High Intensity Exercise Reduces Growth of Malignant Cells in Colon
You may sometimes hear the terms colon cancer and colorectal cancer used interchangeably. However, they are different. Colorectal cancer includes cancers occurring in the colon and rectum, while colon cancer occurs only in the large intestines.
Historically, colon cancer has been confined to those over the age of 50, but this is changing. According to a recent report1 by the American Cancer Society, prevalence2 among younger adults is rising.3 As reported by STAT News:4
“Among adults between the ages of 20 and 39, colon cancer has increased by 1 percent to 2.4 percent a year since the mid-1980s. This rise has been so dramatic that those born in 1990 and afterward have rates of colon cancer not seen since 1890.”
Your Colon Is Integral to Digestion
There are four anatomical parts to the colon: the descending colon, ascending colon, transverse colon and sigmoid colon. Although the small intestines play a major role in absorbing nutrients, the function of the large intestines is to store waste, reclaim water and absorb certain vitamins, such as vitamin K.
In some cases, the colon is called the large bowel and it plays an important role in how your body utilizes the food you eat.5 Digestion begins in your mouth, where the food is chewed into smaller pieces and moved to the back of your throat. After swallowing, the food bolus travels through the esophagus and into your stomach.
Inside your stomach, gastric juices break down food and powerful muscles churn it until it’s a creamy liquid.6 As it moves into your small bowel, or small intestines, the particles get even smaller and juices from the pancreas, liver and gallbladder are mixed with the liquid to aid in digestion.
The food travels nearly 20 feet through the small intestine until it reaches your colon. As it arrives, it’s mostly liquid. The large intestine absorbs water and bacteria break down the remaining material, before being stored in the rectum and excreted during a bowel movement.
High Intensity Exercise Reduces Growth of Colon Cancer Cells
I am a big supporter of exercise, especially high-intensity interval training (HIIT). Recent research published in the Journal of Physiology7 found high intensity activity was associated with a reduction in mortality among those who survived colorectal cancer.
Past research had demonstrated exercise over a long period of time may help prevent cancer, but the results of this new study suggests even short bursts may have a positive effect.8 The team was interested in the mechanism behind this effect.
Individuals with colorectal cancer were recruited for the study and asked to complete either an acute session of HIIT or 12 sessions of HIIT over a four-week period. The researchers collected blood samples from the participants in the group who completed an acute session before, immediately after finishing the session and at 120 minutes after the workout.
In the group that completed four weeks of HIIT, the researchers collected blood samples before and then at the end of four weeks. The blood was then added to a petri dish with human colorectal cancer cells. They reported the blood sample drawn immediately following exercise reduced the number of colon cancer cells in the dish.9
They also found a significant increase in cytokine-signaling proteins responsible for modulating the immune and inflammatory responses, which may have been triggered by a transitory inflammatory response after intense exercise.10 Lead author, James Devin, Ph.D., commented on the results:11
“We have shown that exercise may play a role in inhibiting the growth of colon cancer cells. After an acute bout of HIIT there were specific increases in inflammation immediately after exercise, which are hypothesized to be involved in reducing the number of cancer cells.
This suggests that a physically active lifestyle may be important in tackling human colorectal tumors. We would now like to look at how these changes in growth occur and understand the mechanisms by which biomarkers in the blood can impact cell growth.”
Colon Cancer Kills 51,000
Colorectal cancer is the second leading cause of cancer death in men and women in the U.S., with an estimated 140,250 new cases diagnosed12 and 51,020 deaths13 in 2019. The American Cancer Society14 estimates the lifetime risk is about 1 in 22 for men and 1 in 24 for women.
According to the World Cancer Research Fund from the American Institute for Cancer Research, colorectal cancer is one of the clearest markers of nutritional transition, increasing in countries undergoing rapid societal and economic changes.15 According to Fight Colorectal Cancer, 60% of colorectal cancer deaths could have been prevented with screening and 25% diagnosed have a family history of the disease.16
While the exact cause for colon cancer has never been pinpointed to one factor, researchers have identified several that can increase your risk of developing colon cancer. Data show a familial history influences your risk, especially in combination with environmental factors.17
Data have also demonstrated African-Americans have a higher incidence of colorectal cancer, as do Ashkenazi Jews. Lifestyle factors may also increase your risk, including a diet high in red and processed meats, an inactive lifestyle, smoking, heavy alcohol use and obesity.
Those who have a history of inflammatory bowel disease, history of colorectal cancer or polyps and Type 2 diabetes may also suffer an increased risk of colorectal cancer.18
Antibiotics May Influence Your Risk of Colon Cancer
Antibiotics not only fundamentally alter your gut microbiome, bacteria requiring antibiotic treatment may also be inflammatory. Research shows this is yet another risk factor for colon cancer development. This study19 was not the first time antibiotics were implicated in a higher risk of colorectal cancer.20
Symptoms of colorectal cancer include a persistent change in your bowel pattern, such as diarrhea or constipation. You may find a change in the consistency of your stool or you may notice blood in your stool. However, blood in the stool is not always red, depending upon the location of the bleeding in your colon.
The higher in your colon the bleeding occurs, the more likely the blood will be a darker black color, potentially blending with your stool if there is a small amount. You may experience persistent abdominal discomfort, such as cramps, gas or pain not relieved over time.21
Weakness, fatigue and unexplained weight loss are other symptoms of colorectal cancer. Some may experience no symptoms at all in the early stages of the disease. When the symptoms appear will depend upon the size of the cancer and its location in your large intestines.
Benefits of Exercise Include More Than Cancer Prevention
Close to 80% of U.S. adults do not get enough exercise, according to a survey conducted by the U.S. Centers for Disease Control and Prevention (CDC).22,23 Only 20% were getting the recommended amount, which includes 2.5 hours of moderate-intensity aerobic exercise and strength training activities twice a week.
While the featured study demonstrates the benefits of HIIT against the proliferation of colon cancer cells, exercise holds a plethora of other benefits. In fact, exercise may be the key to a longer life. A study published in the European Journal of Preventive Cardiology24 sought to estimate age based on performance during a stress test.
Researchers discovered the risk of death could be cut by 17% by replacing 30 minutes of sitting with low intensity exercise, such as walking.25,26 Replacing 30 minutes with moderate to vigorous exercise cut the risk by 35%. Exercise has also been linked to lower rates of depression and Alzheimer’s disease, along with improved memory.27
In fact, exercise appears to be key for the successful treatment of depression or anxiety.28 Those who exercise experience feeling happier, potentially from a boost in serotonin, dopamine and norepinephrine.29 Exercise slows the aging process,30 improves your skin31 and may help you recover faster from chronic disease. For instance, exercise has benefited those with joint pain, including osteoarthritis.32 Another benefit of consistent HIIT is improved fat burning and weight loss.
Gut Microbiome Aids in Colon Health
Your gut microbiome also plays a role in the treatment and prevention of colorectal cancer. Researchers found Lactobacillus reuteri has the potential to treat colon cancer tumors.33 Other studies targeting colorectal cancer have determined there are several factors that increase the incidence of colorectal cancer, including diagnosis with inflammatory bowel disease.
Your gut microbiome is a large player in your overall health, including the development of colorectal cancer. In one study,34 researchers used positron emission tomography to scan for tumors in mice. They found fewer and smaller tumors in those treated with probiotics in comparison with mice who were treated with placebos.
Researchers35 found experimental evidence highlighting the key role played by intestinal microbiota in malignant gastrointestinal diseases. In another,36 data showed microbiota may promote homeostasis and antitumor responses in the intestines. In a third review,37 scientists examined current research and focused on bacterial pathogenesis, proposing evidence of an association with colorectal cancer.
There Is More Than One Reason for Blood In Your Stool
Colorectal cancer is only one reason there may be blood in your stool. Although it may be frightening and signal a serious problem, it doesn’t always. Blood in your stool means there is bleeding in your digestive tract originating some place between your esophagus and your rectum.
If the blood is bright red it signals the bleeding is happening in your rectum or around your anus. At other times the blood may have been digested in the intestines, making your stool appear black, like coffee grounds. Possible causes of blood in your stool include:
| Diverticular disease — These are small pouches projecting from the colon wall, which don’t usually cause problems but sometimes bleed or become infected. |
| Hemorrhoids — These are swollen veins in the lowest part of your rectum and anus and are sometimes called piles.38 Hemorrhoids are one of the most common causes of rectal bleeding as the vein is sometimes stretched so thin they get irritated, causing them to crack and bleed. They are rarely dangerous and often clear in a couple of weeks. However, you may want to consult with your physician to ensure it’s not a more serious condition. |
| Anal fissure — This is a small cut or tear in the tissue lining the anus, similar in appearance to cracks on chapped lips or a paper cut. Fissures may happen when passing large hard stool. |
| Angiodysplasia — This is a condition in which your blood vessels are fragile and may lead to bleeding. |
| Peptic ulcers — Peptic ulcers may occur in the stomach or upper end of the small intestines. Caused by an infection with Helicobacter pylori, they may cause open bleeding areas. Long term use of anti-inflammatory drugs such as aspirin, ibuprofen or naproxen may also cause ulcers. |
| Polyps or cancer — Polyps are benign growths, which sometimes become cancerous. Both polyps and colorectal cancer may cause bleeding not seen with the naked eye. |
| Gastroenteritis — This is an infection in your stomach, often presenting with runny stools, containing mucus and traces of blood. It may result from a virus, bacteria or food poisoning, and while the main symptom is diarrhea it may also include vomiting, stomach pain and dehydration. |
| Inflammatory bowel disease (IBD) — The two main forms of IBD are Crohn’s disease and ulcerative colitis. The condition is not the same as irritable bowel syndrome. It’s a chronic condition responsible for inflaming the intestinal walls, often resulting in diarrhea, pain and weight loss. |
Reduce Your Risk of Colon Cancer
The health of your gut affects your entire body, which is why protecting your colon health shares many of the same principles as protecting your gut health. Fiber and probiotics in fermented foods all play vital roles in disease prevention and promoting a strong, healthy gut microbiome. For more information, see my previous article, “Gut Microbiome May Be a Game-Changer for Cancer Prevention and Treatment.”
While your microbiome is important, there are several other simple strategies you may use to reduce your risk of colorectal cancer. For more information see my previous article, “Antibiotics Increase Bowel Cancer Rates.”