The more often you’re active and the more frequently you exercise, the more your overall physical fitness improves. As you head into breast cancer treatment, being in the best physical condition you can has been shown to improve outcomes and tolerance of treatment.

“F” cancer is a common refrain in the breast cancer community.

I’ve even been known to utter that sentiment a time or two myself.

Once, I screamed it extra loudly toward a bleacher of onlookers as I headed for the finish of a 9-mile race I ran two months after completing radiation.

The words just flew out of me. They expressed EXACTLY how I felt.

THAT particular “F” cancer is not what I’m writing about here.

I’m sharing the importance of “F” and breast cancer, but it’s NOT what you think.

Presenting The FITT Principle

There’s an unlimited variety of lists and types of principles in the world, for example, this completely disparate collection:

  • Janet Jackson’s 1986 hit “The Pleasure Principle
  • The founding principles of the United States of America
  • The 10 Principles of Intuitive Eating

So where does the FITT Principle, ummm, fit?

In the fitness world!

For the uninitiated, which is any of you who hasn’t worked in that world of fitness, the FITT Principle is a collection of variables that can be manipulated in an infinite number of ways to influence (positively OR negatively) your fitness program and level. 





Each of these components plays a role in the exercise results you get, the outcomes you experience, and the gains (and losses!) along the way.

In this post I explore “F” FREQUENCY, and cover the remaining components in Parts III, VI and V.

Why Exercise FREQUENCY (F) Is a Big Deal

Frequency and exercise are sort of like oil and vinegar.

Just like your favorite salad dressing, they tend to separate when you need them most to be together to give you the best (flavor) outcome. 

Exercise FREQUENCY is simply HOW OFTEN you engage in physical activity and/or exercise, which in turn determines your level of PHYSICAL FITNESS.

Let me clarify the difference between physical activity, exercise and fitness, as these terms describe different concepts but are often used interchangeably. (1)

  • PHYSICAL ACTIVITY – any bodily movement produced by skeletal muscles that results in energy expenditure. The energy expenditure can be measured in calories. Physical activity in daily life can be categorized into occupational, sports, conditioning, household, or other activities.
  • EXERCISE – a subset of physical activity that’s planned, structured, and repetitive, and has as a final or an intermediate objective the improvement or maintenance of physical fitness.
  • FITNESS – a set of attributes that are either health- or skill-related. The degree to which people have these attributes can be measured with specific tests.

The more often you’re active and the more frequently you exercise, the more your overall physical fitness improves. As you head into breast cancer treatment, being in the best physical condition you can has been shown to improve outcomes and tolerance of treatment. (2)

Obviously, if you have only a handful of weeks between diagnosis and the start of treatment, that won’t be enough time to drastically improve your fitness level, but you can get started and continue into and through treatment (as appropriate and tolerated) to help maintain (and in some cases improve) the level of fitness you currently have. (3)

Why It’s So Hard to Commit

When you’re first diagnosed it may feel relatively easy to set goals for how often you’ll commit to exercising. Especially now, when everything in your world has been turned on its head, you want to feel in control of SOMETHING, and diligently planning the amount of activity you’ll get allows you to do that.

Surely, exercising 7 days/week will be a piece of cake, right?

Caution: just like before your diagnosis, SETTING exercise goals and KEEPING exercise goals are two different things.

Layer on doctor appointments, on-going tests and scans, working (or not) and managing a household, plus the million other things that make up your regular life, and the best laid plans to exercise can quickly fall by the wayside. Meeting that exercise goal begins to feel like one more obligation in a schedule with no room for anything extra, and before you know it? Bye-bye exercise.

Why You Need to Suck It Up And Commit Anyway

The reason behind the term “secret weapon” in the title of this series is because in my opinion (which is anecdotal but also backed by research,) exercise truly is.

Especially now, post-diagnosis and heading into the throes of treatment, I strongly encourage you to make exercise a non-negotiable priority and an integral part of your treatment plan.

Before you start treatment there’s nothing to prevent you from using the “frequency of exercise guidelines for the general healthy adult public” recommended by the World Health Organization (WHO); at least 150 minutes of moderate-intensity aerobic physical activity, or 75 minutes of vigorous-intensity aerobic physical per week. (4) 

If your level of physical conditioning supports it, even once you begin treatment there’s no reason NOT to follow those same guidelines, or to continue engaging in exercise at the frequency you did before your diagnosis; just check in with your body (and your doc for good measure) and do what you can safely tolerate. (5)

Once you start treatment there are certain side effects (like fatigue), as well as muscle loss and a decrease in cardiorespiratory fitness that can be minimized or eliminated with exercise. One particular study of 204 breast cancer patients undergoing chemotherapy suggested that beginning an exercise program as early as within six weeks of diagnosis can have positive effects on each of those areas of concern. (6)

Keep in mind the WHO guidelines are not disease-specific, rather, they support overall health and potential risk reduction of several diseases, including cancer.

I know what you’re thinking; “A hell of a lot of good that does me NOW.”

Please know that maintaining an optimal level of fitness throughout treatment supports overall health as you move into survivorship. Rebuilding from your current (or close to it – treatment may temporarily cause it to slip somewhat) level of fitness when treatment ends takes much less effort than starting back from scratch. 

Because it’s not yet clear whether the most benefit comes from a single session of exercise all at once (for example doing 30 consecutive minutes), or by engaging in smaller blocks of time throughout the day, aim to hit the recommended 150 minutes per week in whatever way assures you can accomplish it.  

Where Exercise “F” Fits Along The Breast Cancer Continuum

Whether you’ve started treatment, moved into survivorship, or are living with metastatic breast cancer, your focus now is on reducing risk of recurrence or morbidity.

How much exercise is enough to offer protection, what happens if you stop, and how long do you need to exercise BEFORE it “works?”

  • Consistent evidence links physical activity after a diagnosis with better breast cancer outcomes. (7)
  • An average of ~40-50% lower risk of recurrence is associated with 3-5 hours per week of moderate exercise. (7)
  • Currently, guidelines for exercise frequency in the breast cancer population are the same as for general population; 150 minutes of moderate-intensity, 75 minutes of vigorous-intensity exercise PER WEEK.
  • One study compared changes in frequency of exercise over time between women who started exercising at the start of chemotherapy vs those who started exercising at the completion of chemotherapy, determining that women can sustain exercise frequency for the duration of chemotherapy treatment. Obviously there is a highly individual response to chemotherapy, but the study results are encouraging for women determined to maintain a pre-diagnosis fitness program. (8)
  • Researchers and/or doctors aren’t certain how long a woman must exercise before the risk-reducing benefits “kick in”; likewise, they’re not certain how long those benefits last after she stops exercising, yet one French study of postmenopausal women suggests the following: (9, 10)
    • Women with recent (within the previous 4 years) recreational levels ≥12 metabolic equivalent task hours – the equivalent of walking ~ 4 hours per week, or cycling or doing more intense exercise 2 hours per week – had a lower risk of invasive breast cancer than women with lower levels. This study also found that postmenopausal women who had exercised regularly between 5 and 9 years earlier, but were less active in the past 4 years didn’t have a lower risk of breast cancer.” 
    • When women stopped exercising, the risk-reducing benefits quickly disappeared. 

What You Can Do NOW

  • Use the 150 minutes PER WEEK guideline in a way that supports your personal fitness goals and individual fitness level. 
  • Consistency helps establish a habit of exercise. For example, 20 minutes of exercise three days per week – EVERY WEEK – confers more health benefits and establishes the exercise habit more effectively then going long stretches of time between bouts of exercise. 
  • To encourage consistency, set a minimum baseline for the number of days you’ll realistically exercise. For example, if you set a minimum baseline of seven days/week and you do less than that you’ll feel BAD. Exercise is supposed to make you feel better, not worse, so set a realistic number (3?), increasing it over time if you can. 

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  1. Physical activity, exercise, and physical fitness: definitions and distinctions for health-related research.
  2. The Case for Prehabilitation Prior to Breast Cancer Treatment.
  3. Better Sooner and Later: Prehabilitation
  4. Global Recommendations on Physical Activity for Health
  5. Effects of exercise on breast cancer patients and survivors: a systematic review and meta-analysis
  6. Effects of an 18-week exercise programme started early during breast cancer treatment: a randomised controlled trial.
  7. Physical Activity and Cancer FACT Sheet
  8. Timing and Sustainability of an Exercise Intervention in Women With Breast Cancer During and After Cancer Treatment
  9. Recent Recreational Physical Activity and Breast Cancer Risk in Postmenopausal Women in the E3N Cohort
  10. Exercise Reduces Risk, but Benefits Disappear if Women Stop Exercising