of natural killer cells in their blood compared to the control group. These natural killer cells also had increased killing ability when studied in a test tube.
  • Natural killer cells are a type of immune cell that can kill cancer cells or cells infected with a virus.


While this was a small pilot study, it does provide encouraging results. Patients with CLL were able to safely engage in a regular exercise program which improved their health, both in terms of muscle strength and immune function. Larger studies would be needed to confirm these findings in a broader swath of patients. Taking care of your body and mind is important, and exercise can potentially help. Check with your doctor before starting an exercise program. If you are interested in all the details of this study, the full scientific paper can be found here.

Please enjoy this brief interview with Dr. Sitlinger.

Take care of yourself first.

Ann Liu, PhD