January 11, 2023

From BS&W: How Exercise Affects Breast Cancer

Written by: Dr. Vaishali Kent

Dr. Kent Vaishali

Before we talk about how exercise affects breast cancer, let’s define exactly what breast cancer is. Cancer is a type of disease that causes a normal cell in the body to change and grow uncontrollably. This is caused by damage to the DNA. 

Although the precise cause of breast cancer is unclear, breast cancer occurs when these changes happen to a breast cell. Cancer is generally hereditary, familial, or sporadic. True hereditary breast cancer is rare to acquire and is caused by an offspring inheriting a mutation or DNA damage from a parent. Familial cancers are breast cancers that are not due to identifiable mutations, but are instead commonly attributed to shared environments or lifestyles of families. The majority of breast cancers are sporadic; these cancers are due to an accumulation of your personal genetic makeup, exposures, and environment throughout your life. These are typically referred to as “risk factors.”

A risk factor is anything that makes you more likely to get breast cancer. Some risk factors are controllable, while others are uncontrollable. Some examples of controllable risk factors are:

  • Obesity
  • Diet
  • Physical Inactivity
  • Exercise

So how exactly does exercise reduce the risk of breast cancer?

  • 20% of all cancers diagnosed in the US relate to being overweight, increased alcohol intake, inactivity, or poor nutrition.
  • Some studies demonstrated a decrease in disease free and overall survival in obese women with breast cancer.
  • Obesity is associated with more advanced stages at diagnosis.
  • There is an increase in complications in obese women who undergo breast cancer treatment.

Exercise can reduce adiposity and associated risk factors.

  • Risk factor markers such as estrogen, insulin, and inflammatory markers can decrease with exercise.
  • Exercise can increase molecules with anti-inflammatory properties.
  • Some studies demonstrate as much as a 20–40% decrease in the risk of developing breast cancer with exercise.

If you are diagnosed with breast cancer, exercise still helps!

  • Exercise can improve breast cancer recurrence.
  • Exercise can improve survival with breast cancer.
  • Exercise can reduce side effects of treatments.
  • Studies suggest that exercise during chemotherapy might improve treatment efficacy.

Specifically, the American Cancer Society recommends:

  • 150–300 minutes of moderate intensity or 75–150 minutes of vigorous intensity activity a week
  • Achieving or exceeding 300 minutes is most ideal
  • Children and teens should get at least one hour of moderate or vigorous intensity activity each day
  • Limiting the time spent sitting
  • Achieving and maintaining a healthy weight throughout your life

Women who perform 300 minutes of exercise per week have a much larger reduction of body fat than those who do not meet 300 minutes. This means even a couple of weekly runs and workouts have a significant chance in improving your health, specifically against breast cancer. Although any form of exercise is helpful, studies show that the intensity of the workout does matter. Try switching up your walks to jogs or runs. 

Baylor Scott & White Health offers various resources to help with your exercise goals and to aid in your breast cancer journey. Specifically, BSWH offers specialized exercise programs, yoga, and relaxation techniques. To learn more about our Joan Katz Cancer Resource Center and the resources it offers, please visit the JKCRC website here.