- Question from DeborahL: Is there a difference between the effect of exercise on getting breast cancer in the first place and the effect in preventing a recurrence? I have always been physically fit and still got breast cancer but I am wondering if my continued exercise (which I would do anyway) will help prevent a recurrence.
- Answers - Miriam Nelson We do know from observational trials that there is a reduced risk of getting breast cancer in individuals who are physically active. That doesn't mean that if you are physically active, you aren't going to get breast cancer; it just means that it's a relative risk. The same is true for individuals who get breast cancer—they can reduce their risk of recurrence by being physically active. At least, that's what the data suggest at this point. By all means, you should stay physically active. You should also be eating well and taking as good care of yourself as possible.
Julie Gralow, M.D.
With respect to reducing the risk of getting breast cancer, I absolutely agree with Dr. Nelson. There is increasing evidence that we can reduce the risk, but there's no guarantee of prevention of getting it. It's possible that in your exercising you may have delayed the onset of the breast cancer. I say that because in an important study called the New York Breast Cancer Study of BRCA1 and BRCA2 gene mutations, among the patients who ultimately got cancer, those who did physical activity and maintained a good body weight in their teens and 20s had a significantly later age of diagnosis than women who reported a sedentary lifestyle in their 20s and 30s. So the exercise you did may have delayed the onset of breast cancer.
Will exercise now reduce the risk of recurrence? There is an interesting recent study just published less than nine months ago, the Nurses' Health Study, that suggested after a diagnosis of breast cancer, exercise can reduce the risk of recurrence. It looks like for women who just walk at an average pace three to four hours a week, we saw reduction in deaths from breast cancer. It's encouraging that there may even be less recurrence and death from breast cancer by exercising.
- Judith Sachs In these studies, it seemed the greatest benefit was to have a BMI (Body Mass Index) under 25. Can you talk a little about how exercise affects weight maintenance, and how it's important to get the BMI down?
Being overweight and obesity are having a major impact on so many aspects of our health. It's not just on heart disease, diabetes, arthritis, quality of life; it's also on breast cancer and cancer in general. Many people are trying to figure out what the link is. The fact that 65% of women now are overweight or obese is putting them at a much higher risk for breast cancer. The weight control is a primary concern around cancer prevention. You can't just control your weight—you don't just flip a switch. The combination of focusing on good food choices and also increasing physical activity so you get an energy balance is quite simply what you need to do.
It sounds very simple to eat better and exercise more, but we are creatures of habit. Our bodies are programmed to not lose weight because we don't want to get into starvation mode. Our bodies have a strong appetite, a love for food. With modern society, we have created an environment in which almost all of us live in a way that we expend very little energy, so we have to be conscious when we are trying to expend more energy.
Our environment is stacked against us also, with the plethora of highly palatable foods that are available. Only 30 years ago, a typical supermarket would have 1,500 food items for sale. Now it has 40,000-60,000 to choose from. It used to be a very special occasion to eat out, but now 50% of Americans eat out at least once a day. So you can see our worlds have collided to really make all of us overweight, unless we are diligent and conscientious and have a social structure of support that allows us to eat better.
When we are more active, we burn more calories, and if we eat a little bit less or even the same (which sounds easier than it is), we will lose weight. The problem is that our appetite regulation is finely attuned, so if we burn more calories we feel like eating more so we have to consciously try to not eat more when we're exercising. But there are more benefits from exercise than just increasing metabolism. When we use our muscles, we stimulate them and that increases our resting metabolism. We also increase endorphins, which gives us a better sense of well-being and makes us happier. All of these factors help with weight control. I like to say it's not rocket science, but energy balance is much MORE complicated than that! We're programmed to gain weight, not lose it.
The Ask-the-Expert Online Conference called Physical Activity and Breast Cancer featured Miriam Nelson, Ph.D., Julie Gralow, M.D., and moderator Judith Sachs answering your questions about the many issues related to physical activity and breast cancer.
Editor's Note: This conference took place in January 2006.
The materials presented in these conferences do not necessarily reflect the views of Breastcancer.org. A qualified healthcare professional should be consulted before using any therapeutic product or regimen discussed. All readers should verify all information and data before employing any therapies described here.
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