Why you need exercise after a cancer diagnosis

Losing fitness can make fatigue worse, but low intensity exercise can help you stay fit (unless you have severe anaemia (see below). Try to keep active, build your muscles and adjust how hard and often you exercise. Some people find that short, frequent aerobic and cardio sessions are easier; others prefer strength and resistance training, where you can take a rest between sets.

Low red blood cell and/or haemoglobin count is a common side effect of cancer treatment. Symptoms include unexplained tiredness and fatigue. Combined with good nutrition, exercise may help improve these symptoms. For mild or moderate anaemia, try low intensity exercise, with a gradual increase in intensity and/or duration. If anaemia is severe, ask an exercise professional about what exercise to avoid until it improves.

If muscles aren’t being used, they can get smaller and weaker. Lost muscle strength is a side effect of some hormone therapy and steroid treatment. Some treatments also leave muscles tight. Strength and resistance training improves muscle condition.

Starting exercise early in treatment may reduce the risk of lymphoedema (swelling in a part of the body). A lymphoedema practitioner or exercise professional can develop a tailored exercise plan. After lymph node surgery, follow post-operative instructions for exercise and gradually return to activity.

Feeling anxious or depressed during and after treatment is common. Exercise helps the brain to produce chemicals (e.g. endorphins, endocannabinoids) that improve your mood.

Radiation therapy to the chest and some chemotherapy and targeted therapy drugs may damage the heart muscle, making it less effective at pumping your blood. Some hormone therapy drugs, low physical activity and poor nutrition may also increase the risk of heart problems. Aerobic or cardio exercise can help reduce the risk of long-term heart problems.

Cancer and its treatment, particularly hormone and radiation therapy, can have long-term effects on bone strength. Early menopause and reduced levels of physical activity may also cause bones to weaken and break more easily (osteoporosis). Resistance training and exercises where you support your own body weight can help keep your bones strong.

Some hormone therapy and cancer treatments can cause joint pain. Exercise can improve muscle size and strength, flexibility and range of motion, and increase your ability to move, which can help protect your joints and reduce pain.

Weight gain is a common side effect of many treatments, including some types of hormone therapy, and steroids given to manage the side effects of chemotherapy or immunotherapy. People with cancer may also gain weight due to inactivity. Exercise can help you manage weight gain and assist in weight loss, when necessary.

Studies show that physical activity can help improve wellbeing, sex life and libido, brain fog, sleep issues, anxiety, fatigue, pain and how you feel about yourself in general.

Cancer that has spread to your bones (bone metastases or bone mets) and myeloma increase your fracture risk. Some treatments, including radiation therapy and hormone therapy, can also reduce bone strength over time. Your doctor may suggest low-impact activities like walking or swimming, and no contact sports, running or jumping. Resistance exercise can strengthen muscles to support and protect bones, but care is needed. Avoid heavy lifting, high-impact movements, and exercises with fast, forceful or repetitive twisting or bending of the back – unless supervised by an exercise professional. If you have risk factors like bone cancer, myeloma, osteoporosis (thinning of the bones), or are having treatments that weaken bones, ask a doctor and physiotherapist or accredited exercise physiologist what exercise is safe for you.

Some cancers and treatments can weaken your immune system and cause your white blood cell count to drop. This can increase your risk of developing an infection. When your immune system is not working well (called being immunocompromised), it is important to clean any shared exercise equipment before use and avoid public spaces such as gyms, swimming pools and training venues until your white blood cell count returns to a safe level.

Platelets stop bleeding in the body by forming clots. When the platelet count drops, you are at increased risk of bruising or bleeding. It is best to avoid contact sports, cycling and high-impact activities (such as jumping or boxing), as these could cause bruising or bleeding if you get knocked or fall over.

Areas of skin affected by radiation therapy can be extremely sensitive and often uncomfortable. Choose activities and clothing to minimise fabric rubbing on affected areas. Chlorine can irritate the skin, so avoid the pool if you have a rash or your skin is red.

You will likely need to wait for the wound to heal – so follow your surgeon’s or doctor’s advice about when it is safe to start exercise. If you have post-surgery stiffness and pain, you may need an assessment from an oncology physiotherapist or other exercise professional. They can suggest specific exercises to reduce stiffness and pain in the affected area. Pain, weakness, stiffness and reduced movement are common after surgery, but usually improve with time.

Surgery or cancer treatment may affect balance and coordination. This can make you unsteady and lead to a fall. Make sure to exercise in good light where you can see where you’re walking. Avoid riding a bike outside, using a treadmill, or lifting free weights without a training partner. Choose exercises to improve balance and muscle strength, or exercise sitting down.

Some chemotherapy drugs damage nerves, causing numbness and pins and needles in the hands and feet (peripheral neuropathy). This means you could injure yourself without noticing. If you can’t feel your feet, you’re more likely to lose balance or fall, so walk on even surfaces. Ask an exercise professional how to lift weights safely. Some people may find exercise machines safer to use than free weights.

Some chemotherapy drugs and other treatments can damage the heart (cardiotoxicity). In this case, physical activity is still important, but you need specialised exercise advice before exercising.