Cancer is a condition where cells in a specific part of the body grow and reproduce uncontrollably.
Whilst there are numerous variations in type and treatment, physical activity is seen to be beneficial regardless of the condition specifics.
Benefits of physical activity
Some studies show that it can help to speed up recovery after cancer treatment. Regular exercise can reduce stress and give you more energy. Other benefits include a positive effect on:
- Mood- One research study found you are less likely to be anxious or depressed through weekly exercise. The sooner you start after treatment has finished the better.
- Fatigue- Tiredness & weakness are a side effect of cancer treatment, this can be countered through a moderate programme of physical activity.
- Osteoporosis- Weight bearing exercises such as running, lifting & impact, prevent thinning of the bones to protect against osteoporosis.
- Start small. The biggest improvements come from making small changes that you can increase safely and incorporate into your daily routine. Like taking the stairs not the lift; Parking at the back of the car park not by the door; Getting off the bus a stop early; Walk short journeys.
- Gentle aerobic activities are best – try starting with a gentle walk, bike ride, or swim.
- Strength building activity is also important. Try yoga or some resistance work to keep muscles strong.
- Notice the days & times when you feel you have more energy & use those times to build on you activity levels.
- Chair-based exercises can be done at home and are a great way to get started back into physical activity. There are lots of home-based activities that you can do to improve strength, stamina, and flexibility: mowing the lawn, digging in the garden or pushing a wheelbarrow, or doing chair-based exercises.
- Gradually increase to 20-30 minutes of exercise to breathlessness each day, starting small with gradual steps aiming to increase your exercise capacity.
- When you're ready, try some more sociable exercises, like doubles badminton, dancing, yoga, Qi Gong, Tai Chi, or brisk walking with a friend. Exercising with a friend can help keep you committed.
- Try using an app like Public Health England's Active 10 app to monitor your walks and ensure you're walking briskly.
- As your strength, confidence and stamina improves, try to aim for the recommended 150 minutes moderate activity per week. This can be broken down into bouts of 10 - 20 minutes whenever you can fit it in.
The science. How does being active reduce the risk of cancer?
Hormones - Being active can affect the levels of some hormones in our body. Hormones are chemical messages that are carried around our body to tell different parts what to do. Oestrogen and insulin are both hormones.
Cancer starts when cells divide too much and multiply out of control. Oestrogen could encourage cells in the breast to divide more often. If you're doing a lot of activity it can reduce the levels of oestrogen, helping to prevent breast cancer. 
Insulin could also affect how cells multiply. Being very active can reduce levels of insulin and help prevent cancer.
Inflammation - The bowel helps us use the food we eat. It also processes waste which passes out of our bodies as excrement.
Being active helps move food through our bodies. This reduces the amount of time any harmful chemicals in food waste are in contact with our bowel, helping to prevent cancer.
Being active also helps control levels of inflammation in the bowel. Inflammation is a normal way our bodies respond to damage. But if there is too much, it can cause our cells to multiple more often increasing the risk of cancer. So being active can help prevent bowel cancer by reducing the levels of inflammation.
Protein - specific antigen or PSA is a protein produced by cells of the prostate gland. PSA level which is measured in the blood can help show if prostate cancer is growing.
Early data suggests that exercise might be beneficial in terms of helping regulate the way that cancer cells grow and repair DNA. There is some evidence that physical activity can be a good tool to stop cancer returning post treatment.
The idea that exercise training might help control prostate cancer progression also comes with much fewer side effects & a potential reduced need for invasive treatments such as surgery, radiotherapy or hormone therapy.
In general, its recommended to do the same level of activity for people with cancer as for the general population, 150 minutes of moderate physical activity per week.
When to avoid exercise
People with certain types of cancer or having particular treatments might need to avoid some types of exercise. There are some situations where you need to take extra care. For example, if you have stomach or other digestive system cancers or cancer that has spread to the bone, you shouldn't do heavy weight training.
Cancer affecting your bones - If you have cancer affecting your bones, you might be more at risk of a break or fracture. You must avoid putting too much strain on the affected bones. You could try swimming or exercising in water, as the water supports your body weight so the skeleton isn't stressed. Exercise such as yoga generally appears safe for everyone.
Low immunity - People with low immunity due to treatment, need to avoid exercising in public gyms & pools. Ask your medical team when it is safe to start exercising in the gym with other people.
Peripheral neuropathy - Some people have loss of sensation, or feelings of pins and needles, in their hands and feet due to cancer treatments. This is called peripheral neuropathy. If you have this it might be better to use a stationary bike than to do other types of weight bearing exercise.
Breast cancer - Women with breast cancer can do upper body training but it should be done very slowly.
Visit your GP for a check-up if you haven't exercised before; if returning from injury or if you're returning to exercise after a long break. Always seek advice from you GP & if advised to, do not to exercise.
Further information about cancer and physical activity
Moving Medicine: Being active is important for cancer (PDF, 958 Kb)