Can Exercise Help Patients With Locally Advanced Rectal Cancer During Cancer Treatment? A Patient-Friendly Review of Research

Table of Contents

• Key Points
• Understanding Locally Advanced Rectal Cancer and Its Treatment
• Why Exercise Is Being Studied as a Supportive Treatment
• A Key Difference: Rectal Cancer vs. Colon Cancer Treatment
• How This Research Review Was Conducted
• Key Findings: Is Exercise Feasible During Cancer Treatment?
• Safety: Exercise Was Well Tolerated
• Functional and Fitness Improvements
• What Helps Patients Stick With Exercise
• Emerging Evidence: Exercise and Tumour Response
• What This Means for Patients
• Limitations of This Review
• Recommendations for Patients
• Frequently Asked Questions
• Source Information

Key Points

• Across 16 reviewed studies, no serious adverse events from exercise were reported, and exercise did not interrupt chemotherapy or radiation treatment.
• In one 36-patient trial, pathological complete response was 56% in exercisers versus 18% in usual care, but the study was too small to prove a cancer benefit.
• Exercise during treatment improved fitness, strength, and quality of life in several small studies, and walking protected muscle mass in a 44-patient subset.
• Enjoyment and motivational support helped patients adhere; mild fatigue and diarrhoea were common barriers, and dropout rates ranged from 0% to 100%.
• Check with your oncology team before starting; programs in the studies generally involved 2 to 5 sessions weekly of about 30 to 60 minutes.

Understanding Locally Advanced Rectal Cancer and Its Treatment

Rectal cancer accounts for about one in three colorectal cancer diagnoses. It has distinct anatomical, biological, and treatment features compared with colon cancer. Common symptoms at diagnosis include rectal bleeding, altered bowel habits, abdominal pain, reduced appetite, and unexplained weight loss. Without treatment, these symptoms can lead to severe complications, including death.

In England, approximately 7,486 people are diagnosed with rectal cancer every year. Notably, 43% of new diagnoses occur in people aged 75 or older. At the same time, researchers have observed a concerning rise in cases among adults under 50 years old. With cancer diagnoses projected to rise substantially by 2040 due to population aging, understanding the best ways to manage these cancers is increasingly important.

Locally advanced rectal cancer (LARC) — cancer that has grown through the bowel wall or into nearby lymph nodes but has not spread to distant organs — makes up roughly 54% of rectal cancer cases. It creates significant treatment challenges, especially when tumours threaten the surgical margins (the healthy tissue edge around the cancer that surgeons aim to remove).

The standard approach for LARC includes radiation therapy given before surgery, often combined with chemotherapy. This approach, called neoadjuvant chemoradiotherapy, or NACRT, or neoadjuvant radiotherapy (NART) when radiation is given alone, aims to shrink the tumour, make surgical removal cleaner, and lower the chance the cancer will come back in the same area.

Despite these benefits, neoadjuvant treatment causes substantial short-term and long-term side effects. These include fatigue, sarcopenia (loss of muscle mass and strength), reduced physical fitness, impaired heart and lung function, diminished quality of life, and psychological distress. After surgery, recovery may be complicated by poor wound healing and anastomotic leakage (leaking where the bowel is reconnected), with pre-treatment fitness levels emerging as an important predictor of surgical outcomes.

Why Exercise Is Being Studied as a Supportive Treatment

Because cancer treatment takes such a heavy toll on the body, doctors are increasingly interested in what is called "prehabilitation" — strategies that optimise a patient's functional capacity before surgery. The idea is simple: if a patient enters surgery fitter and stronger, they are likely to recover better.

Exercise-based interventions may help by counteracting the physical decline caused by cancer treatment. The potential benefits include reducing fatigue, preserving muscle, and maintaining or improving heart and lung function. But the possible advantages may go beyond fitness alone.

From a radiobiological (how radiation affects living tissue) perspective, exercise could be especially relevant during chemotherapy and radiation. The effectiveness of radiotherapy is strongly influenced by tumour hypoxia — areas of low oxygen inside the tumour. Hypoxia is a recognised contributor to radio-resistance (tumours that do not respond well to radiation) in rectal cancer. Early-phase studies in animals and humans suggest that aerobic exercise can transiently improve blood flow and oxygen levels in tumours, modify the tumour's surrounding environment, and influence immune function. This provides a plausible biological reason why exercise and chemoradiotherapy might work better together than either alone.

Clinically, about 13% of patients with LARC achieve a pathologically complete response — meaning no cancer cells are found when the removed tissue is examined under a microscope. This has raised interest in whether some patients could avoid surgery altogether (called non-operative management) in selected cases. However, researchers do not yet fully understand which patients are most likely to achieve this outcome or how to improve the odds.

A Key Difference: Rectal Cancer vs. Colon Cancer Treatment

One critical distinction between rectal and colon cancer lies in the order of treatments. In the UK, colon cancer is typically treated with upfront surgery, followed by chemotherapy based on the stage found during pathology. Rectal cancer, by contrast, commonly involves radiation or chemoradiation before surgery.

This difference matters for exercise research. Exercise programs for colon cancer patients are usually delivered after curative treatment ends, with a focus on rehabilitation and survivorship — helping people rebuild strength once treatment is over. But in rectal cancer, exercise can be delivered during active neoadjuvant treatment, while patients are undergoing chemotherapy and radiation. This means the exercise interacts with active cancer therapy and its physiological stresses, which has important implications for feasibility (can patients actually do it?), safety (is it safe during intense treatment?), and the potential mechanisms of benefit.

Patients often experience reduced autonomy during neoadjuvant therapy because of intensive treatment schedules and symptom burden. This makes exercise program design — including frequency and duration of sessions — particularly important for whether patients will participate and stay engaged. Understanding how these factors relate to recruitment, attendance, and dropout rates is essential for developing exercise programs that balance real benefits with what patients can reasonably commit to.

How This Research Review Was Conducted

This study is a critical narrative review — a type of research paper that systematically gathers, evaluates, and synthesises findings from multiple studies on a particular question. The researchers followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, which are international standards that help ensure reviews are conducted transparently and thoroughly. They searched three major medical databases — MEDLINE, CINAHL Ultimate, and SPORTDiscus — for studies published between 2010 and 2025. The search was conducted on 15 July 2025 and updated on 21 January 2026, with two reviewers working independently.

The researchers defined who could be included using what is called the PEO framework (Participants, Exposure, and Outcome). Participants had to be adults with LARC who were receiving or preparing for neoadjuvant radiation or chemoradiation. The "exposure" was structured exercise — defined as planned, repetitive bodily movement done to improve or maintain health or fitness — delivered before, during, or after neoadjuvant treatment. Studies had to report at least one of the following outcomes to be included:

• Feasibility measures — how many patients were eligible, how many agreed to join, how many attended sessions, and how many stayed in the study
• Safety measures — adverse events or treatment interruptions
• Functional measures — cardiorespiratory fitness (heart and lung endurance), strength, or quality of life

Both randomised controlled trials (studies where patients were randomly assigned to different groups) and prospective cohort studies (studies that follow a group of patients forward in time) were included, since the research in this area is still limited. Studies focusing only on surgical techniques, medications, or diet-only interventions were excluded.

The initial search identified 25 abstracts after removing 8 duplicates — 23 studies came from MEDLINE, 9 from CINAHL Ultimate, and 1 from SPORTDiscus. Hand-searching of reference lists added 2 more studies. After screening titles and abstracts, 9 studies were excluded (one for duplication, two because they were protocol or methods papers, several because they focused on general colorectal cancer rather than specifically on LARC). This left 16 studies that met all inclusion criteria.

For quality assessment, the researchers used the Critical Appraisal Skills Programme, or CASP, checklists, which are recognised tools for evaluating how well a study was designed and whether its results can be trusted. They did not exclude studies based on quality, because the number of available studies was limited and the focus was on feasibility. Instead, quality ratings were used to guide interpretation. Studies were graded as low, moderate, or high quality.

Because the studies were so different from one another — varying in exercise type, intensity, supervision, and timing — the researchers synthesised the evidence narratively (describing and grouping findings by themes). In addition, they performed limited exploratory statistical analyses using study-level data. They used Pearson's correlation coefficients to look for patterns connecting prescribed exercise frequency (sessions per week) and program duration (number of weeks) with feasibility outcomes like recruitment, attendance, and dropout rates. These analyses were only for generating hypotheses, not for proving cause and effect.

Key Findings: Is Exercise Feasible During Cancer Treatment?

The most important message from this review is that exercise can be successfully delivered to patients undergoing intensive cancer treatment for LARC. But the results varied remarkably from study to study, and not every program worked.

Eligibility and recruitment figures illustrate just how much the picture varied:

• Eligibility rates — the proportion of patients who met the criteria to join — ranged from 27.1% to 100%
• Recruitment rates — the proportion of eligible people who actually enrolled — ranged from 27.5% to 90.0%
• Attendance rates — the proportion of exercise sessions patients attended — ranged from 74.0% to 96.0%
• Attrition rates — the proportion of patients who dropped out — ranged from 0% to 100%

Across the studies, 417 patients were eligible and 226 enrolled, giving an overall recruitment rate of 54.2%. That means just over half of the patients who were eligible for an exercise program agreed to take part. Interpretation of these numbers should be careful though, because attendance and adherence were measured differently in different studies. Some programs reported the proportion of prescribed sessions attended; others reported minutes of weekly exercise achieved; still others used categorical adherence thresholds. This made direct comparisons across studies impossible.

One important lesson comes from a study by Brunet and colleagues (2021). In this Ottawa-based feasibility trial, 10 patients were referred to an exercise program, but zero enrolled. The researchers reported that the program — which planned 12 weeks of supervised aerobic and resistance exercise three times per week at 60–75% of heart rate reserve — simply could not be delivered. They recommended exploring electronic health (eHealth) and hybrid models that combine remote and in-person support instead. This study shows that even well-designed programs can fail if the delivery model does not fit patients' needs during treatment.

Not every program had the same experience, though. At the other end of the spectrum, several studies achieved very high enrolment and strong completion rates. For example, the REx Trial led by Moug and colleagues in Glasgow involved a walking program for patients over age 60 and reported strong feasibility, adherence, and improvements in quality of life.

The exercise quality, when reported, ranged from low to high across studies. Notably, the studies with the strongest results often had clear supervision structures, realistic expectations, and programs designed around patients' circumstances.

Safety: Exercise Was Well Tolerated

Concerns about safety are a common reason doctors and patients hesitate to embrace exercise during cancer treatment. This review found reassuring evidence on this front.

Across all 16 studies, no serious adverse events were reported. The most commonly noted side effects were minor and manageable:

• Mild fatigue after sessions
• Diarrhoea, which is already a known side effect of chemoradiation for rectal cancer
• Back pain in one study (Mast and colleagues, 2025)
• One case of pre-syncope (feeling faint) in the EMPOWER Trial by Loughney and colleagues (2021), which did not progress to a serious event

No studies reported that exercise caused treatment interruptions or interfered with the delivery of chemotherapy or radiation. The absence of serious adverse events was consistent across different modes of exercise — including walking, cycling, resistance training, and high-intensity interval training — and across different treatment phases (before, during, and after chemoradiation).

Safety is particularly relevant for older patients, a group the researchers noted is frequently underrepresented in exercise-oncology research. Several of the included studies — such as the REx Trial, which specifically enrolled patients over 60 years old — showed that even older adults undergoing treatment could exercise safely when programs were appropriately designed.

Functional and Fitness Improvements

Exercise during cancer treatment appeared to help patients maintain or regain physical function. The review found consistent improvements across several domains, though the strength of evidence varied by outcome.

Cardiorespiratory fitness (heart and lung endurance). Multiple studies measured this, often using a test of peak oxygen uptake called VO₂peak or VO₂max — essentially, the maximum amount of oxygen the body can use during intense exercise. Higher values mean better endurance and heart/lung health. The findings were encouraging:

• West and colleagues (2015) studied 39 patients who completed a 6-week, 3-times-per-week cycling program after chemoradiotherapy. Exercisers improved their oxygen uptake at the lactate threshold (VO₂LT — a key marker of fitness), and the program reversed the fitness decline typically caused by chemoradiotherapy.
• Felipe and colleagues (2019), whose 12-patient pilot study in Madrid involved a moderate-to-vigorous group-based program including aerobic exercise, resistance work, and flexibility during chemoradiation, reported improved VO₂peak and increased moderate-to-vigorous physical activity.
• Mast and colleagues (2025), in a small 3-patient feasibility study, found improved VO₂max and reduced treatment toxicity with a hospital-based cycling program.

Muscle strength and muscle preservation. Loss of muscle mass during cancer treatment is a serious problem linked to worse surgical outcomes. Several studies directly addressed this:

• Heldens and colleagues (2016) ran a 9-to-17-week supervised program combining moderate-intensity aerobic and resistance exercise two times per week in 13 patients (9 of whom completed). Leg strength increased by 39.2% and arm strength by 34.9%.
• Singh and colleagues (2018) delivered a 10-week program of supervised resistance and aerobic exercise at 60–80% of maximal heart rate in patients undergoing chemoradiotherapy. Muscle strength improved, loss of appendicular skeletal muscle (the muscle in arms and legs) was slowed, and quality of life was preserved.
• Moug and colleagues (2020) studied a subset of 44 patients from the larger REx Trial with CT-based body composition measurements. Patients who walked during treatment gained muscle mass compared with controls, and the walking program appeared to protect against sarcopenia.

Fatigue and quality of life. Fatigue is among the most common and distressing side effects of chemoradiotherapy. The review found consistent evidence that exercise helped:

• Morielli and colleagues (2016), whose 18-patient feasibility study used supervised moderate-intensity aerobic exercise at a rating of perceived exertion of 12–14 (on a scale where 6 is no exertion and 20 is maximal) three times per week plus a home-based program, reported improvements in quality of life. Patients also reported the program was enjoyable and that motivational support was key to adherence.
• Felipe and colleagues (2019) reported reduced depression scores in their small pilot study.
• Piraux and colleagues (2022), in a 3-arm trial with 18 patients comparing high-intensity interval training (HIIT), resistance training, and usual care during radiotherapy, found attendance of 88–92% and improvements in quality of life across exercise groups.
• The REx Trial (Moug and colleagues, 2019), which followed 48 patients aged over 60, found that a walking program increased daily steps by approximately 3,000 and improved quality of life and reduced depression.

What Helps Patients Stick With Exercise

One of the most valuable strands of this review is what it reveals about the psychology of exercise during cancer treatment. The researchers set out specifically to understand which behavioural and psychological factors are associated with exercise adherence and retention, since this helps future program design.

This research is grounded in a psychological framework called the Theory of Planned Behaviour, which says people's intentions to act are driven by their attitudes (does exercise feel worthwhile?), subjective norms (do the people around them support it?), and perceived behavioural control (do they feel capable of doing it?). The Morielli research group in Canada tested this framework in their feasibility studies. They found that:

• Enjoyment of exercise sessions is important — patients who found the exercise enjoyable were more likely to keep attending
• Motivational support, such as encouragement from staff, boosted adherence
• Barriers commonly included mild fatigue and diarrhoea from treatment

In their 2018 adherence analysis of a subset of patients from the earlier 2016 cohort, the same group found that adherence was linked to gender, mental health status, and baseline physical activity levels. In other words, patients who were already active before treatment, and those with better mental health, tended to adhere better to exercise programs during cancer treatment. This points to the need for extra support for patients who are less active going into treatment or who are struggling psychologically.

The exploratory statistical analyses in this review looked for connections between program characteristics and feasibility. Because the number of studies was small and patient numbers were low (9 studies with quantitative data, 226 patients in total across these), the results should be viewed with caution. The researchers emphasise that these analyses were designed for generating hypotheses to inform future trial design, not to establish cause-and-effect relationships.

Emerging Evidence: Exercise and Tumour Response

Perhaps the most intriguing — and most preliminary — finding concerns whether exercise might actually improve how well tumours respond to chemoradiotherapy. This is a relatively new area of research, and the evidence is not yet conclusive. But what exists is promising enough to demand further study.

Two studies deserve particular attention:

In the EXERT Trial, a Phase II randomised controlled trial led by Morielli and colleagues (2021), 36 patients with Stage II/III rectal cancer undergoing chemoradiotherapy were randomly assigned to either a group doing supervised high-intensity interval training three times per week during the 6 weeks of chemoradiotherapy plus at least 150 minutes per week of unsupervised aerobic exercise after treatment, or to usual care. The results were striking: the pathological complete response rate — meaning no cancer cells were found at surgery — was 56% in the exercisers compared with 18% in the control group. That is a difference of 38 percentage points. The researchers noted, however, that the study was not designed (or "powered") to detect differences in cancer outcomes, so these results, while exciting, need confirmation in larger trials.

In a mechanistic exploratory study by West and colleagues (2019), 35 patients with locally advanced rectal cancer characterised by MRI-defined threatened margins (meaning the tumour was close to the edge of tissue that surgery would remove) exercised after chemoradiotherapy and before surgery. The exercisers showed greater tumour regression (the tumour shrinking or responding to treatment). Specifically, patients who exercised had significantly higher odds of tumour regression, with an odds ratio of 8.5. An odds ratio of 8.5 means the odds of tumour regression in the exercise group were 8.5 times the odds in the non-exercise group — a very large effect. The same study also found that exercise restored fitness levels that had declined during chemoradiotherapy. Again, however, the sample size was small (35 patients) and the study was exploratory.

Mast and colleagues (2025) also reported that at least a 70% tumour response was seen among their small group of 3 patients, but this is far too small a sample to draw conclusions from.

The review authors are careful to note that some of these findings were not statistically powered for oncological endpoints. This is researcher language meaning the studies were too small to definitively prove whether exercise improves tumour response, even when the numbers look impressive. Larger trials are needed before any firm claims can be made about exercise as a way to boost the effectiveness of chemoradiotherapy.

What This Means for Patients

Given the limitations, this remains an emerging research area. Still, several practical takeaways seem reasonable for patients and their clinical teams.

The key message for patients is: if you have locally advanced rectal cancer and are about to undergo chemoradiotherapy, exercise during treatment is likely safe and achievable. It will not interfere with your cancer treatment, and it may carry meaningful benefits for your energy, strength, quality of life, and possibly even your surgical recovery.

There is no single "right" type of exercise. Evidence in this review supports multiple modes:

• Walking programs (as in the REx Trial), which are accessible to most patients and require little equipment
• Supervised cycling at moderate intensity or as high-intensity interval training
• Resistance training with weights or resistance bands
• Combined programs mixing aerobic and resistance exercise

Programs ranged from two sessions per week to five sessions per week, with session lengths of about 30 to 60 minutes. Even a modest program — like daily walking with a step-count target — showed benefits in the Moug studies.

Not all exercise programs succeed for all patients, however. The experience of the Brunet study is a reminder that in-person supervised programs may be impractical for some patients facing intensive treatment schedules. Remote, home-based, and hybrid models (combining some supervised sessions with home exercise) may be useful alternatives and deserve further study.

Skeletal muscle matters. Multiple studies connected a concept called sarcopenia — the loss of muscle mass that accompanies ageing and illness — to poorer outcomes in rectal cancer. In this review, exercise preserved muscle in patients undergoing chemoradiation. This is clinically relevant because patients who maintain their strength going into surgery tend to have fewer complications and recover more quickly.

It is also worth reflecting that across the studies, dropout rates varied from 0 to 100% — meaning some programs completely failed to retain patients. The reasons behind this variation were not always fully documented, but the studies that featured supervised sessions, attention to patient preferences, and motivational support tended to have better adherence.

Limitations of This Review

Several limitations shape how this review's conclusions should be interpreted. It is essential to understand these to avoid overstating what the evidence shows.

First, the total number of studies is small — just 16 — and many had modest sample sizes. The largest quantitative analysis included only 226 patients across 9 studies. Several of the individual studies were very small (3 patients in one, 10 in another). Small samples produce less reliable estimates, and when a study reports results from 3 people, it provides only anecdotal-level evidence.

Second, the studies were highly heterogeneous. They differed in exercise mode (walking, cycling, resistance), intensity (moderate, vigorous, high-intensity interval), frequency (from 1 to 5 sessions per week), duration (from 5 weeks to 17 weeks), supervision (fully supervised, partially supervised, fully remote), and timing (before, during, or after chemoradiotherapy). They also measured outcomes in widely differing ways. This variability makes it difficult to compare studies or combine results.

Third, this was a narrative review, not a meta-analysis. While the researchers used PRISMA reporting standards and systematic search methods, the synthesis was descriptive, and no formal statistical pooling of results was undertaken. Direct comparisons of feasibility across the studies were not possible because researchers reported outcomes using different measures.

Fourth, the review was not prospectively registered on PROSPERO, an international database of systematic reviews. The authors acknowledge this as a limitation because pre-registration helps prevent selective reporting bias. Although they adhered to PRISMA guidelines, the lack of registration increases the risk of reporting bias.

Fifth, data extraction was performed by one reviewer only due to resource constraints, which is another acknowledged limitation. Having two people independently extract data is a safeguard against errors.

Sixth, the exploratory statistical analyses were performed on study-level aggregated data, not individual patient data. This approach cannot adjust for individual patient characteristics, and correlation does not equal causation. The researchers state plainly that these analyses were hypothesis-generating, meant to inform future trial design.

Seventh, and importantly for patients, the oncological findings — particularly the EXERT trial's 56% versus 18% complete response rates — must be considered hypothesis-generating. These studies were not large enough to establish that exercise improves tumour response. The researchers describe these as "emerging" and in need of further research that is properly powered for cancer outcomes.

Finally, the review notes that representation across demographic groups remains limited. Older patients (75 and above), who make up 43% of new diagnoses in England, are underrepresented in many exercise studies. So are patients with significant comorbidities. The REx Trial is a notable exception as it enrolled only patients aged over 60, and its results suggest that walking-based prehabilitation is feasible in this group. But overall, more work is needed to understand exercise delivery in less fit, older, and more diverse populations.

Recommendations for Patients

Drawing from this evidence, here is practical guidance for patients with locally advanced rectal cancer who are considering exercise during neoadjuvant treatment. Always check with your oncology team first before starting any exercise program, and follow their specific advice for your situation.

1. Talk to your cancer care team early. Ask whether they can refer you to a physiotherapist, clinical exercise physiologist, or cancer prehabilitation service. Many hospitals and cancer centres now offer structured support programs, though availability varies.
2. Start where you are, and start small. Even the modest goal of increasing your daily step count showed benefits in the reviewed studies. If you walked 3,000 steps a day before treatment, a target of 6,000 may be realistic. Let your symptoms guide your pace.
3. Aim for a mix of aerobic and resistance exercise if possible. Aerobic exercise — walking or cycling at a moderate intensity where you can still talk — improves heart and lung fitness. Resistance exercise using light weights, resistance bands, or body-weight movements protects muscle mass, which matters for surgical recovery.
4. Consider frequency and duration that fit your life. Programs that worked in the studies generally involved 2–5 sessions per week, lasting roughly 30–60 minutes each. A realistic plan you can stick with is better than an ambitious one you abandon. Use of home-based or hybrid program designs may be particularly helpful when energy is low or hospital visits are frequent.
5. Expect fatigue, and plan for it. Mild fatigue during or after exercise was common in the studies, but it was not a reason to stop. Exercise may also help manage the fatigue of chemoradiation itself over the longer term, even if sessions feel harder on some days. Do not exercise if you have a fever or feel severely unwell, and always report new or worsening symptoms to your team.
6. Use motivational support. Some studies reported that encouragement from staff, family, and other patients helped adherence. Support can also come from a pedometer or activity tracker, which gives you concrete feedback on your progress.
7. If a structured program is not available, self-directed walking is a reasonable alternative. The REx Trial's walking program, which was unsupervised and self-paced, produced measurable improvements in fitness, quality of life, and muscle mass. It involved daily steps with moderate intensity, approximately 3 times the energy cost of resting.
8. Ask about clinical trials. The researchers call for larger trials that properly test whether exercise improves tumour response and long-term cancer outcomes. Participating in research could both give you access to structured exercise support and help answer these important questions for future patients.

Remember that the overarching conclusion of this review is simple and reassuring: exercise during treatment for locally advanced rectal cancer is safe and feasible. At a minimum, it can help you feel better during a difficult time. With further research, it may also prove to be a genuine part of the cancer treatment itself.

Frequently Asked Questions

Is it safe to exercise during chemotherapy and radiation for locally advanced rectal cancer?

Across 16 reviewed studies, no serious adverse events from exercise were reported. Side effects were minor and manageable: mild fatigue after sessions, diarrhoea (already a known effect of chemoradiation), back pain in one study, and one case of feeling faint that did not become serious. No study reported exercise caused treatment interruptions or interfered with chemotherapy or radiation.

Can exercise actually improve how well my tumour responds to treatment?

This is emerging and unconfirmed. In one 36-patient trial, the pathological complete response rate was 56% in exercisers versus 18% in usual care. In a 35-patient exploratory study, exercisers had higher odds of tumour regression (odds ratio 8.5). These studies were too small to prove exercise improves tumour response; larger trials are needed.

What types of exercise were used in these studies, and how often?

Programs included walking, supervised cycling, high-intensity interval training, resistance training with weights or bands, and combined aerobic and resistance exercise. Sessions generally ran 2 to 5 times per week, lasting about 30 to 60 minutes. Even a modest walking program with a daily step-count target showed benefits in the reviewed studies.

Will exercising during treatment help me keep my muscle and strength?

Several studies suggest yes. In a 13-patient supervised program, leg strength rose 39.2% and arm strength 34.9%. In a 10-week program, muscle strength improved and muscle loss slowed. Among 44 patients from a walking trial, those who walked gained muscle mass compared with controls, appearing to protect against sarcopenia.

What does a pathological complete response rate of 56% versus 18% mean?

It means that when removed tissue was examined under a microscope, no cancer cells were found in 56% of exercisers compared with 18% of the usual-care group in one 36-patient trial. This 38-percentage-point difference is striking, but the trial was not designed to detect differences in cancer outcomes, so it needs confirmation.

What helped patients stick with an exercise program during treatment?

Studies found that enjoying the sessions and receiving motivational support, such as encouragement from staff, boosted adherence. Common barriers were mild fatigue and diarrhoea from treatment. One group found adherence was linked to gender, mental health status, and baseline physical activity, suggesting extra support for less active or struggling patients.

What should I do before starting exercise during my cancer treatment?

Always check with your oncology team first and follow their advice. Ask early about referral to a physiotherapist, clinical exercise physiologist, or prehabilitation service. Start small, let symptoms guide your pace, aim for a mix of aerobic and resistance exercise, and do not exercise if you have a fever or feel severely unwell.

If I have locally advanced rectal cancer and I'm deciding whether to exercise during chemoradiotherapy, when should I seek a second opinion?

A second opinion can help when it is unclear whether exercise is safe alongside your specific chemoradiotherapy plan, or when no physiotherapist, clinical exercise physiologist, or prehabilitation service is available to you. It is also reasonable if you have significant comorbidities, are aged 75 or over, or have been told exercise is not an option. A review of 16 studies found no serious adverse events from exercising during treatment, with improvements in fitness, muscle preservation, and quality of life. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

This patient-friendly article is based on peer-reviewed research published in Acta Oncologica, Volume 65, pages 437–448, in 2026. The original article is titled "The impact of exercise interventions before, during, and following neoadjuvant therapies for locally advanced rectal cancer: a critical review" by John Saxton, Chizitara Amadi, Victoria Brown, Mohan Hingorani, and Rajarshi Roy, published under the DOI: 10.2340/1651-226X.2026.44930.

Contact author: Chizitara Amadi, chizitara.amadi-2021@hull.ac.uk. The original article is Open Access, distributed under the Creative Commons Attribution 4.0 International License.