Why you must exercise

Exercise not only improves cancer treatment and recovery, but also helps prevent the disease, says Parkway Cancer Centre’s Dr Tan Wu Meng.

When one is diagnosed with cancer, changes can be expected in one’s daily life. However, one thing that should not change is the need for regular exercise, both during and after treatment.

The idea of exercising after and even during punishing cancer treatment surfaced in the mid-1980s, according to cancer experts, and coincided with a general growing awareness of exercise and fitness.

Why it is important to stay fit

Dr Tan Wu Meng, a medical oncologist at Parkway Cancer Centre, said that some studies, especially among survivors of breast, colorectal or prostate cancers, have shown an association between exercise and better survival outcomes among cancer patients.

For example, a study sponsored by the National Cancer Institute in the United States in 2006 looked at the effects of moderate exercise on groups of breast and prostate cancer patients undergoing radiation therapy for six weeks.

Those assigned to a daily programme – taking walks of increasing distance and doing exercises with a resistance band – had less fatigue, greater strength and better aerobic capacity than those who did not exercise.

A study in the Journal of Clinical Oncology published in 2008 found that women with breast cancer who increased their physical activity after diagnosis and surgery had a 45 per cent lower risk of death.

One of the most common side effects of chemotherapy is myelosuppression, also known as immunosuppression, where a decreased production of blood cells lowers one’s immune system.

While a patient’s immune system may be compromised during cancer treatment, some patients have the misconception that they should stay at home in order to avoid picking up a bug from passers-by.

Dr Tan said many patients think a cancer diagnosis “means rest in bed even if you are feeling all right”.

“With many cancers and modern treatments, side effects are less challenging than before and patients are more able to lead close to a normal life,” he said, adding that mild exercise such as brisk walking and stretching are within the reach of many patients.

Light outdoor exercise can also boost your immune system.

Dr Tan also said that exercising can help to reduce fatigue and boost the quality of life for cancer survivors.

For example, studies at Boston’s Dana-Farber Cancer Institute have found that non-metastatic colon cancer patients who routinely exercised had lower mortality rate during the study period than their inactive peers, regardless of how active they were before the diagnoses.

Studies show that cancer patients who exercise are up to 50 per cent less tired and depressed and sleep better than patients who do not exercise.

Exercising also helps to reduce fat in the body, which has been linked to tumour growth.

In 2012, researchers at the University of North Carolina found that women who exercised during their childbearing years were less likely to develop breast cancer after menopause.

Lead researcher Lauren McCullough said that exercising helps to cut body fat and excess body fat is linked to higher levels of certain hormones and substances, known as growth factors, which can feed tumour development.

Other studies have shown that gaining weight during and after cancer treatment raises the risk of a cancer recurrence, particularly for breast, colon and prostate cancers.

Exercise also elevates mood, giving patients a natural way of relieving the feelings of depression that some patients experience.

In Singapore, the National Cancer Centre and the National University Hospital are testing a structured support programme for breast cancer survivors and one of the components of the programme includes an exercise regime.

Exercises suitable for cancer patients

Do not attempt strenuous exercises.

Instead, take daily walks of about 30 minutes, not just for the fresh air but to get the body moving as well.

Dr Tan recommends gentle to moderate exercises. “Start slowly and build up to a pace that you feel comfortable with,” he advised.

Other forms of moderate aerobic exercise, such as riding a stationary bicycle, together with the use of light weights for strength training, can improve a patient’s well-being and spur the body’s recovery from treatment.

Exercises such as qigong, tai chi and yoga are also suitable.

Even for patients who are too tired to go out to exercise, simple activities such as stretching and the use of resistance bands – which can be done at home – also work. Even cleaning the home or some gardening is good enough.

Dr Tan said that patients should discuss with their doctors about how their previous treatments may have bearing on their exercise regime or schedule.

“For example, some cancer treatments temporarily reduce the platelet count in the body. In such situations, patients may want to avoid high-impact exercises or sports which may result in falls, bruising or cuts to the skin.”

Keep fit… safely

Avoid pools

Patients who are undergoing radiation therapy should avoid swimming pools as this may expose them to bacteria that may cause infections. The chlorine in the pool water can also irritate radiated skin.

Check with your doctor

Patients who want to exercise should discuss their plans with their oncologists.

Listen to your body

Patients should also note that while it is important to stick to an exercise routine, there will be certain days when treatment leaves them feeling so worn out that it is not possible to exercise. In such situations, always listen to your body and take a rest instead.

Written by Ben Tan



Tags: cancer & exercise, cancer quality of life, cancer survivorship, healthy lifestyle