Exercising during radiation treatment is scientifically supported and generally safe, provided the activity is modified and occurs with medical clearance. Radiation therapy uses high-energy rays to damage and destroy cancer cells or shrink tumors. During this targeted treatment, physical activity is recommended by major medical organizations as a supportive therapy. The goal is to remain as active as possible, requiring an individualized approach and the direct approval of your oncology care team before beginning any new routine.
Physiological Rationale for Exercise During Treatment
Movement during active treatment counteracts the systemic stress placed on the body by the disease and the therapy itself. A significant benefit is preserving lean muscle mass, which is often diminished by cancer-related cachexia, a wasting syndrome linked to poorer outcomes. Engaging in resistance training helps maintain muscle strength and functional capacity, improving the ability to perform daily tasks despite treatment side effects.
Physical activity also supports a robust immune response. Exercise increases the circulation of immune cells, such as T cells and Natural Killer (NK) cells, which are the body’s natural defenses against cancer. This boost in immune cell activity may help the body better tolerate and respond to the treatment. Furthermore, exercise improves overall circulation and promotes angiogenesis, which may enhance the delivery of oxygen and anti-cancer agents to the tumor site.
Addressing Common Radiation Side Effects Through Movement
The most common limiting factor during and after radiation is Cancer-Related Fatigue (CRF), a persistent exhaustion not relieved by rest. Research demonstrates that exercise is the most effective non-pharmacological strategy for managing this fatigue. Moderate-intensity aerobic activity, such as brisk walking or cycling, is recommended to improve energy levels and overall quality of life.
Exercise also helps mitigate localized side effects near the treatment area, particularly the risk of long-term tissue changes. Radiation can cause fibrosis, where healthy tissue becomes tight and scarred, severely limiting range of motion. Performing regular stretching and flexibility exercises is important for maintaining mobility, especially after radiation to areas like the chest or neck.
The skin at the treatment site may become red, dry, or irritated, requiring modification of activities to prevent friction or infection. Care must be taken to avoid exercises where clothing rubs against the compromised skin, such as certain upper-body resistance movements. Activities involving water immersion, like swimming, should also be avoided if the skin is broken or highly irritated.
Developing a Safe and Personalized Exercise Plan
A safe exercise plan during radiation must be highly individualized, considering the type of cancer, treatment schedule, and current fitness level. The foundation should include both aerobic exercise and light resistance training. Walking is an excellent, low-impact aerobic choice, and resistance can be introduced using bodyweight exercises like chair stands or light resistance bands.
Monitoring workout intensity should rely on your Rate of Perceived Exertion (RPE) rather than strict heart rate metrics. Moderate intensity is defined as a pace where you can comfortably talk but cannot sing. Start with short, manageable sessions, such as three 10-minute bouts of activity spread throughout the day, and increase the duration only as tolerated.
The plan requires constant modification, especially on days when fatigue is higher or following a treatment session. Listening to your body is paramount, meaning duration or intensity must be reduced if energy levels are low. Working with an oncology-focused physical therapist or exercise physiologist ensures the program safely addresses any specific physical limitations or needs.
It is important to recognize specific physical warning signs that indicate exercise should be stopped immediately and medical attention sought. These “red flags” include sudden chest pain, unexpected shortness of breath, sudden dizziness or lightheadedness, or a fever. Safety is always the priority, and any new or severe symptom should be discussed promptly with the oncology care team.