Exercise and Cancer Outcomes
Movement is Medicine: the Science of Exercise and Cancer Risk Reduction
Exercise is one of the most powerful, yet overlooked, tools in cancer care. It can help prevent cancer, improve treatment response, and reduce the risk of recurrence. But despite overwhelming evidence, exercise is still vastly underutilized in oncology.
I see this disconnect every day in my clinic. Patients going through treatment often ask, “Should I be resting more?” “Is it safe to exercise?” “What should I be doing?” Many assume that because cancer and its treatments can stress the body, exercise might do more harm than good. They’re afraid of pushing too hard, when in reality, movement is one of the best things they can do.
At the same time, most oncologists receive little to no formal training in exercise oncology — the science of how movement affects cancer outcomes. This means that when patients ask about exercise, they often get well-meaning but vague advice like, “Try to stay active” or “Get your steps in.” While these recommendations aren’t wrong, they’re not specific enough to make a real impact.
But here’s what the research tells us:
Exercise is medicine. It’s not just about feeling better or maintaining fitness—it can enhance treatment response, lower recurrence risk, and improve survival.
It’s never too early or too late to start. Whether you’re newly diagnosed, in active treatment, or years into survivorship, the right kind of exercise can help.
One-size-fits-all advice isn’t enough. The best exercise routine is tailored to your individual needs, energy levels, and treatment stage.
So, let’s get specific. This article will break down exactly what kind of exercise works best, why it matters, and how to make it work for you. Whether you’re a patient, a caregiver, or just looking to optimize your health, movement should be a part of your plan. Because when it comes to fighting cancer, exercise isn’t optional—it’s essential.
How Exercise Lowers Cancer Risk: Strengthening Your Body’s Defense System
Cancer isn’t just a disease—it’s a breakdown in the body's ability to regulate cell growth and maintain a healthy internal environment. Fortunately, exercise helps build a precision defense system, strengthening the body’s natural ability to detect and eliminate threats. Decades of research show that physical activity reduces the risk of multiple cancers, including breast, colon, prostate, and endometrial cancer.1
Here’s how exercise fortifies your body’s defenses and keeps cancer in check.
1. Chronic Inflammation: Exercise Clears the Haze
Inflammation plays a key role in tumor development. Persistent low-grade inflammation creates a biological haze, weakening immune surveillance and creating an environment that promotes cancer growth. Exercise helps counteract this effect by lowering levels of pro-inflammatory mediators, including:
Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-α): When these inflammatory markers stay elevated for too long, they can create an environment where precancerous cells grow and survive more easily. Exercise helps bring them back to healthy levels, reducing inflammation and supporting a stronger immune system.
C-reactive protein (CRP): Elevated CRP is a biomarker of systemic inflammation linked to cancer progression. Exercise reduces CRP, decreasing the overall inflammatory burden.2
By restoring immune visibility and reducing inflammatory signaling, exercise creates an environment in which malignant cells are more readily recognized and eliminated.
2. Exercise Regulates Hormonal Pathways to Limit Cancer Growth
Hormonal imbalances contribute to tumor growth, particularly in hormone-sensitive cancers such as breast, endometrial, and prostate cancer. Exercise exerts endocrine-modulating effects, reducing excess growth signals that promote cancer:
Breast & Endometrial Cancer: Physical activity increases sex hormone-binding globulin (SHBG), reducing bioavailable estrogen—a key driver of hormone-dependent tumor growth.34
Prostate Cancer: Exercise helps regulate androgen levels, maintaining a balance that limits excessive stimulation of prostate cells.
Through these mechanisms, exercise interrupts hormonal signaling pathways that support tumor growth.
3. Optimizes Metabolic Function to Restrict Cancer’s Energy Supply
Cancer cells have unique metabolic needs, thriving in environments rich in insulin, glucose, and growth factors. Exercise helps counteract these advantages by:
Improving insulin sensitivity: High insulin and insulin-like growth factor-1 (IGF-1) levels are linked to increased cancer risk. Exercise lowers these levels, cutting off key growth signals for tumors.
Boosting mitochondrial function: Physical activity enhances cellular energy metabolism, making it harder for cancer cells to rely on anaerobic glycolysis (the Warburg effect) for survival.
Reducing fat-driven inflammation: Visceral fat releases inflammatory signals that support tumor growth. Exercise decreases visceral fat, reducing this harmful influence5
By altering systemic metabolism, exercise creates an inhospitable environment for cancer progression.
4. Enhances Immune Surveillance to Detect and Eliminate Malignant Cells
The immune system helps detect and destroy abnormal cells before they turn into cancer. Exercise strengthens this defense by:
Activating Natural Killer (NK) Cells: These cells are the body's first line of defense against cancer. Exercise boosts their ability to find and destroy tumor cells.6
Cytotoxic T Cells: These adaptive immune cells recognize and attack abnormal cells. Exercise enhances their activation and infiltration into tissues, improving surveillance.
Through these effects, exercise strengthens the body's natural ability to identify and eliminate precancerous and malignant cells.
5. Reprograms the Tumor Microenvironment
Tumors do not grow in isolation, instead, they manipulate their surrounding environment to suppress immune responses and resist treatment. Exercise counteracts these adaptations by:
Increasing oxygen delivery: Tumor hypoxia promotes aggressive growth and resistance to therapy. Exercise improves vascular function, increasing oxygenation and making tumors more susceptible to immune attack and treatments.7
Lowering immune suppression: Tumors release signals that weaken the immune system. Exercise helps counteract this, allowing immune cells to better detect and attack cancer cells.
By modifying the tumor microenvironment, exercise reduces the likelihood of malignant progression and improves the efficacy of existing cancer therapies.
"If exercise were a drug, it would be the most effective cancer prevention and treatment support available—yet it remains vastly underutilized."
Exercise is emerging as a key tool in cancer care, offering benefits that go beyond general well-being. Research shows that regular physical activity during treatment can improve outcomes, reduce side effects, and support overall health. While cancer treatments like chemotherapy, radiation, and immunotherapy are critical in fighting the disease, they can also take a toll on the body. Exercise helps counteract these effects in multiple ways.
How Exercise Supports Patients During Cancer Treatment
Improved response to immunotherapy: Exercise stimulates the immune system. Some studies suggest that this may help improve the effectiveness of checkpoint inhibitors, a class of immunotherapy drugs that rely on immune activation to fight cancer.8
Reduced cancer-related fatigue: Fatigue is one of the most common and debilitating side effects of cancer treatment. Multiple randomized trials have shown that even moderate exercise can significantly reduce fatigue, improve energy levels, and enhance overall well-being.9
Preserved muscle mass and metabolism: Cancer-related muscle loss, known as sarcopenia, can impact treatment tolerance and overall prognosis. Resistance training and aerobic exercise help maintain muscle mass, prevent excessive weight loss, and support metabolic health.10
Better cognitive function and mental clarity: Many cancer patients experience "chemo brain," a term used to describe cognitive issues like brain fog, memory problems, and difficulty concentrating. Physical activity has been shown to support brain health, potentially reducing these cognitive side effects.11
In addition to these benefits, studies suggest that patients who remain active tolerate chemotherapy and radiation better, experience fewer complications, and recover more quickly after treatment.
Exercise Lowers Cancer Recurrence Risk
For cancer survivors, staying active is one of the most effective ways to reduce the risk of recurrence. Research consistently shows that regular physical activity lowers the likelihood of cancer returning and improves overall survival. This impact is seen across multiple cancer types, including breast, colorectal, and prostate cancer.
How Much Does Exercise Reduce Recurrence Risk?
The effect of exercise on cancer recurrence is not just theoretical — it’s backed by strong evidence. Several large cohort studies and meta-analyses have demonstrated significant reductions in recurrence rates and cancer-specific mortality among survivors who engage in regular physical activity.
Breast Cancer: Studies show that breast cancer survivors who engage in regular exercise experience a 40-50% lower relative risk of recurrence compared to those who are inactive. A large meta-analysis published in JAMA Oncology found that moderate physical activity, such as brisk walking for 150 minutes per week, is associated with significantly improved survival rates12
Colorectal Cancer: Regular physical activity is associated with a 30-40% lower relative risk of recurrence in colorectal cancer survivors. A prospective study in the Journal of Clinical Oncology followed stage III colorectal cancer patients and found that those engaging in at least 150 minutes of moderate-intensity exercise per week had significantly improved disease-free survival compared to sedentary patients.13
Prostate Cancer: Exercise has also been linked to a 30% relative reduction in cancer-specific mortality among men with prostate cancer. A Harvard study following thousands of prostate cancer survivors found that those who engaged in at least three hours of vigorous exercise per week had lower mortality rates and slower disease progression.14
These are real, tangible reductions in the likelihood of cancer returning, reinforcing the idea that exercise is not just beneficial—it’s a crucial part of survivorship care.
Getting Started: First Steps Toward Better Health
When I talk to patients about exercise, I always emphasize you don’t have to figure this out alone. The key is to start where you are and build from there. Small, consistent steps will create lasting results. If you’re ready to make movement a part of your routine, here are three things I highly recommend:
1. Consider a Personal Trainer (If It’s an Option for You)
I can’t tell you how many times I’ve seen patients sign up for a gym, full of good intentions, only to stop going because they feel lost, intimidated, or unsure of what to do. This is completely understandable. Walking into a gym without a plan can feel overwhelming, and that’s where a good personal trainer can make all the difference.
They provide structure and accountability. Having guidance makes it much easier to stay consistent.
They help you feel confident. No more wandering around the gym, unsure of what to do.
They create a plan that works for you. A trainer can tailor workouts to your energy levels, mobility, and medical history.
I know that cost and access can be real concerns, and a trainer isn’t necessary for everyone. But if it’s an option for you, even for just a few sessions, it can be incredibly valuable. Many patients find that investing in a few guided sessions helps them feel more comfortable and confident continuing on their own.
And the good news? You may have more options than you think. Many cancer centers, oncology rehab programs, and YMCAs (through the LiveStrong program) offer free or low-cost resources to connect survivors with trainers who understand their unique needs.
At the end of the day, the goal is to find a way to move that feels safe, sustainable, and effective for you. If you’ve struggled to stay consistent, having the right support could make all the difference.
2. Learn About and Consider Zone 2 Training
When I talk to patients about exercise, Zone 2 training is one of the first things I recommend. It’s low-impact, sustainable, and incredibly effective—the kind of movement that improves your health without leaving you exhausted.
Zone 2 is that sweet spot where your heart rate is elevated, but you can still hold a conversation. You’re working, but not pushing too hard—making it ideal for building endurance, improving metabolism, and supporting recovery.
And it’s not just for cancer survivors. Elite athletes, longevity researchers, and metabolic health experts all incorporate Zone 2 training into their routines because of its ability to enhance fat metabolism, improve mitochondrial function, and build long-term aerobic fitness.
How Much?
150 minutes per week (or 21 minutes per day) is the gold standard.
But if that feels like too much, start where you can—even 5-10 minutes a day makes a difference.
What Counts as Zone 2?
Brisk walking – The easiest and most accessible way to get started.
Cycling at a comfortable pace – Great for joint-friendly endurance.
Swimming – A full-body, low-impact option.
Elliptical or rowing machine – Good choices for controlled, steady movement.
If you’re not sure where to start, just walk. A short walk after meals, a stroll with a friend, or a little extra movement throughout the day adds up quickly.
The key? Find something you enjoy and do it consistently. Small efforts over time lead to big results.
3. Add Resistance Training
Aerobic exercise is critical, but strength training is just as important—especially as we age or recover from illness. It’s what keeps you strong, mobile, and independent.
Here’s why it matters:
Prevents muscle loss (sarcopenia) – Cancer treatment, aging, and inactivity all cause muscle breakdown. Strength training reverses that decline and keeps you strong.
Improves bone health – Weight-bearing exercises increase bone density and help prevent osteoporosis.
Boosts metabolism – More muscle means better blood sugar control, weight regulation, and energy levels.
Supports everyday function – Whether it’s carrying groceries, climbing stairs, or playing with your grandkids, strength training keeps you capable.
How much?
Aim for twice per week
Full-body focus—legs, arms, core, back
What counts as strength training?
Bodyweight exercises – Squats, lunges, push-ups
Resistance bands – Gentle but effective
Dumbbells or kettlebells – Strengthens muscles and bones
Yoga or Pilates – Builds functional strength and flexibility
And yes, strength training counts toward your 21-minute goal—so if you’re lifting weights twice a week, you’re already on your way.
Personalizing the Plan
Once I understand where my patients are starting, we create a plan that fits their lifestyle. If they’re already active, we fine-tune their routine to maximize benefits. If they’re new to exercise, we find simple, realistic ways to start.
If you’re thinking, "I don’t have time," or "I don’t know where to begin," that’s okay. Start small and build from there. Take a 5-minute walk. Do a few squats. Just move more today than you did yesterday.
And before jumping into anything new, talk to your doctor. If you have specific concerns such as neuropathy, bone metastases, or joint paint your oncologist or physical therapist can help tailor an approach that works for you.
Bottom line: movement is medicine. It doesn’t have to be complicated. Find something you enjoy, make it a habit, and keep moving. Your future self will thank you.
For oncology providers seeking to incorporate exercise into patient care, the American College of Sports Medicine (ACSM) offers a comprehensive, evidence-based guide detailing physical activity recommendations tailored for cancer patients. This resource provides practical guidelines to help you prescribe safe and effective exercise regimens.
You can download the ACSM's "Guidelines for Exercise and Cancer" PDF here:
Integrating these guidelines into your practice can significantly enhance patient outcomes by addressing specific symptoms and side effects associated with cancer and its treatments.
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Excellent directives. I’ve been on the cancer train for 15 years. Metastatic 5 years ago. My job is to do self care while the onco’s is to treat the disease. I forest hike up and down the mountain trails almost daily. When I worked, I would push off at dark and was at work by 9. A daily hike is restorative. So thankful I can do that. Thank you for this page of your collective wisdom and encouragement.
I loved this piece, Daniel. This article makes it clear that a personalized exercise program would be prudent to include in treating cancer holistically. I am glad you are shedding light on this subject. Many people (including myself) didn't know this before.