Part 1 showed you the physiological benefits of exercise before, during and after cancer. Now, let’s get a bit nerdier and look at the physiology of HOW exercise can help treat cancer.
The are 2 leading theories are:
1. Increased Blood Flow
The amazing effects of exercise include improved blood flow through improving the health of blood vessels as well as creating new ones (angiogenesis). This improved blood flow, consequently, improves oxygen other nutrients to the cancer cell. This helps in a few ways.
Firstly (in case you have your shackles raised after reading that delivery of nutrients to the tumour is enhanced!), cancer thrives in hypoxic (low oxygen) environments!! So delivering more oxygen actually assists in weakening the tumour.
Secondly, oxygen and nutrients aren’t the only ingredients in blood. Increased blood flow also improves delivery of the pharmaceuticals including chemotherapy and immunotherapies.
2. Stronger Immune System
Exercise increases adrenaline and noradrenaline which has consistently shown to increase NK Cells (Natural Killer, a type of lymphocyte or white blood cell), which are able to fight the cancer cells. One study reported in my new favourite video showed a significant increase in NK immediately after exercise, and a subsequent 30% suppression of tumour growth after the participants’ serum (10 men) was placed on in-vivo cancer cells.
The 2nd reported study, researching the effect of exercise in lung cancer in mice found a 60-70% reduction in tumour growth! They also showed that exercised muscles released Interleukins, which is a chemical involved in cell signalling, able to ‘direct’ the immune system towards the cancer cell.
3. But wait, there’s more
There is just so much going on, what an amazing machine we live inside of!
Exercise also influences hormones such as insulin and sex-hormones which have been associated with some cancers. It also has positive effects on inflammation as well as oxidative processes in the body.
Exercise and Cancer: The Prescription
- 150 minutes of moderate intensity aerobic exercise per week, throughout the week = 30 minutes of aerobic exercise, 5 times per week or 75 minutes of vigorous intensity exercise.
- 2-3 strength training sessions per week.
That’s the general prescription. However, as per any condition Accredited Exercise Physiologists work with, this would rarely be the first prescription. The program would be progressing towards this when appropriate.
When prescribing exercise to patients we need to consider the individual as a whole: other comorbidities, psychosocial environment, exercise history, current medications and treatment, current symptoms being experienced, medication-side effects, exercise and medication interactions, fitness needs indicated by the type of cancer, fitness needs to return to life and work, and of course, the individual’s goals.
And of course, when designing an exercise program other lifestyle factors need to be considered. In particular, fatigue. Up to 80% of patients receiving chemotherapy or radiotherapy experience fatigue [i]. The National Comprehensive Cancer Network defines Cancer Related Fatigue (CRF) as:
“A distressing, persistent, subjective sense of physical, emotional, and/or cognitive tiredness or exhaustion related to cancer or cancer treatment that is not proportional to recent activity and interferes with usual functioning.”
Exercise Physiologist and Writer
- A Warner and L Jones (2019), Exercise Modulation of Anticancer Therapeutic Tolerability and Efficacy
- P Hojman, Exercise protects from cancer through regulation of immune function and inflammation, Biochemical Society Transactions (2017) 45 905–911
- M Idorn and P Hojman (2016), Exercise-Dependent Regulation of NK Cells in Cancer Protection, Trends in Molecular Medicine 4
- NCCN (2018) Cancer Related Fatigue, NCCN Clinical Practice Guidelines in Oncology
- The evolving role of exercise in Cancer