Being fit earlier in life has been associated with a reduced risk of developing various types of cancer later on, according to a large long-term study. The study, published in the British Journal of Sports Medicine, analyzed data from over 1 million male Swedish conscripts aged 16 to 25 who were followed for an average of 33 years. The results indicated that good cardiorespiratory fitness, which refers to an individual’s ability to engage in sustained aerobic exercises like running, cycling, and swimming, was linked to a 42% lower risk of lung cancer, a 40% lower risk of liver cancer, and a 39% lower risk of esophageal cancer. Additionally, higher cardiorespiratory fitness was associated with a lower risk of head and neck, stomach, pancreatic, bowel, and kidney cancers.
However, the study did find a few unexpected results. Higher cardiorespiratory fitness was associated with a 7% increased risk of prostate cancer and a 31% increased risk of skin cancer. The researchers believe that these findings may be influenced by more frequent prostate cancer screening and greater sunlight exposure in individuals with high fitness levels.
While the study did not fully account for the effects of diet, alcohol, and smoking on cancer risk, the results are still compelling. Dr. Claire Knight, senior health information manager at Cancer Research UK, points out that exercise alone is not enough to prevent cancer and that factors like diet and lifestyle habits also play a significant role.
Dr. Mark Hamer, a professor of sport and exercise medicine at University College London, believes that these findings support the promotion of interventions aimed at increasing cardiorespiratory fitness in youth during their school and university years.
It’s worth noting that this study relied on observation and cannot establish a cause-and-effect relationship between fitness and cancer risk. Nonetheless, the long-term follow-up period of the study helps alleviate concerns about reverse causation, where existing illness leads to poor fitness and early death. The results also suggest that aerobic activities like running, biking, and swimming may be more strongly associated with cancer risk reduction than resistance training.
Reducing the risk of cancer is just one of many benefits of exercise. Onerup emphasizes that any physical activity is better than none and that more physical activity leads to better health outcomes. To maintain optimal health, Dr. Knight recommends aiming for 150 minutes of exercise per week, although gradually building up activity over time is also effective.
Ultimately, this study highlights the importance of leading an active lifestyle for overall health and underscores the need for further research to better understand the relationship between fitness and cancer risk.
