Has treatment for colorectal cancer left you with a weak immune system? This can fix it

Physical activity is an important part of recovery after colorectal cancer treatment. Even something as simple as brisk walking can help you slowly rebuild your strength and stamina (but you need more than just that).

Colorectal cancer treatment is no joke. After surgery, chemotherapy, or radiation, it often takes a long time for your energy and strength to return. Fatigue and low stamina can continue even after treatment has finished. Even when your follow-up scans look reassuring, you can still wonder how well your body is recovering.

In the study I have for you today, scientists studied 60 people who had completed treatment for stage I, II, or III colorectal cancer and found that a 12-week aerobic exercise program improved certain immune cells and lowered chronic inflammation!

What did the exercise involve?

Aerobic exercise is sustained movement that makes your heart and lungs work harder.

The participants were around 60 years old on average. Everyone had undergone surgery, and some had also received chemotherapy or radiation. One group followed an exercise program, while the other continued their usual routine.

The exercise was done at home, using a treadmill and a heart-rate monitor. Sessions included a 5 minute warm-up, 30 to 60 minutes of sustained walking at a set effort, and a 5 minute cool-down. The pace was chosen to raise the heart rate and keep participants working at a moderate intensity.

They built up their exercise time gradually over the first four weeks until they reached 150 minutes per week. The emphasis was on a planned routine with enough effort to challenge the body and enough consistency to repeat it across the weeks.

Blood samples taken before and after the program revealed 2 changes worth knowing about.

Exercise changed cells that help your body watch for cancer

Your immune system contains natural killer cells. Their job includes recognizing and destroying abnormal cells, including cancer cells and cells infected with viruses. They form part of your body’s defenses against cells that should not be there.

After 12 weeks, two types of natural killer cells made up a larger share of these cells in the exercise group than in the group that kept their usual routine. These types have features linked to being ready to recognize and respond to abnormal cells.

The change is encouraging because these cells form part of your body’s defenses against cancer. Your immune system can respond to the exercise you do after treatment. That gives your workouts a purpose beyond rebuilding fitness.

A blood marker linked to persistent inflammation fell

Inflammation helps your body fight infections and repair injuries. When it continues for a long time, however, it can interfere with immune cells doing their job. Constant activation can leave some of those cells exhausted and less effective at responding to threats.

The exercise group had a greater drop in a blood marker linked to this ongoing immune activity than the group that continued their usual routine. In plain language, one sign of persistent strain on the immune system was lower after regular exercise.

This is encouraging because your body’s defenses need to respond to threats without being worn down by constant activation. For someone recovering from colorectal cancer, it is another reason to give exercise a proper place in the week.

The blood samples were taken while participants were resting, after 24 hours without structured exercise. The changes were still present between workouts, when the body was no longer doing the exercise itself.

These changes developed over weeks of repeated exercise. That gives consistency a clear purpose. You may notice progress when climbing stairs or carrying shopping becomes easier, while changes in your immune cells remain invisible. Keep showing up for the routine, even when progress feels gradual.

Walk briskly every day, but also make time for exercise

Everyday walking is physical activity. Keep doing it alongside your dedicated exercise sessions. A slow walk to the shops or an occasional stroll should not be the whole of your plan.

When you go for a walk, pick up your pace. Walk with purpose, so your breathing becomes noticeably faster and your heart works harder. Make that a daily habit. If you are heading somewhere on foot, use the opportunity to move briskly instead of ambling along.

Then prioritize time for planned exercise. Give each session a clear start and finish, and sustain an effort that makes you work. You should feel your breathing and heart rate increase. Build the duration as your stamina improves.

The treadmill sessions described above had a set duration and an effort target. Bring that same purpose to your own workouts. Put them in your calendar, track how much you complete, and gradually increase what you can do.

Work toward 150 minutes of aerobic exercise each week. Thirty minutes on five days is one way to arrange it. If that feels like a big jump, begin with shorter sessions and build up the time. Give yourself a few minutes of easier movement at the beginning and end of each session.

Do not stop walking because you exercised that morning. Keep moving throughout the rest of the day. Equally, do not let your everyday steps become an excuse to skip your planned exercise. Both deserve a place in your routine.

Recovery continues after treatment finishes. Choose your exercise days, make room for a brisk daily walk, and keep building on what you can do.

If you want evidence-based nutrition and lifestyle strategies for colorectal cancer, subscribe to my newsletter for practical weekly guidance. If you want a plan built around your treatment history, medications, diet, exercise, symptoms, and individual goals, my 1-to-1 coaching can help you build a strategy that fits your needs.