By Dr. Mercola
Breast cancer is a growing epidemic among women, with just under 12 percent of women developing an invasive form of the disease during their lifetimes.
This works out to about one in eight U.S. women!
Research suggests, however, that one of the most powerful ways to lower this risk substantially is through the simple act of exercise.
New research is underway to determine just how much exercise -- either 150 minutes or 300 minutes a week -- is best for cancer prevention, but it's safe to say that starting an exercise regimen, if you're not already participating in one, is a very wise strategy to optimize your health.
Exercise May Reduce Your Breast Cancer Risk by Up to 40 Percent
The notion that exercise may help prevent cancer dates back to 1922, when two independent studies observed that cancer deaths declined among men working occupations that required higher amounts of physical activity.
It wasn't until the 1980s that the topic received due attention once again, and since then a paper in the journal Medicine & Science in Sports & Exercise reported that "more than a hundred epidemiologic studies on the role of physical activity and cancer prevention have been published."
In the same paper, which reviewed published epidemiologic studies on physical activity and the risk of developing cancer, it's noted that:
"The data are clear in showing that physically active men and women have about a 30-40% reduction in the risk of developing colon cancer, compared with inactive persons … With regard to breast cancer, there is reasonably clear evidence that physically active women have about a 20-30% reduction in risk, compared with inactive women. It also appears that 30-60 min·d-1 of moderate- to vigorous-intensity physical activity is needed to decrease the risk of breast cancer, and that there is likely a dose-response relation."
More recently, two other studies echoed this finding:
- Women who were active at home during the day, engaging in heavy lifting or carrying rather than mostly sitting, had a 38 percent reduced risk of invasive breast cancer
- Strenuous activity in teens and moderate activity after menopause also lead to a reduction in breast cancer risk
Why Might Exercise be Useful for Cancer Prevention?
One of the primary reasons exercise works to lower your cancer risk is because it drives your insulin levels down. Controlling insulin levels is one of the most powerful ways to reduce your cancer risk. It's also been suggested that apoptosis (programmed cell death) is triggered by exercise, causing cancer cells to die. Exercise also improves the circulation of immune cells in your blood. The job of these cells is to neutralize pathogens throughout your body, as well as destroying precancerous cells before they become cancerous..
The better these cells circulate, the more efficient your immune system is at defending itself against infections and diseases like cancer.
Unfortunately, many public health guidelines still focus only on the aerobic aspects of exercise, and this exclusive focus can lead to imbalances that may actually prevent optimal health. This is why it's so important to maintain a well-balanced fitness regimen, that includes not just aerobics, but also strength training, stretching, and most importantly, high-intensity interval training (which I'll discuss shortly).
Additionally, according to a 2000 study published in the British Medical Journal, which explored the relationship between exercise and cancer, exercise affects several biological functions that may directly influence your cancer risk. These effects include changes in:
Cardiovascular capacity Energy balance Pulmonary capacity Immune function Bowel motility Antioxidant defense Hormone levels DNA repair
If You Have Breast Cancer, Exercise is Also Beneficial
Many health care practitioners advise their patients to avoid exercise during and after cancer treatment. But increasing evidence is showing that this outdated advice is actually causing cancer patients harm, as regular exercise can lead to a number of health improvements for cancer patients, including:
- Better aerobic fitness
- Increased muscular strength
- Improved quality of life
- Less fatigue
Harvard Medical School researchers found patients who exercise moderately -- 3-5 hours a week -- reduce their odds of dying from breast cancer by about half as compared to sedentary women, so this is a very powerful strategy. In fact, any amount of weekly exercise increased a patient's odds of surviving breast cancer. This benefit also remained constant regardless of whether women were diagnosed early on or after their cancer had spread.
Patients receiving the biggest boost from exercise were those most sensitive to estrogen, the most commonly recognized hormone-sensitive form of breast cancer. (Previous research has shown exercise lowers estrogen levels, which can fuel the growth of breast cancer cells.) However, it's reasonable to assume that exercise would likely be beneficial for many types of cancer patients.
Often, you will be able to take part in a regular exercise program -- one that involves a variety of exercises like strength training, core-building, stretching, aerobic and anaerobic -- with very little changes necessary.
However, you may find that you need to exercise at a lower intensity or for shorter durations at times. Always listen to your body and if you feel you need a break, take time to rest. Even exercising for a few minutes a day is better than not exercising at all, and you'll likely find that your stamina increases and you're able to complete more challenging workouts with each passing day. In the event you are suffering from a very weakened immune system, you may want to exercise in your home instead of visiting a public gym.
How to Optimize Your Exercise Program to Achieve the Most Benefits
As mentioned, ideally your fitness program should be comprehensive, providing activities that will improve your strength, flexibility, cardiovascular fitness and fat-burning capabilities with high-intensity "Peak Fitness" exercises.
During 'peak fitness exercises,' you raise your heart rate up to your anaerobic threshold for 20 to 30 seconds, followed by a 90-second recovery period. You repeat this cycle for a total of eight repetitions. Peak exercises are particularly beneficial because this type of interval training triggers the natural production of human growth hormone (HGH), also known as "the fitness hormone." HGH plays an integral role in maintaining youthfulness and strength. (For an in-depth explanation of my Peak Fitness regimen, please review this past article.)
Another boon of Peak Fitness exercises is the amount of time you save. Including a three-minute warm up and two-minute cool down, your total time investment is a mere 20 minutes as opposed to your regular hour-long treadmill session, and you are really only exerting yourself for four minutes.
Generally, a 20-minute session about three times a week is all you need to stay fit, along with your strength-training, flexibility, stretching and so on, on alternate days.
Other Important Breast Cancer Prevention Strategies
I recently interviewed Dr. Christine Horner, a board certified general- and plastic surgeon, who shared her extensive knowledge about breast cancer—its causes and its cures, and the pro's and con's of various screening methods. I suggest you listen to that interview now, in addition to learning about the many all-natural cancer-prevention strategies below.
In the largest review of research into lifestyle and breast cancer, the American Institute of Cancer Research estimated that about 40 percent of U.S. breast cancer cases could be prevented if people made wiser lifestyle choices. I believe these estimates are far too low, and it is more likely that 75 percent to 90 percent of breast cancers could be avoided by strictly applying the following recommendations.
- Eat healthy. This means avoid sugar, especially fructose, as all forms of sugar are detrimental to health in general and promote cancer. Also, focus on eating whole foods and fresh vegetables while avoiding cancer-causing foods.
- Vitamin D. There's overwhelming evidence pointing to the fact that vitamin D deficiency plays a crucial role in cancer development. You can decrease your risk of cancer by MORE THAN HALF simply by optimizing your vitamin D levels with adequate sun exposure. And if you are being treated for cancer it is likely that higher blood levels—probably around 80-90 ng/ml—would be beneficial. The health benefits of optimizing your levels, either by safe sun exposure (ideally), a safe tanning bed, or oral supplementation as a last resort, simply cannot be overstated.
In terms of protecting against cancer, vitamin D has been found to offer protection in a number of ways, including:
- Regulating genetic expression
- Increasing the self-destruction of mutated cells (which, if allowed to replicate, could lead to cancer)
- Reducing the spread and reproduction of cancer cells
- Causing cells to become more highly differentiated (cancer cells often lack differentiation)
- Reducing the growth of new blood vessels from pre-existing ones, which is a step in the transition of dormant tumors turning cancerous
To learn the details on how to use vitamin D therapeutically, please review my previous article, Test Values and Treatment for Vitamin D Deficiency.
- Get proper sleep both in terms of getting enough sleep, and sleeping between certain hours. According to Ayurvedic medicine, the ideal hours for sleep are between 10 pm and 6 am. Modern research has confirmed the value of this recommendation as certain hormonal fluctuations occur throughout the day and night, and if you engage in the appropriate activities during those times, you're 'riding the wave' so to speak, and are able to get the optimal levels. Working against your biology by staying awake when you should ideally be sleeping or vice versa, interferes with these hormonal fluctuations.
According to Dr. Horner:
"If we, for instance, go to bed by 10, we have higher levels of our sleep hormone melatonin; there's a spike that occurs between midnight and 1am, which you don't want to miss because the consequences are absolutely spectacular.
Melatonin is not only our sleep hormone, but it also is a very powerful antioxidant. It decreases the amount of estrogen our body produces. It also boosts your immune system… And it interacts with the other hormones. So, if you go to bed after 10… it significantly increases your risk of breast cancer."
- Effectively address your stress. The research shows that if you experience a traumatic or highly stressful event, such as a death in the family, your risk of breast cancer is 12 times higher in the ensuing five years. So be sure you tend to your emotional health, not just your physical health.