We have long known that regular exercise can prevent cardiovascular disease, and is good for one’s bones, balance, and brain. For the past 20 years, however, evidence has been accumulating that exercise can prevent and mitigate many cancers. The list of potentially preventable cancer types has been growing, including many that were heretofore unsuspected.
In 2003, a paper in the journal Medicine & Science in Sports & Exercise reported that more than a hundred population (epidemiologic) studies on the role of physical activity and cancer prevention have been published. The authors noted that:
“The data are clear in showing that physically active men and women have about a 30-40 percent reduction in the risk of developing colon cancer, compared with inactive persons … With regard to breast cancer, there is reasonably clear evidence that physically active women have about a 20-30 percent reduction in risk, compared with inactive women. It also appears that 30-60 min/day of moderate- to vigorous-intensity physical activity is needed to decrease the risk of breast cancer, and that there is likely a dose-response relation.”
These studies were collected mainly by questionnaires about exercise regularity and subsequent development of cancers. Although this type of information is convincing, we now have even more conclusive results derived from careful assessment of physical fitness and subsequent development of cancer, at least in men.
According to a 20-year, prospective study of more than 17,000 men at the Cooper Institute in Dallas, Texas, measured levels of fitness appear to be as predictive of cancer risk and survival as they are of heart disease risk and survival. Their data showed that the risks of lung and colorectal cancer were reduced 68% and 38%, respectively, in men with the highest level of fitness, compared with those who were the least fit.
Although good fitness did not significantly reduce prostate cancer incidence, the risk of dying was significantly lower among men with an already present prostate, lung, or colorectal cancer, provided they were more fit in middle age.
Although prior studies have shown that being physically active is protective against cancer, this study is unique because it looked at a very specific marker – cardio-respiratory fitness as measured by maximal exercise tolerance testing.
What was unexpected was that evidence of fitness not only predicts prevention of cancer but also even mortality after cancer has already been diagnosed or treated.
The 17,049 men in the study underwent exercise tolerance testing with a treadmill or bicycle and risk factor assessment at an average age of 50 years as part of a long-term study. Metabolic equivalents (METs) were used to record the men’s cardio-respiratory fitness (CRF) and to place them into five CRF quintiles. Lung, colorectal and prostate cancers were assessed using Medicare claims data at Medicare age, and cause-specific mortality was determined after cancer diagnosis.
Over the 20 years of follow-up, 2,885 men had been diagnosed with prostate, lung, or colorectal cancer, and of these, 769 died.
Compared with men in the lowest CRF fitness quintile, hazard ratios for developing lung and colorectal cancer men in the highest fitness group were 68% lower for lung cancer and 32% lower for colorectal cancer, after researchers adjusted for such risk factors as smoking, body mass index, and age. In men who had already developed all these cancers, mortality also declined across the higher the fitness groups. Even a modest increase in fitness reduced the risk of dying from cancer and cardiovascular disease by 14% and 23%, respectively.
Another striking finding is that even in those men aren’t obese, if they aren’t fit they still have an increased risk of cancer, suggesting that everyone—regardless of weight—can benefit from improving their fitness.
The study did not evaluate whether a particular type of exercise contributed more consistently to cardiovascular fitness, but in general, activities performed at high intensity, regardless of type, are the best way to improve fitness.
Extending our knowledge further, a large recent study confirmed that exercise lowers the risk of additional types of cancer, and now it shows just how much the reduction is for each type. The study was of 1.4 million people carried over 11 years and disclosed that people who exercised the most had a significant reduction of risk for many. They found the following:
Those exercising the most versus the least had the percentage risk reductions for cancers in the following locations:
TYPE OF CANCER % REDUCTION
- Esophagus 42%
- Liver 27%
- Lung 26%
- Kidney 23%
- Stomach 22%
- Uterus (Endometrium) 21%
- Myeloid Leukemia 20%
- Myeloma 17%
- Colon 16%
- Head and Neck 15%
- Rectum 13%
- Bladder 13%
- Breast 10%
Although additional research will be needed to quantify exactly how much exercise will prevent each cancer, the message is becoming progressively clearer: Plenty of exercise is fit for all, and probably the more the better!
EXERCISE EVEN BENEFITS THOSE UNDERGOING CANCER TREATMENT
A recent study found that physical activity can also mitigate some side effects of cancer treatment, such as brain fog and heart and nerve damage. While prior research had shown that exercise can be generally helpful during cancer treatment, this study went a step further and systematically analyzed data from randomized controlled trial results published between 2012 and 2024. The takeaway: Exercise (e.g., high-intensity and interval training) not only reduced adverse effects often associated with cancer and its treatment, but also improved psychological well-being, body composition, and overall quality of life.
The researchers concluded that their study reinforces the efficacy of incorporating exercise into all cancer treatment protocols. Of course, every cancer patient has their own journey and limitations, so there’s no one-size-fits-all workout plan.
Below is a link to access my books available for purchase (digital or print versions):
Website: https://radiantmortontavel.com/
To be placed on the mailing list for future blogs, contact: tavelmorton@gmail.com