Exercise has positive benefits for every organ system in the human body. That should come as no surprise! We know that exercise is protective against cardiovascular disease, but what about another common health problem that befalls people as they age, cancer? According to ourworldindata.org, every sixth death is due to cancer. Can exercise lower the risk?
Genetics impacts cancer risk, but so does lifestyle. According to the World Health Organization, 30 to 50% of cancers are preventable through lifestyle. You’re probably aware that not smoking or abusing alcohol can lower your risk, but exercise can reduce the risk of some types of cancer too. Some cancers that regular physical activity may reduce the risk of include cancers of the colon, esophagus, breast, lung, kidney, liver, and bladder.
Have you ever wondered how exercise might reduce the risk of cancer? Let’s look at some changes that happen “behind the scenes” when you exercise that may reduce the risk of developing cancer.
The Effects of Exercise on Myokines
When you contract your muscles during exercise, muscle cells release myokines, peptides with physiological functions in the body. Studies show that myokines slow the proliferation of cancer cells in culture and in animal models.
Scientists believe that myokines may play a role in the anti-cancer benefits of exercise and some of the other health benefits you get when you work out regularly. Myokines affect communication between tissues and organs and influence metabolic function. Research suggests they may be beneficial for preventing and treating type 2 diabetes and obesity too.
Skeletal muscles release hundreds of types of myokines when they contract, and scientists have only studied a small number. So, there’s a lot more to learn. In addition, studies show that myokines may reduce muscle loss in people with advanced cancer.
Exercise Impacts Hormones Too
Another way exercise may lower the risk of some forms of cancer is its impact on hormones. Exercise lowers circulating estrogen in women and that may be a mechanism by which it reduces the risk of estrogen receptor-positive breast cancer. Estrogen fuels the growth of estrogen receptor-positive breast cancer and treatments that block estrogen can prevent and treat this type of breast cancer. By reducing estrogen, exercise reduces the quantity of estrogen that binds to estrogen receptors on breast tissue and stimulates the growth of cancer. High estrogen also increases the risk of uterine cancer, another cancer that regular workouts lower the risk of.
Effects of Exercise on the Immune System
The best natural defense against cancer is a healthy immune system. Scientists say that our bodies are constantly producing cancer cells that our immune system recognizes and destroys, but as we age, the immune function becomes less robust and the immune system may miss some of these abnormal cells, allowing them to gain a foot hold in the body.
One type of immune cell that vanquishes tumor cells and other invaders, like viruses, is the natural killer cell, a type of immune cell. When natural killer cells encounter a tumor cell or a cell infected by a virus, they release chemicals called cytokines that recruit more immune cells into the area to tackle and take down the unwanted cells.
What does this have to do with exercise? When you exercise, your adrenal glands produce more epinephrine and norepinephrine and send it into the bloodstream. In turn, increased norepinephrine and epinephrine recruits more natural killer cells into the circulation to destroy abnormal cells that could become tumors.
Body Weight Benefits of Exercise
One reason people exercise is to lose weight. Maintaining healthy body weight is important for cancer prevention since obesity is linked with at least 13 types of cancer. According to the Centers for Disease Control and Prevention, around 40% of all cancers can be attributed to obesity. Aerobic exercise and strength training reduce body fat and increases muscle tissue.
Why does this matter? Adipose cells (stored fat) produce inflammatory cytokines that damage tissues. Over time, inflamed tissues can develop premalignant and malignant changes and the ongoing inflammation further fuels their growth. Plus, people who are obese have higher levels of estrogen and that can fuel the growth of breast and uterine cancer.
Exercise Improves Insulin Sensitivity
Studies show that insulin and insulin-like growth factor one (IGF-1) fuel the growth of certain types of cancer, including cancers of the prostate, colon, and breast. Research finds that aerobic exercise can lower IGF-1 in people who do it consistently. Both aerobic and strength training workouts improve insulin sensitivity and lower the risk of type 2 diabetes. In turn, this may also reduce the odds of developing some types of cancer.
Research shows that people with insulin resistance and type 2 diabetes are at higher risk of cancer. In fact, a study published in Diabetes Care found that type 2 diabetics are more likely to develop cancers of the pancreas, liver, uterus, colon, rectum, breast, and bladder. Having a high circulating level of insulin, due to insulin resistance, also acts as a growth factor for cancer. Plus, people who are insulin resistant have higher levels of inflammation, another promoter of cancer.
The Bottom Line
Exercising regularly won’t guarantee that you’ll never get cancer, but it may lower your risk. Now you know some possible ways it helps. Plus, working out has so many other health benefits. Combine regular workouts, both strength and aerobic, with a nutrient-dense, whole food diet and you’ll lower your risk even further.
There’s so much you can do from a lifestyle standpoint to reduce the odds you’ll get cancer. Take advantage of the things you can control through lifestyle and, hopefully, you’ll never face a cancer diagnosis.
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- Centers for Disease Control and Prevention. “Cancers Associated with Overweight and Obesity Make up 40 percent of Cancers Diagnosed in the United States”
- Endocrinol. Effect of Low-Intensity Aerobic Exercise on Insulin-Like Growth Factor-I and Insulin-Like Growth Factor-Binding Proteins in Healthy Men. Yuichiro Nishida ,1,2 Takeshi Matsubara,3 Takuro Tobina,1 Munehiro Shindo,1 Kumpei Tokuyama,4 Keitaro Tanaka,2 and Hiroaki Tanaka1. September 2010.
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