Why Exercise Matters During and After Cancer Treatment

When facing cancer—whether you're newly diagnosed, in treatment, or navigating life after—exercise may feel like the last thing on your mind. You may be thinking: “I’m too tired,” or “I’m not strong enough.” “I never liked exercise, even before my diagnosis.” These are valid concerns that I have heard from patients in my 20 years of medical practice. But here's the good news: research has shown that moving your body in safe, appropriate ways can actually help you feel better, recover faster, and even prevent cancer from coming back.

The Science: How Exercise Helps Your Body Fight Cancer

Exercise does more than strengthen your muscles or help manage weight. For people with cancer, it plays a key role in:

• Reducing fatigue: One of the most common side effects of cancer and its treatments is fatigue. Ironically, gentle and regular physical activity can be one of the most effective ways to reduce it ¹.
• Boosting mood and mental health: Physical activity stimulates chemicals (such as endorphin) in the brain that help you feel better emotionally, decreasing symptoms of anxiety and depression ².
• Preserving physical function: Exercise helps maintain balance, strength, flexibility, and stamina—important for staying independent and preventing falls. This is especially key during cancer treatment as these functions may decline at an accelerated pace ³.
• Enhancing treatment tolerance: Staying active may help you complete your treatment on schedule, with fewer dose reductions or delays ⁴.
• Lowering mortality risk: For certain cancers—like breast, colorectal, and prostate—studies suggest that regular exercise is linked to a lower risk of recurrence and longer survival ⁵. 

What Does the Research Say?

Over the past decade, dozens of clinical studies and reviews have shown that exercise is both safe and beneficial for people living with and beyond cancer. In fact, in 2019, leading experts—including the American College of Sports Medicine (ACSM), the American Cancer Society (ACS), and more—released updated guidelines recommending regular physical activity during cancer treatment and recovery ⁶.

More recently, in 2022, the American Society of Clinical Oncology (ASCO) formally endorsed these exercise guidelines. ASCO's endorsement sends a clear message: exercise should be a standard part of cancer care ⁷.

In 2025, the Challenge trial (N=889) published in the New England Journal of Medicine found that structured exercise program led to reduced cancer recurrence and improved overall survival for patients with colon cancer ⁸.

What Do the Guidelines Recommend?

Here’s a simplified version of what the current clinical guidelines suggest:

• Aerobic activity: Aim for about 150 minutes of moderate-intensity aerobic exercise per week (like brisk walking, swimming, or cycling), or 75 minutes of vigorous activity.
• Strength training: Include strength-building exercises (like light weights or resistance bands) at least two days a week.
• Flexibility and balance: Activities like stretching, yoga, or tai chi can support flexibility, mobility and reduce fall risk.

Of course, these are general recommendations—not one-size-fits-all, particularly among patients who are undergoing treatment or had recent surgery. The most important step is to start where you are.  Our Greatly Health Integrative Care team is here to develop an exercise plan that matches your energy, abilities, and goals.

But What If I’m Too Tired or Sick?

It’s okay. Movement doesn’t have to mean running a marathon. Some days, after chemotherapy, a short walk down the hall, several intentional deep breathing exercises, or a few minutes of chair yoga or stretching is enough. The key is consistency over intensity.

Start small. Celebrate what your body can do. And remember— Any movement is better than none.

A Note to Caregivers

If you’re caring for someone with cancer, your encouragement and support can make a big difference. Caregiving can also be physically exhausting and emotionally distressing, you might even consider joining them in an activity—it can be a powerful way to bond, boost spirits, and build healthy habits together.

Final Thoughts: Exercise is Medicine—Even During Cancer

Exercise isn’t about pushing yourself beyond limits. It’s about reclaiming strength, improving quality of life, and taking control where you can. With guidance from your oncology team, physical therapists, or our Greatly Health team of instructors, it can become a safe, empowering, and healing part of your journey.

You’re not just surviving—you’re moving toward thriving.