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Short workouts may improve the effectiveness of some cancer treatments
Last reviewed: 02.07.2025
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A new study by researchers at the Universities of Birmingham and Bath in the UK has found that intense exercise may improve the effectiveness of rituximab therapy, an antibody often used to treat chronic lymphocytic leukemia (CLL). The findings were published in the journal Brain, Behavior, and Immunity.
Description of the study
The study involved 20 people with chronic lymphocytic leukemia who had not previously received any cancer treatment. As part of the study, the participants cycled for 20 to 30 minutes at moderate to vigorous intensity.
Key findings
The researchers found that this type of exercise increased the number of cancer-fighting immune cells, or natural killer cells, by 254%. When combined with rituximab, which binds to a protein on cancer cells, helping natural killer cells identify and destroy them, the cancer-fighting cells were twice as effective in blood samples taken immediately after the workout.
"This study shows for the first time that a single bout of intense cycling training improves rituximab-mediated ADCC [antibody-dependent cellular cytotoxicity] against autologous chronic lymphocytic leukemia cells ex vivo," the authors write.
Experts' opinion
Dr. Katherine S. Diefenbach, director of the Clinical Lymphoma Program at NYU Langone Health's Perlmutter Cancer Center, who was not involved in the study, said the results are interesting but questions remain because of the small sample size.
"This is a small pilot study of 20 patients in a controlled setting - with limited exercise in a prescribed form - with intriguing biological findings about NK cell activation and rituximab-induced cell killing in CLL," she explained.
"However, these data need to be confirmed in larger studies with a more heterogeneous patient population," Diefenbach cautioned. "It is also unclear how this finding affected clinical outcome or whether it had any implications for response to therapy or disease stability."
Dr. Wael Harb, a board-certified hematologist and oncologist at MemorialCare Cancer Center in Orange County, California, also noted that it's difficult to draw broad conclusions from the study.
"Patients who are able to do intense exercise may have different immunity compared to those who are not. How can we generalize these findings to others given the exercise capacity and sample size?" asked Dr. Harb, adding that because the study relies on ex vivo blood samples, it is difficult to determine what is happening inside the body.
"The most important thing is, how does it affect outcome, right? We need to have long-term results to see, does it really affect response to treatment, remission of leukemia? We would need a more structured study to find out and randomize patients to different regimens with the same treatment - rituximab - or rituximab-containing treatments and add to that different exercise programs," he added.
The Effect of Exercise on Cancer
Although many cancer treatments, especially chemotherapy or surgery, can cause severe fatigue that prevents physical activity, there is growing evidence that exercise can stimulate immune cells.
Dr. Harb explained that physical activity is well documented as a way to boost the body's immune system to fight cancer cells. He cited several studies in recent years that have looked at the effects of short-term, intense exercise and more regular activity patterns.
"We recommend being active and exercising - we believe there is a lot of evidence that exercise during cancer treatment can help the immune system, and now more than ever we understand the role of the immune system in fighting cancer," he said of doctors' recommendations.
"In fact, many of the new cancer treatments are based on immunotherapy, which helps activate the immune system to fight cancer," Harb added, although he also sounded a note of caution about exercise as an adjunct to cancer therapy.
"Intensive exercise is a little more difficult. It depends on the person's ability to exercise, their age, any underlying medical conditions that make it more difficult. So there can be practical issues when we talk about intensive exercise; it limits patient participation," he noted.