Body Composition Benefits Diminish One Year After a Resistance Training Regimen in Breast Cancer Patients, Although Improvements in Strength, Balance, and Mobility Persist.

Abstract

Objectives: Resistance training can improve body composition and physical function during and after breast cancer treatment and improve quality of life. It is unclear whether these changes persist once a person is no longer actively enrolled in a structured exercise regimen. Thus, we analyzed participants from the EXERT-BC protocol, assessing an intense exercise regimen in women with breast cancer at one year.

Methods: All the participants were asked to undergo reassessment at one year. Current exercise habits, injuries, changes in medical history, body composition, handgrip strength, functional mobility and balance, and patient-reported quality of life were assessed. Pairwise comparison was performed via the paired t test.

Results: Out of 40 initial participants, 33 returned for reevaluation, with 6 lost to follow-up and 1 with unrelated hospitalization. The median age was 57.8 years, and stage at diagnosis was 1. Weekly exercise was reported by 16 participants (48.5%), with 14 of the 16 following structured resistance training. Between completion of the EXERT-BC and one year follow-up, five women (15.2%) experienced musculoskeletal injuries, which inhibited their ability to exercise. Three women (9%), who were no longer exercising experienced orthopedic injuries requiring medical intervention. The significant reduction in percent body fat, total body fat, excess fat, and increases in muscle mass, resting metabolic rate, and whole-body phase angle dissipated at 1 year. Activity levels and quality of life were no longer significantly improved. However, strength, mobility, and balance remained significantly improved versus pre-exercise measurements, whether a participant was still engaged in exercise or not.

Conclusions: After a 3-month dose-escalated resistance training regimen, exercise compliance was poor at one year. The anthropomorphic benefits of the regimen regressed by one year; however, the improvements in strength, balance, and mobility persisted.