Breast cancer is the most frequently diagnosed cancer and the second leading cause of cancer related deaths among women in the United States. The steady increase in the number of patients diagnosed with breast cancer has been attributed to lifestyle changes that have taken place since the 1980s, including increased use of alcohol and tobacco, high-fat and high-sugar diets, women opting to not have children or to delay pregnancy, and low levels of physical activity. Regular physical activity and maintaining a healthy weight have been associated with a lower risk of developing multiple chronic diseases and 13 different types of cancer, including breast cancer. Studies have shown that women who get regular physical activity have lower risk of developing breast cancer than women who do not exercise.
The link between physical activity and breast cancer
Physical activity can lower the risk of developing breast cancer in numerous ways:
- Regulating hormones: Normal hormone functioning in women involves the production and regulation of hormones such as estrogen and progesterone, which change throughout the menstrual cycle. Hormone functioning also changes significantly with age, especially during puberty, pregnancy and menopause. Higher levels of some hormones like estrogen and progesterone and lower levels of others can lead to breast cancer. Physical activity helps regulate hormones in the body and prevent breast cancer.
- Maintaining a healthy weight: Being overweight increases the risk of breast cancer significantly, especially in women who have gone through menopause. Some studies have shown that an elevated body mass index (BMI) is related to breast cancer risk. Additionally, obese women who have gone through menopause are at high risk of developing some types of breast cancer because of higher levels of insulin and estrogen. While BMI is a more traditional way to define a healthy weight, clinicians are also using other ways to assess weight in patients. Body composition (ratio of fat to lean muscle), overall physical activity and waist circumference are other ways to define a healthy weight.
- Improving immune function: Regular physical activity helps boost the immune system, improving the body’s ability to fight off cancer cells and prevent tumor development. Exercise improves the immune system by mobilizing the immune cells already in circulation and strengthening the body’s ability to identify and destroy cancer cells.
- Reducing chronic inflammation: Inflammation is thought to be a key factor in the growth of breast cancer because it encourages the cancer cells to grow and helps create an environment that encourages them to keep growing. Regular physical activity may slow down age-related weight gain. It may also reduce chronic inflammation, levels of body fat and other factors that support the ongoing inflammatory process.
Incorporating regular physical activity into your daily routine
Intense exercise is not necessary to live a healthy life and an active lifestyle. It starts with a short walk or cycling session with friends. There are even exercises that can be done while sitting in a chair, if necessary. The American Cancer Society recommends getting at least 2.5 hours of moderate physical activity per week, or 1-2 hours of vigorous activity per week. Small steps can also have big impact. For example, taking the stairs instead of the elevator or parking your car further in a parking lot and walking to the door may benefit your health in the long term. If you are new to exercising and want to increase your physical activity levels, here are some tips: