Exercise for cancer cachexia
Cancer cachexia refers to a devastating wasting syndrome featuring marked weight loss, muscle and fat mass wasting, lack of appetite, fatigue, malabsorption, nausea, profound changes to the endocrine system and disruption of protein, lipid, and carbohydrate metabolism. Up to 50% of patients experience cachexia. It may be aggravated by chemotherapy and it reduces a patient's quality of life.
Researchers Fabio Santos Lira, JC Rosa, and M Seelaender published a paper in the journal Applied physiology, nutrition & metabolism, 39: 679-686 (2014) briefly reviewing the current understanding of how exercise may assist cancer patients experiencing cachexia.
Below are summary points:
- sustained systemic inflammation is a major contributing factor in the physiology of cachexia
- aerobic exercise at 40-70% of maximal oxygen consumption for 30-60 minutes, 3-6 times/week and strength exercises, have been shown to modulate inflammation in cachectic conditions
- animal models have shown that resistance training decreases proteolysis (protein breakdown), and increases protein synthesis (protein formation), through activation of the mTOR pathway by augmenting levels of insulin growth factor-1 in cachexia.
- resistance training protocols of: 50 - 80% 1-repetition maximum alone or with pharmacological / nutritional therapy induces increased strength, protein build up and cell mass and results in improved quality of life in human patients with chronic diseases associated with cachexia
- The American Cancer Society recommends cancer patients maintain as much physical activity as possible during cancer treatment and recovery (eg. 150 mins/week, moderate intensity activity).
- moderate intensity activity does not interfere with the efficacy of chemotherapy.
- mechanism of how exercise impacts systemic inflammation: regulation of immune system, changes in blood flow, reducing pro-inflammatory factors, increasing anti-inflammatory markers, improving oxidative metabolism, modulating central and peripheral nervous system function.
Concluding remarks from the authors of the paper:
"Chronic endurance exercise prevents/attenuates the symptoms of cancer cachexia in animal models. Therefore, we propose that endurance exercise training may present a low-cost, safe alternative for sustained inflammation in cancer patients, provided that cardiovascular status is compatible with the load of exercise prescribed. The adoption of combined strength / endurance exercise training may also represent an interesting possibility. Given this potential, it is clear that there is much to be done to broaden the spectrum of studies regarding both the effects of chronic exercise in patients and the mechanisms involved. For the latter, animal models may be an interesting alternative."
Lira, FS, Neto, and Seelaender M. Exercise training as treatment in cancer cachexia. Appl. Physiol. Nutr. Metab. 39:: 679-686 (2014)