Many nonpharmacologic therapies increase both physical and emotional strength during cancer treatment as well as throughout survivorship. These therapies include the mind-body practices of meditation, self-hypnosis, guided imagery, and breath awareness, touch therapies including massage and reflexology, music therapy, acupuncture, better nutrition, and physical fitness. Exercise is also well recognized as a powerful tool to help cope with cancer.
Exercise Decreases Cancer Risk
Many clinical trials demonstrate the benefits of physical fitness in patients with cancer, and physical activity is increasingly acknowledged as a legitimate medical therapy. Insurers in some states reimburse physical fitness programs. The many treatment-related side effects are decreased by exercise, and mounting clinical trial evidence indicates that ongoing enhanced physical fitness not only decreases the risk of developing cancer, but also provides a survival advantage following cancer diagnosis.
More than 200 studies demonstrate decreased cancer risk with increased fitness. The evidence for an association with physical activity is convincing for colon and breast cancers, probable for endometrial cancer, possible for prostate, gastric, and ovarian cancers, and insufficient for all other cancer sites.1
More than 70 studies indicate a more than 25% reduction in risk of breast cancer for physically active vs least active women.
Survival Advantage
The Nurses’ Health Study involving more than 121,000 women showed a strong association between physical activity and outcomes in colon (N = 600) and breast cancer (N = 3,000). Enhanced survival benefits were attributed to the effects on estrogen levels.
In the LACE and Collaborative Women’s Longevity Study, physical activity reduced all-cause mortality. In 832 patients with stage III colorectal cancer, patients who engaged in 6 to 9 hours of physical fitness vs less than 1 hour per week had a 51% decreased risk of dying from colorectal cancer. Those who engaged in 9 or more hours of exercise had a 55% decreased risk of dying from colorectal cancer. The benefit of physical activity was not significantly modified by gender, body mass index, number of lymph nodes, age, baseline performance status or chemotherapy.2
Similar results were found for men with stage III colorectal cancer in the Health Professionals Study,3 and recent meta-analyses confirm this benefit.4
Guidelines for Physical Activity
Sedentary behavior is implicated as an independent risk factor for cancer. The American Cancer Society recommends at least 150 minutes per week of moderate intensity exercise, or greater than 75 minutes per week of vigorous exercise. Ideally, fitness activities are evenly spread throughout the week. Recommendations for cancer survivors are for at least 30 minutes of moderate to vigorous physical activity above usual daily activities, at least 5 days per week5; 40 to 60 minutes of physical activity is preferable. Aerobic activity should be performed for at least 10 minutes and preferably spread throughout the week.
The American College of Sports Medicine recommends reaching 55% of maximum heart rate for sedentary persons and 65% for more physically fit individuals. For additional and more extensive health benefits, the Department of Health and Human Services recommends at least 300 minutes (5 hours) per week of moderate-intensity metabolic equivalent (MET) with MET > 3, or 150 minutes per week of vigorous exercise (MET > 6). The elderly or those at risk for falls should incorporate exercises that improve or maintain balance.
Proposed Mechanisms
Physical fitness and physical activity trigger multiple mechanisms for cancer prevention.6 For hormone-responsive cancers, proposed mechanisms include decreased androgen and estrogen synthesis, enhanced sex hormone–binding globulin synthesis producing decreased circulating hormone levels, and decreased body mass index.7 Lower body mass index is associated with decreased leptin and increased adiponectin, which decreases cancer risk.
Increased physical activity decreases systemic inflammatory response via decreased tumor necrosis factor–alpha, interleukin (IL)-6 and C-reactive protein synthesis. Multiple mechanisms enhance insulin sensitivity, decrease insulin secretion, decrease insulin C-peptide, and decrease IL-17 levels, thereby decreasing the overall inflammatory response. For other cancer types, similar mechanisms are proposed and under active investigation.6
Decreased Physical/Emotional Symptoms
During cancer treatment, exercise decreases physical and emotional symptoms. A Cochrane review involving 4,800 patients showed that moderate or vigorous exercise produced better quality of life and physical function, decreased fatigue and anxiety, and enhanced sleep quality compared with less active individuals.8
Ongoing physical activity produces major improvement in muscle strength, aerobic capacity, enhanced quality of life, decreased fatigue, and improved overall emotional status.9 Better functional capacity, decreased chemotherapy-induced nausea, decreased dyspnea, and less memory loss were seen in physically active patients.
Not All Workouts Are Equally Beneficial
Fitness programs that combine aerobic and resistance training produce the greatest benefits.10 Aerobic conditioning enhances cardiovascular oxygen delivery and increases oxidative capacity. Resistance exercises decrease muscular weakness, and fitness that combines both aerobic and resistance training provide the greatest benefit in enhancing maximal oxygen consumption.11
Data show that less than 10% of survivors are physically active during treatment, and only 25% will be active after treatment. Support groups and special programs for cancer survivors, such as SHARE and Gilda’s Club, may help enhance fitness participation.12
Yoga: An Increasingly Popular Fitness Choice
There are multiple exercise possibilities for patients, such as aerobic training, resistance strength training, stretching, yoga, tai chi, Qi Gong, and so forth. Yoga is the sixth most used complementary health practice according to National Health Interview Surveys, and yoga’s popularity is increasing.13 Thirteen million people practice yoga.
The physical benefits of yoga in cancer groups include enhanced perceptual and motor skills, increased cardiovascular function, increased flexibility, fitness and muscle strength, balance, improved blood glucose and lipid profiles, decreased fatigue and pain, improved sleep, decreased joint pain and decreased muscular stiffness.5,14 Yoga requires little space and requires no equipment.
Vigorous yoga provides benefits similar to those gained with treadmill workouts.15,16 It can provide fitness benefits that approach those of treadmill performance in terms of MET expenditure and percent maximum heart rate. While kilocalorie expenditure and maximal oxygen consumption are less than that of treadmill at 3.5 mph (5.6 kph), they are higher than treadmill at 1.9 mph (3.2 kph), and at least 10 minutes of vigorous yoga provides a fitness level at the moderate intensity recommended by the American College of Sports Medicine to improve cardiovascular fitness. Yoga also incorporates weight-bearing resistance.
Yoga’s anti-inflammatory effects are well demonstrated. A cross-sectional study of 50 healthy women who were either yoga novices or seasoned practitioners produced additional data. Leptin and adiponectin was measured on three occasions in these women, who were matched on potential confounding factors including body mass index, central adiposity, and cardiovascular fitness. Leptin was 36% higher in the yoga novices vs the experts (P = .08), but the adiponectin-to-leptin ratio in yoga experts was nearly twice that of the yoga novices (P = .009).18
Many forms of fitness are available to suit virtually all patient and survivor preferences. Vigorous yoga is a popular option. It provides benefits similar to those of more traditional approaches, such as treadmill and weight-bearing resistance, and may help encourage more patients to engage in survival-enhancing physical activity. ■
Disclosure: Drs. Wesa and Cassileth reported no potential conflicts of interest.
Dr. Wesa is an integrative medicine specialist at Memorial Sloan Kettering Cancer Center, New York.
References
1. Steindorf K, Leitzmann M, Friedenreich C: Physical activity and primary cancer prevention, in Ulrich CM, Steindorf K, Berger NA (eds): Exercise, Energy Balance, and Cancer, pp 83-106. New York, Springer, 2013.
2. Meyerhardt JA, Giovannucci EL, Holmes MD, et al: Physical activity and survival after colorectal cancer diagnosis. J Clin Oncol 24:3527-3534, 2006.
3. Meyerhardt JA, Giovannucci EL, Ogino S, et al: Physical activity and male colorectal cancer survival. Arch Intern Med 169:2102-2108, 2009.
4. Je Y, Jeon JY, Giovannucci EL, et al: Association between physical activity and mortality in colorectal cancer: A meta-analysis of prospective cohort studies. Int J Cancer 133:1905-1913, 2013.
5. Buffart LM, Galvão DA, Brug J, et al: Evidence-based physical activity guidelines for cancer survivors: Current guidelines, knowledge gaps and future research directions. Cancer Treat Rev 40:327-340, 2014.
6. Courneya KS, Friedenreich CM: Physical activity and cancer: An introduction. Recent Results Cancer Res 186:1-10, 2011.
7. Lynch BM, Neilson HK, Friedenreich CM: Physical activity and breast cancer prevention. Recent Results Cancer Res 186:13-42, 2011.
8. Mishra SI, Scherer RW, Geigle PM, et al: Exercise interventions on health-related quality of life for cancer survivors. Cochrane Database Syst Rev 8:CD007566, 2012.
9. Cramer H, Lange S, Klose P, et al: Yoga for breast cancer patients and survivors: A systematic review and meta-analysis. BMC Cancer 12:412, 2012.
10. Irwin ML: Benefits of aerobic and resistance exercise in cancer survivors, in Berger NA, Steindorf K, Ulrich C (eds): Exercise, Energy Balance and Cancer, pp 199-214. New York, Springer, 2012.
11. Jones LW: Physical activity and lung cancer survivorship. Recent Results Cancer Res 186:255-274, 2011.
12. Bourke L, Homer KE, Thaha MA, et al: Interventions to improve exercise behaviour in sedentary people living with and beyond cancer: A systematic review. Br J Cancer 110:831-841, 2014.
13. Perrgoy JA, Clarke TC, Jones LI, et al: Regional variation in use of complamentary health approaches by U.S. adults, in NCHS Data Brief, no. 146. Hyattsville, Maryland, National Center for Health Statistics, National Institutes of Health, April 2014.
14. Buffart LM, van Uffelen JG, Riphagen II, et al: Physical and psychosocial benefits of yoga in cancer patients and survivors, a systematic review and meta-analysis of randomized controlled trials. BMC Cancer 12:559, 2012.
15. Hagins M, Moore W, Rundle A: Does practicing hatha yoga satisfy recommendations for intensity of physical activity which improves and maintains health and cardiovascular fitness? BMC Complement Altern Med 7:40, 2007.
16. Clay CC, Lloyd LK, Walker JL, et al: The metabolic cost of hatha yoga. J Strength Cond Res 19:604-610, 2005.
17. Kiecolt-Glaser JK, Bennett JM, Andridge R, et al: Yoga’s impact on inflammation, mood, and fatigue in breast cancer survivors: A randomized controlled trial. J Clin Oncol 32:1040-1049, 2014.
18. Kiecolt-Glaser JK, Christian LM, Andridge R, et al: Adiponectin, leptin, and yoga practice. Physiol Behav 107:809-813, 2012.
Integrative Oncology is guest edited by Barrie R. Cassileth, MS, PhD, Chief of the Integrative Medicine Service and Laurance S. Rockefeller Chair in Integrative Medicine at Memorial Sloan Kettering Cancer Center, New York.
The Integrative Medicine Service at Memorial Sloan Kettering Cancer Center developed and maintains a free website—About Herbs (www.mskcc.org/aboutherbs)—that provides objective and unbiased information about herbs, vitamins, minerals, and other dietary supplements, and unproved anticancer treatments. Each of the 268 and growing number of entries offer health-care professional and patient versions, and entries are regularly updated with the latest research findings.
In addition, the About Herbs app, Memorial Sloan Kettering Cancer Center’s very first mobile application, is compatible with iPad, iPhone, and iPod Touch devices, and can be downloaded at http://itunes.apple.com/us/app/about-herbs/id554267162?mt=8.
