How does exercise help against cancer?
“If we could give everyone the right dose of food and exercise, not too much and not too little, we would have found the best way to health,” said the ancient Greek physician Hippocrates. This ancient wisdom can now be backed up by scientific findings: According to this, regular and appropriate physical activity as part of an otherwise healthy lifestyle (balanced diet, fresh air, little stress, enough sleep, no alcohol and nicotine) can counteract various diseases – in addition to cardiovascular diseases, dementia and certain metabolic diseases, these also include cancer.
Sport reduces the risk of common types of cancer
For some types of cancer, an active lifestyle can reduce the risk of the malignant tumor developing in the first place (primary prevention). This has already been proven for seven common types of cancer:
The risk of developing lung cancer can apparently also be reduced through exercise – at least in smokers. No such effect has yet been demonstrated in non-smokers.
In contrast, there is a negative correlation between black skin cancer (malignant melanoma) and sport: people who are active in sport are up to 27 percent more likely to develop this dangerous form of skin cancer. However, this is probably due to the fact that such people spend a lot of time outdoors and are therefore exposed to more UV light. Without adequate UV protection, the risk of skin cancer increases significantly!
When exercising outdoors, remember to protect yourself adequately from the sun’s UV rays by wearing sunscreen and clothing with UV protection.
Sport slows down the progression of cancer
According to studies, regular exercise can also reduce the likelihood of dying from an existing cancer. Physically active patients therefore have a higher chance of surviving longer. Sport inhibits the tumor from growing and spreading to a certain extent. Researchers have already observed this for breast, bowel and prostate cancer.
Findings from observational studies and laboratory studies
It should be noted that the previous studies were so-called observational studies, from which only a connection between sport and cancer, but no direct effect, can be deduced. Unfortunately, this is also difficult to prove. Nevertheless, scientists are currently trying to investigate the effect of sport in more meaningful studies.
At least in the laboratory, researchers have already been able to prove in tumor cell cultures and in animal experiments that sport can slow down the growth of tumor cells. Researchers have also been able to prove that regular endurance training in particular mobilizes certain immune cells – especially so-called natural killer cells (a group of lymphocytes). These immune cells can recognize and kill malignant cells. In exercising mice, for example, tumors grew more slowly and fewer tumor metastases were formed.
However, sport and exercise are no substitute for cancer therapy! However, they can supplement and support treatment!
Sport suppresses chronic inflammation
With a balanced diet and exercise, the stress in the fatty tissue can be reduced. The unwanted fat itself also melts away and muscle mass grows. In addition, regular exercise training promotes anti-inflammatory processes. Overall, sport reduces the level of inflammation in the body and therefore also the risk of cancer.
Sport increases quality of life
Cancer is exhausting. The body needs a lot of strength to fight the tumor, but also to endure the therapy and its side effects. Training that is individually tailored to each patient has been proven to improve their physical performance:
Mobility, muscle strength and endurance increase. Fat is reduced, the immune system is strengthened and the risk of falling is reduced. In addition, exercise increases self-esteem and well-being – also because the patient contributes to their own health.
Sport reduces side effects and long-term complications
Another significant benefit of exercise in cancer: individually tailored exercise programs before, during and after cancer treatment reduce the side effects caused by the tumor itself and the therapy. These include, for example
- Tiredness and chronic exhaustion (fatigue)
- Therapy-related nerve damage (polyneuropathy)
- incontinence
- Water retention in the tissue due to impaired lymphatic drainage (lymphoedema)
- sleep disorders
- Anxiety and depression
Sport in cancer can help patients to tolerate the therapy better. It can then be carried out more frequently in accordance with the guidelines and thus be effective. Physically active patients also recover more quickly after treatment. In addition, the number of blood transfusions required is reduced.
Does sport reduce the risk of relapse?
It has not yet been sufficiently clarified whether sport reduces the risk of the cancer flaring up again after treatment (risk of relapse or recurrence) or the formation of metastases. However, there is evidence that regular and sufficient physical activity can reduce the risk of cancer recurrence.
For example, the risk of recurrence for older breast cancer patients appears to be increased if they remain very overweight and take little exercise after their illness. There is similar data for colorectal cancer patients: Inactive patients die earlier than those who exercise a lot. Prostate cancer patients can apparently also positively influence their prognosis if they exercise regularly.
When should cancer patients exercise?
Exercise before, during and after cancer treatment is safe and beneficial for almost all stages of the disease.
Exercise already in hospital
Exercise in rehabilitation
At the end of or after their initial cancer treatment, most patients are initially instructed individually in exercise at a rehabilitation clinic or in an outpatient rehabilitation facility – by physiotherapists, sports instructors or other specialists. There they also learn, for example, how to deal with an artificial bowel outlet (stoma) or other restrictions such as prostheses, as well as how to avoid incorrect or relieving postures. And patients who have had lung surgery practise special breathing techniques to make the best possible use of their lung capacity.
Sport after rehabilitation
After rehabilitation, the doctor and patient decide together on further exercise and sports training. Various points need to be considered, for example: Do the course of the illness and the individual’s state of health allow regular exercise at all? Which types of sport make sense for the patient? To what extent is training advisable?
In order to clarify such questions, cancer patients should ask themselves before starting their training…
- seek advice from their attending physician in this regard and
Patients should then consult a trained sports or physiotherapist and receive professional support during their training.
Keep your own record of the course of your illness and the type, quantity and duration of medication you take. You can present this overview to your doctor so that he or she can give you expert advice on sports training.
Sport is also important after you have recovered from cancer: incorporate exercise and physical activity into your everyday life on a permanent basis.
When should caution be exercised?
In the case of certain contraindications, an exercise program must first be clarified with a doctor and possibly restricted:
- Serious concomitant illnesses (e.g. cardiovascular diseases, chronic joint inflammation)
- Balance disorders
- Unintentional severe weight loss as a result of the cancer (tumor cachexia)
- metastases of the tumor in the bone (bone metastases), “holes” in the bone tissue (osteolysis)
- Advanced osteoporosis
- Chemotherapy infusion in the last 24 hours
- Phase between radiotherapy sessions
- Anemia with a hemoglobin level below 8g/dl
- pronounced lymphoedema
- newly created artificial bowel outlet (stoma), permanent catheter for draining urine or feeding tube
Patients with concomitant diseases such as cardiac arrhythmia should only exercise under supervision!
When is sport forbidden in cancer patients?
Although sport is almost always recommended, some circumstances prohibit physical training:
- High risk of infection, acute infections or fever
- Immediately after an operation (nevertheless get moving again as quickly as possible with independent personal hygiene in hospital and coping with everyday life at home)
- severe pain
- acute bleeding
- Acute nausea and/or vomiting
- severe dizziness
- Bone metastases or osteolysis at risk of fracture
- vascular occlusion due to blood clots (thrombosis, embolism) within the last ten days
- ongoing irradiation of the heart area or whole-body irradiation
Which sports are suitable for cancer?
As a motivational aid for more activity in everyday life, you can count your daily step count – via an app or with a wearable activity tracker.
Individual and guided sports program
Together with your doctor or a physiotherapist, draw up a detailed training plan that is realistic for you. Be happy about even small progress in your training and don’t expect too much of yourself. Most people find exercise easiest when they train together with others and have fun doing it.
It is important that you start exercising slowly to get used to it and then exercise regularly. You should always pay attention to your daily form: If you are feeling less well, choose a light workout. If you feel well, you can train more intensively – but without overexerting yourself! It is therefore better to follow an exercise plan that is tailored to you and not sports programs for healthy people.
For patients with an artificial bowel outlet (stoma), almost all types of sport are possible after the first few weeks – depending on the state of health and side effects of the therapy – including swimming. The prerequisite is that the stoma is securely and tightly fitted.
Assessing training intensity
In order to find the right level of training, i.e. the intensity, for each individual patient, specialists can carry out performance diagnostic tests. However, patients can also assess the level of exertion themselves using the so-called “Borg scale”. This starts at 6 (“not strenuous at all”) and goes up to 20 (“maximum effort”). In this range, you determine for yourself how strenuous the training is. For example, endurance training should be between 12 (moderate intensity) and 14 (higher intensity) on the Borg scale – you should perceive it as “somewhat strenuous”. Strength training, on the other hand, can be “strenuous”, which is between 14 and 16 on the Borg scale.
Combining sports effectively
- Endurance training three times a week at medium intensity for at least 30 minutes over a period of at least eight to twelve weeks
- In addition, strength training at least twice a week with at least two sets of eight to 15 repetitions
In addition, the American College of Sports Medicine (ACSM) has specifically listed which frequency and intensity are most suitable for typical symptoms of cancer patients. These so-called FITT (“frequency, intensity, time, type”) criteria help your doctor and physiotherapists to plan your individual sports and exercise program.
In general, these recommendations are only scientific guidelines. You should base your program on how you feel and what you can do – any exercise is better than none!
Endurance training
Suitable endurance sports are:
- Running or Nordic walking
- cycling
- Cross-country skiing
- Training on endurance equipment such as ergometers or steppers
- Aquajogging
- Swimming (as long as there is no increased susceptibility to infection)
- Dancing
If you are weakened (e.g. during therapy), intermittent endurance training is suitable at first. This involves alternating between exertion and breaks in a rhythm of, for example, two minutes. You can then gradually lengthen the exercise phases and shorten the breaks until you can train continuously for 30 to 60 minutes at a moderate intensity or 10 to 30 minutes at a higher intensity.
If you are fit, you can also increase your endurance more quickly by alternating intensive and moderate training in 4-minute intervals (extensive interval training).
Strength training
Another positive effect of strength training is that it can prevent the development of lymphoedema in the arm. Patients who have had lymph nodes removed in the armpit area, for example, are susceptible to this type of oedema. If mild to moderate arm lymphoedema is already present, training reduces the sensation of pain and pressure.
After lymph node surgery or if you have lymphoedema, wear loose-fitting sportswear that does not constrict the affected areas of the body in the armpit or groin. If you have been prescribed a compression stocking, it is best to wear it during training.
Patients with bone infarcts (osteonecrosis), which can occur as a result of cancer treatment, also benefit from exercises that strengthen the muscles around the affected joints (often hips or knees). Light strength training can be supplemented with endurance sports that are easy on the joints, such as water aerobics, cycling and training on the cycle ergometer.
Training tips
Protect fresh surgical scars from the sun, heat, cold, pressure or abrasive clothing. Treat the scars with ointments or oils. Physiotherapists can also mobilize scars to promote healing.
Stretching exercises
Exercises for strength and endurance should be supplemented by stretching exercises, as they increase mobility. Stretching exercises should be performed slowly and in a controlled manner. Avoid jerky movements so as not to pull a muscle.
Coordination/sensomotor training
After a short warm-up, coordination exercises are useful before endurance and strength exercises. Perform these slowly and in a controlled manner. Older patients in particular benefit from this, as coordination training improves the sense of balance and can therefore prevent falls.
Peripheral polyneuropathy can hardly be treated, but it can be alleviated through sensorimotor training. Training is most effective if it is carried out two to six times a week for six to 30 minutes at a time and for at least four weeks.
Pelvic floor training
As a result of pelvic surgery (e.g. for prostate, bladder or rectal cancer), the closing mechanisms of the bladder, anus or pelvic floor and, in some cases, nerves can be damaged. The consequences are urinary or fecal incontinence. Systematic pelvic floor training is very effective in restoring continence. Physiotherapists work with you to train the pelvic floor, take account of scars on the abdominal wall in their exercises and also promote your general fitness with certain exercises.
Yoga
Most of the data on yoga and cancer has been collected from breast cancer patients. According to several studies, yoga increased the quality of life of those affected both during and after cancer treatment and reduced symptoms of fatigue. Yoga also improves sleep, cognition, lymphoedema and vitality in cancer patients.
What you should bear in mind
If you have physical limitations, you may need to use yoga aids such as blankets, rollers, straps and blocks. If you have bone metastases or a brain tumor, some exercises must be adapted accordingly.
It is best to practise yoga with a yoga teacher with additional training in oncological sports.
Qi Gong
Like yoga, the Chinese form of meditation, concentration and movement Qi Gong strengthens body and mind. Strength, flexibility, coordination and concentration are trained. At the same time, regulating the breath, mediation and relaxation play a decisive role. All of this together helps cancer patients to improve their quality of life, reduce tension and alleviate the side effects of therapy.
Dancing
Which sport may be unsuitable for cancer?
Cancer patients must decide individually with their doctor what type of exercise is suitable for them and at what intensity. Some types of sport are not suitable for some patients.
No endurance sports in case of unintentional weight loss
Patients who have unintentionally lost or are losing a lot of weight (tumor cachexia) should not do any endurance training. Instead, they should continue to try to cope with everyday life themselves and be regularly active for short periods at low intensity. In addition, these patients need individually adapted strength training supervised by specialists (e.g. with a fitness band or their own weight) to counteract the loss of muscle mass.
Caution when swimming during radiotherapy
In principle, swimming is an endurance sport that is easy on the joints and is also suitable for cancer patients. However, patients undergoing radiotherapy should not swim in chlorinated or salt water.
No cycling after surgery in the small pelvis
Gymnastics and martial arts unfavorable for people with a stoma
Gymnastics is not suitable for people with an artificial bowel outlet (stoma). Training on horizontal bars and parallel bars in particular is not recommended. Martial arts should also be avoided.
No martial arts and ball sports with lymphoedema
Patients with lymphoedema in the arms or legs should avoid martial arts.
Patients with a risk of lymphoedema or already developed lymphoedema should not perform any movements that are too vigorous or jerky. This could provoke lymphoedema or exacerbate existing lymphoedema. Ball sports such as tennis or soccer are therefore less suitable.
Competitive and extreme sports are not advisable
Intensive training can help to quickly build up stamina and strength again. However, very high intensities such as competitive or extreme sports are not recommended for cancer patients during and shortly after treatment. This is because they temporarily strain the immune system, which increases the risk of infection.
Play and sport with children with cancer
Sport not only improves fitness and mental well-being in adult cancer patients – children also seem to benefit from it. Some of the young patients are cheerful despite their cancer and want to exercise and play with their peers. However, there are also children with cancer who are insecure, withdraw into themselves and remain inactive for a long time – for example because their bodies have changed as a result of operations (possibly even amputation). In addition, many children – like adults – suffer from chronic exhaustion (fatigue) or balance problems as a result of cancer. They are therefore unable to keep up with healthy children and are ostracized or hold themselves back.
It is therefore important to motivate children with cancer to take part in regular exercise and sport as early as possible. This can improve their fitness in the long term and reduce the likelihood of late effects.
