A groundbreaking study emerging from the University of Sherbrooke and the Research Centre on Aging in Quebec, Canada, has challenged traditional paradigms regarding exercise and chemotherapy treatment. The research focuses on how strategic timing of aerobic exercise—specifically moderate-to-high-intensity sessions conducted the day before chemotherapy—may influence cancer-related fatigue and physical activity levels in patients undergoing treatment for advanced cancers. Published in the reputable journal Translational Exercise Biomedicine, this pioneering randomized crossover pilot study opens a new frontier in supportive oncology care by highlighting both the safety and potential clinical benefits of pre-chemotherapy exercise interventions.
Cancer-related fatigue is among the most debilitating side effects experienced by individuals receiving chemotherapy. This profound and persistent exhaustion impacts both quality of life and treatment adherence. With conventional wisdom often advising rest and minimal exertion near treatment days, this investigation probes a counterintuitive angle: could a well-timed bout of aerobic exercise actually ameliorate post-chemotherapy fatigue rather than exacerbate it? The study included 12 patients aged 45 to 65 diagnosed with metastatic breast, colorectal, or prostate cancer, all undergoing chemotherapy regimens. By employing a randomized crossover design, each participant engaged in three distinct pre-treatment scenarios—seated rest, moderate continuous aerobic exercise, and high-intensity interval exercise—allowing direct comparison within subjects.
The experimental exercise protocols were meticulously tailored to ensure mechanical work parity across modalities. Moderate continuous aerobic exercise involved 30 minutes at 50% of the participant’s submaximal power, while the high-intensity interval exercise incorporated ten separate 1-minute vigorous intervals with active recovery periods. This design factored in both exercise intensity and volume, key parameters known to modulate physiological stress and recovery responses. Immediately following each pre-chemotherapy condition, participants were closely monitored for five subsequent days to assess fluctuations in fatigue, symptom burden, mood, sleep, and physical activity.
Cancer-related fatigue exhibited a diurnal pattern, with intensities rising toward the evening. Importantly, while patterns of fatigue change over time were consistent across intervention groups, the high-intensity interval exercise condition uniquely demonstrated a statistically significant reduction in perceived fatigue on Day 5 after chemotherapy administration. This delayed beneficial effect suggests that intense aerobic exercise performed before chemotherapy might activate physiological pathways conducive to fatigue attenuation in the days following treatment. Such findings underscore a potentially critical window in which pre-treatment exercise exerts systemic effects that modulate recovery trajectories.
The study also integrated Ecological Momentary Assessment methods to capture real-time symptom fluctuations, enhancing data resolution beyond standard retrospective questionnaires. Additionally, objective accelerometer-based measurements tracked sedentary behavior, light physical activity, and moderate-to-vigorous physical activity during the critical five-day post-treatment period. Interestingly, while cancer-related fatigue demonstrated meaningful variation, no significant changes were observed in physical activity levels or sedentary time across rest or exercise conditions, suggesting that pre-chemotherapy exercise influences fatigue largely independent of subsequent changes in habitual activity.
However, the investigation did note some trade-offs. Nausea severity appeared to increase transiently after high-intensity interval exercise, showing significant elevation on Day 3 post-treatment, and moderate exercise participants reported heightened nausea on Day 5. Meanwhile, mood states and sleep quality metrics remained relatively stable, indicating that these symptoms may be less sensitive to pre-treatment exercise modalities or require larger sample sizes to detect changes. Collectively, these nuanced effects highlight the complex interplay between exercise, chemotherapy toxicity, and symptom management.
Corresponding author Prof. Eléonor Riesco emphasizes the clinical importance of these findings, stressing that engaging in moderate to vigorous aerobic exercise the day before chemotherapy did not worsen fatigue, nausea, or other treatment-related symptoms—a critical reassurance for patients and clinicians alike. Furthermore, the suggestion that high-intensity interval training might mitigate cancer-related fatigue days after chemotherapy opens intriguing possibilities for incorporating tailored exercise prescriptions into standard oncological care paradigms. This proactive approach might not only improve therapeutic tolerance but also enhance patients’ overall well-being and functional capacity.
From a mechanistic standpoint, the potential benefits of pre-chemotherapy exercise could stem from several intertwined physiological processes. Exercise-induced improvements in mitochondrial function, inflammatory modulation, and enhanced muscle perfusion may collectively counteract fatigue pathways exacerbated by cytotoxic chemotherapy. High-intensity intervals, in particular, trigger significant autonomic and metabolic adaptations that could prime the body for improved resilience against treatment-induced stressors. Still, the observed transient increase in nausea after exercise underscores the need to balance intensity and symptom burden in clinical applications.
This study aligns with and reinforces international clinical oncology recommendations, such as those from the European Society for Medical Oncology and the American Society for Clinical Oncology, which advocate physical activity as a non-pharmacological intervention for managing cancer-related fatigue. Yet, the novelty here lies in the identification of the timing of exercise relative to chemotherapy sessions as a modifiable factor with clinical relevance. The researchers highlight that even modest, delayed fatigue reduction without exacerbation of symptoms is a meaningful outcome in metastatic cancer populations, where maintaining functional independence often requires nuanced therapeutic strategies.
Importantly, these findings herald a paradigm shift regarding exercise oncology by suggesting that physical activity may no longer be relegated exclusively to post-treatment rehabilitation or general health promotion but can be strategically integrated into pre-treatment routines. This opens new vistas for multidisciplinary collaboration involving oncologists, exercise physiologists, and supportive care teams to personalize exercise prescriptions and optimize patient outcomes during an otherwise challenging therapeutic phase.
While the study’s pilot design and small cohort size necessitate cautious interpretation, the rigorous crossover methodology and real-time symptom tracking provide robust preliminary data that justify larger clinical trials. Future research should aim to delineate optimal exercise intensities, durations, and timing relative to diverse chemotherapy regimens, incorporate biochemical and molecular correlates of fatigue modulation, and evaluate long-term functional and quality-of-life endpoints.
In sum, this trailblazing investigation from the University of Sherbrooke paves the way toward redefining the role of exercise within cancer care. By demonstrating that moderate-to-high-intensity aerobic exercise performed just before chemotherapy is both safe and potentially beneficial for reducing the fatigue burden in patients with advanced cancer, it offers new hope and actionable strategies to improve survivorship experiences. As the oncology community continues to embrace integrative approaches, exercise prescription tailored to treatment timing may emerge as a key pillar of supportive care, thereby enhancing resilience and empowering patients throughout their cancer journey.
Subject of Research: Effects of aerobic exercise performed the day before chemotherapy on cancer-related fatigue and active behavior in advanced cancer patients
Article Title: Effects of aerobic exercise performed the day before chemotherapy on cancer-related fatigue and active behavior in advanced cancer patients: a randomized crossover pilot study
News Publication Date: 8-Jan-2026
Web References: DOI: 10.1515/teb-2025-0037
Image Credits: Adeline Fontvieille, Hugo Parent-Roberge, Laurence Poirier, Tamàs Fülöp, Michel Pavic, and Eléonor Riesco
Keywords: Chemotherapy, cancer-related fatigue, aerobic exercise, high-intensity interval exercise, moderate continuous exercise, supportive cancer care, physical activity, metastatic cancer, fatigue management
