- Moderate and high cardiorespiratory fitness is associated with a lower incidence of certain cancers in men, according to a new Swedish study.
- The study’s authors found a solid association between this type of fitness and a reduction in mortality for colon and prostate cancer, as well as for lung cancer for people over 60.
- The positive link between cardiorespiratory fitness and young non-smokers was especially significant.
A large new study from Sweden finds that cardiorespiratory fitness is associated with a lower risk of dying from colon, lung, and prostate cancer.
Cardiorespiratory fitness, or CRF, refers to the ability to perform whole-body, large muscle exercise of moderate- to high-intensity for extended periods of time. Such activities involve one’s cardiovascular and respiratory systems.
The study’s findings are a bit complicated in that cardiorespiratory fitness was linked to a decrease in the risk of developing colon and lung cancer but an increase in the risk of developing prostate cancer. Even so, it was associated with a lower risk of mortality from all three cancers.
The team, led by researchers from the Swedish School of Sport and Health Sciences, analyzed Swedish health service data from 1982 to 2019 for 177, 709 men who were followed for an average of 9.6 years. Their mean age was 42, and they had an average body mass index (BMI) of 26.
The researchers assessed the individuals’ health according to a range of factors, including body mass and height, their habits, lifestyle, and self-reported health, with each participant partaking in an in-depth interview with a health service coach.
In addition, each individual had taken a submaximal cycle ergometer test to assess and rate their degree of cardiorespiratory fitness.
The study is published in JAMA Network.
Higher fitness, lower mortality risk
In the overall group, cardiorespiratory fitness was associated with a 2% lower risk of colon and lung cancer and a 1% increase in the incidence of prostate cancer. It was also linked to a 2% lower risk of dying from colon cancer, a 3% lower risk of lung cancer mortality, and a 5% reduction in the chances of dying from prostate cancer.
The researchers found that the reduction in cancer incidence and mortality was even greater when they focused on younger, non-smokers who had healthy BMIs and higher cardiorespiratory fitness.
Cardiorespiratory fitness was associated with a lower lung cancer risk; however, after adjusting the results to the age of the participants, cardiorespiratory fitness was associated with a lower lung cancer incidence and death only in people ages 60 years or older.
“The general implication is that cardiorespiratory fitness is a strong and independent risk factor for cancer mortality. Promoting a higher level of fitness can prevent dying from these cancers,” said Dr. Xuemei Sui, associate professor in exercise science at the Arnold School of Public Health of the University of South Carolina, who was not involved in the study.
The association remained strong even when the researchers adjusted for a range of factors known to affect cancer risk.
“After adjusting these risk factors, [cardiorespiratory fitness] is still significantly associated with the cancer outcomes. This is telling us that the beneficial effect of CRF on cancer is independent of education, diet, smoking, and comorbidity,” said Dr. Sui.
“Just like smoking cessation, we should promote improving CRF to prevent dying from these cancers,” she added.
“At least 25% of cancer cases are felt to be due to excess weight and a sedentary lifestyle,” said Dr. Suresh Nair, hematology specialist, physician in chief at Lehigh Valley Topper Cancer Institute, who was also not involved in the study.
“Physical activity may decrease risk factors for various cancers by several mechanisms, including decreasing metabolic hormones such as insulin growth factor, decreasing inflammation which can lead to cancer, and improving immune function, which can prevent cancer,” said Dr. Sui.
She noted that genetics plays a secondary, less influential role in one’s cardiorespiratory fitness.
“Cardiorespiratory fitness is an objective marker of an individual’s regular physical activity.”
— Dr. Xuemei Sui
Why cardiorespiratory fitness may prevent lung cancer in older adults
Dr. Sui hypothesized that the stronger effect of cardiorespiratory fitness in older adults may have to do with their activity levels, saying, “I think for people over 60, compared to those younger than 60, they might benefit more from the lifelong active lifestyle.”
“Further, younger people might be more diverse, and other risk factors might have stronger influence on cancer outcomes than cardiorespiratory fitness,” compared to people over 60, she said.
In addition to reducing the risk of some cancers, cardiorespiratory health is associated with a variety of health benefits:
- increasing longevity and improving one’s quality of life
- strengthening the heart and lungs
- improving blood pressure and cholesterol levels
- reducing the risk of cardiovascular diseases
- improving cognitive function
- providing feelings of emotional well-being
“This study adds to growing evidence of the connection between fitness and decreasing risk of cancer. Physicians need to recognize and counsel patients about cardiorespiratory fitness as a modifiable risk factor for cancer.”
— Dr. Suresh Nair
The key to cardiorespiratory fitness is aerobic exercise that increases the amount of oxygen you can breathe in.
The American Heart Association recommends everyone get 150 minutes of moderate aerobic exercise weekly, or 75 minutes of vigorous aerobic exercise, or a combination of both. Ideally, this exercise should be spread throughout the week.
Always consult your physician before embarking on an exercise program of any kind.
Typical, easy-to-do aerobic exercises include walking briskly, dancing, riding a bicycle, climbing stairs, swimming, jogging, and jumping rope. One might also try jumping jacks, burpees, running planks, and side-shuffle touches.
There are also more intense cardiorespiratory fitness exercises, such as sprint interval training and high-intensity interval training.