Often cancer patients are told by doctors to rest when all the evidence suggests that a good dose of exercise could be beneficial, says Dr Karine Nohr
Exercise plays a significant role in the prognosis of many chronic diseases, but we are a little more hazy about its role in patients with cancer.
However it is becoming increasingly clear that exercise has an important role in these patients too. Cancer Research UK advises ‘30 minutes of moderate exercise, five days/week to reduce your cancer risk’, whilst the World Cancer Research Fund recommends ‘if occupational activity is low or moderate, take an hour of brisk walk or similar activity daily and also exercise vigorously for a total of one hour in a week’.
There is now quite a lot of evidence that physical exercise helps to protect against cancer of the bowel and the breast and also there is some evidence that this may be true as well for cancer of the endometrium, the lung and the prostate.
Being overweight or obese increases the risk of developing cancer by 14% and 20% respectively.
Evidence is beginning to emerge that post-diagnosis physical exercise may also be associated with improved longevity in breast and colon cancer. Physical fitness helps to enhance the ability to withstand disease- and treatment- related symptoms and side-effects.
Cancer treatment involves damage to healthy tissue too, so preserving physical health in terms of exercise tolerance, muscle mass and range of motion is clearly advantageous. Many cancer survivors have limitations of physical function and so there is a clear need to rehabilitate these patients as early as possible and maximise their functionality.
Cancer-related fatigue is commonly reported and difficult to treat. Rest, that universal panacea, has probably been overemphasised and can lead patients down the spiral of deteriorating physical functionality and increasing fatigue.
Rest is not best – though a brief period of rest before starting the programme may be advisable for some.
There is encouraging evidence that a graded exercise programme can enable patients to maintain their functionality, The exercises can be subdivided into cardiorespiratory 150 minutes/week (walking, swimming), muscular twice weekly (weights or resistance), flexibility daily (stretching) and lastly specific to a disease e.g. Kegels for prostate cancer or shoulder exercises post-mastectomy.
The benefits outweigh risks of exercise in these patients. Risks include falls, bone fractures, complications of treatment (e.g. cardiotoxicity), pain exacerbation and the possibility of exercise leading to immunosuppression. McNeely et al (2006) have made a very useful list of recommendations in terms of precautions and contraindications to exercise . For example: following an acute infection, avoid exercise until asymptomatic for >48 hours; don’t exercise if platelets <50,000/mm or WCC<3000/mm or Hb<10/dl, or if had vomiting or diarrhoea with 24-36 hours or if severely dyspnoeic or having chest pain or resting pulse>100/m and so on. Most of it is common sense.
Physical activity will also improve general quality of life and also reduce the risk of survivors succumbing to other illnesses such as CVD, depression etc. for which they are at increased risk, which can only be a good thing.
Dr Karine Nohr is a GP in Sheffield
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