By Pat Carragher - August 22, 2023
A new study out of Sweden is the latest to support that being in good physical shape can significantly reduce cancer risk. The study, published in the British Journal of Sports Medicine, found that men with high levels of cardiorespiratory fitness in their teens and 20s had a lower risk of developing nine forms of cancer decades later.
⚠️ Is there an association between cardiorespiratory fitness in youth and the incidence of site-specific cancer?— British Journal of Sports Medicine (BJSM) (@BJSM_BMJ) August 17, 2023
NEW #OriginalResearch in 1,078,000 men suggests that CRF is linearly associated with a lower hazard of developing most cancers 📉 🏃♂️
👉 https://t.co/KJhatikb3D pic.twitter.com/FOFhkIJf1Y
The study looked at more than 1 million men between the ages of 16-25 over an average of 33 years. Participants underwent a baseline military test to determine their fitness level. The tests included riding a stationary bike at a low resistance for five minutes, then a steady increase until the men were too tired to continue. Researchers then evaluated the rates of cancer diagnoses compared to the participants’ fitness levels.
They found that those with high fitness levels had a 19% lower risk of head and neck cancer and a 20% lower risk of kidney cancer compared to the low fitness group. The risk of lung cancer was 42% lower for the fittest participants. The study’s authors noted that smoking was believed to be a contributing factor in fitness level.
“Having higher cardiorespiratory fitness is related to the same benefits that result from engaging in more physical activity: better immune function, regulating metabolism and decreasing chronic inflammation,” said Dr. Nathan Parker, a researcher in the Department of Health Outcomes and Behavior at Moffitt Cancer Center. “All of these benefits tend to help reduce cancer risk and improve trajectories following cancer diagnosis.”
According to Parker, cardiorespiratory fitness is a measure of how well the body’s respiratory and circulatory systems can supply oxygen to working skeletal muscle to sustain high-intensity physical activity over time. It’s an objective measure of an individual’s physical activity level and tends to improve with more frequent, longer duration and higher intensity aerobic exercise.
Aerobic exercise performed at moderate to vigorous intensities generally has the largest impact on cardiorespiratory fitness. Those exercises include brisk walking, jogging or running, cycling, swimming, aerobics, and playing sports that involve sustained movement. Resistance training to improve muscular strength and function can also lead to cardiorespiratory fitness benefits.
In addition to head and neck, kidney and lung cancer, the study showed that the risk for high-fitness participants was nearly 40% lower for esophageal, liver, bile duct and gallbladder cancer, and 20% lower for stomach and colon cancer.
While this study focused on men, Parker says women who improve their cardiorespiratory fitness levels can experience the same benefits. A 2019 study analyzed nearly 190 women and found that higher levels of cardiorespiratory fitness were associated with as much as a 20% lower risk of cancer incidence and 26% reduction in cancer deaths.