Immune responses to exercise in children treated for cancer.

BACKGROUND: Children treated for cancer commonly benefit physiologically from moderate aerobic training, but it is less clear if impairment of the immune system secondary to chemotherapy reduces the immunological tolerance of exercise relative to normal children. EXPERIMENTAL
DESIGN: a case series.
SETTING: hospital laboratory. PARTICIPANTS: six children aged 13-14 yr, successfully treated for acute lymphoblastic leukaemia and other types of neoplasms, were compared with 11 normal volunteer children.
INTERVENTIONS: three of the sample underwent 12 weeks training at 70-85% of maximal heart rate; the remaining three provided initial and final test data only. MEASURES: mood state (Piers-Harris test), anthropometric data, maximal oxygen intake, response to 30 min exercise challenges at anaerobic threshold, and standard immune measures (differential count, cytolytic activity, and mitogen-induced lymphocyte proliferation) at rest, during and following submaximal exercise.
RESULTS: A low maximal oxygen intake, excess of body fat, and high anxiety scores all improved with training. Children who were still receiving chemotherapy showed low resting CD3+, CD4+, CD8+, CD19+ and CD25+ counts and reduced PHA-induced proliferation. Acute exercise and training caused further impairment of immune responses, although changes remained insufficient to cause concern for health.
CONCLUSIONS: Exercise therapy is beneficial following treatment of cancer, but should be prescribed individually, with a careful monitoring of immune responses.