This is where the science gets really interesting, and where many people are most surprised. Far from being something to avoid during chemotherapy, radiation, or hormonal therapy, well-prescribed exercise actively helps people get through treatment.

Here's some of what the research has shown:

Cancer-related fatigue. Surprisingly, the single most effective intervention for the deep, heavy fatigue that comes with cancer treatment is movement. Combined aerobic and resistance training, prescribed at moderate intensity, consistently reduces fatigue more than rest alone.

Mood and mental health. Treatment is emotionally relentless. Studies show that supervised exercise programs significantly reduce both anxiety and depressive symptoms in people undergoing cancer treatment, with combined aerobic and resistance training producing the strongest effects.

Heart protection. Some cancer therapies, particularly certain chemotherapies, targeted drugs, and chest radiation, can place significant stress on the heart. Exercise during treatment has been shown to protect cardiorespiratory fitness, with one trial showing the exercise group actually improved their fitness during chemotherapy while the usual-care group declined. Beyond fitness, exercise meaningfully reduces markers of heart muscle injury during treatment.

Joint pain from hormone therapy. Women on aromatase inhibitors for breast cancer often experience joint pain so significant that up to one in five will stop taking their medication within the first year, which directly affects survival. A landmark 12-month trial found that combined aerobic and strength training reduced worst joint pain by 29%, compared to a 3% increase in those who didn't exercise. That's not just comfort. That's helping people stay on a life-saving treatment.

Bone health during hormone therapy. Men on androgen deprivation therapy for prostate cancer can lose bone density rapidly. Structured resistance and impact training has been shown to preserve bone at key sites in the spine and reduce the risk of falls. This is critical when both muscle mass and bone strength are under attack from treatment.

This is the chapter that often gets the least attention but may matter the most. Treatment ends, scans come back clear, and the question becomes: what now?

The evidence here is striking. Among survivors of breast, colorectal, and prostate cancer, regular post-diagnosis exercise, equivalent to about 150 minutes of brisk walking per week, is associated with roughly a 45% lower risk of disease recurrence. Long-term studies have shown that breast cancer survivors who exercised consistently had a 48% lower risk of dying from any cause, and a 38% lower risk of dying from breast cancer specifically, compared to those who remained inactive. In colorectal cancer survivors, the numbers are similar.

One eight-year clinical trial found that breast cancer patients randomised to a structured exercise program had a 37% reduction in overall mortality compared to those who received only health education.

These aren't small effects. They're the kind of effects that would make headline news if they came from a pill.

The "how" of all this is worth understanding, because it changes how seriously we take it. Exercise isn't just burning calories or building muscle. At the cellular level, it appears to actively shift the internal environment of the body in ways that are unfavourable to cancer.

Movement improves blood flow into tissues, which means better oxygen delivery and better immune cell access. It reduces chronic, low-grade inflammation. It regulates hormones and insulin. It activates muscle to release signalling molecules, called myokines, that communicate with the immune system and other organs. And it stimulates the muscle-building pathways that cancer treatments often suppress, helping protect against the muscle wasting that makes recovery so much harder.

This is why we now talk about exercise as a genuine therapy, not just a lifestyle factor.

If there's one shift we want to encourage, it's this: stop thinking of exercise as something separate from cancer care. It belongs inside the treatment plan, alongside the oncology team, the surgeon, the medications. The evidence is now strong enough that not offering exercise support to people with cancer is starting to look like a gap in care.

For people currently going through treatment, this means there's something tangible you can do, something that, week by week, has been shown to make the journey more manageable and the outcomes better. For survivors, it means the recovery period is genuinely an opportunity, not just an endurance test. And for everyone else, it's a reminder that the daily choice to move is doing more than we tend to give it credit for.

If you're a current REPS Movement member: if you, or someone close to you, is navigating cancer or recovery from it, talk to your Exercise Physiologist about how your program can be adjusted to support that journey, whether that's protecting bone density, managing fatigue, preserving cardiovascular fitness, or simply staying connected to movement through a difficult season.

If it's been a while since you've been in: we know life, and health, sometimes takes you away from the gym for long stretches. Cancer treatment is one of those stretches where many people quietly disconnect from movement entirely. If that's where you are, please know there's no need to come back at the level you left. We'll meet you where you are now, and we'll build from there.

If you're new to REPS Movement: Exercise Physiology is a regulated allied health profession, and our team is trained to work safely and effectively with people during and after cancer treatment. We work across Medicare CDM, My Aged Care, NDIS, workers' compensation, and private funding streams. If you'd like to talk about what tailored support could look like, for yourself or someone you care about, we'd welcome a conversation.

Movement won't undo a diagnosis. But the evidence is now clear: it changes what's possible from that point forward. And that's a powerful thing to hold onto.