Cancer Loves a Sitting Duck

For decades, researchers have known there is a link between obesity and breast cancer — and exercise has been recommended strongly for both prevention and recovery. But new research highlights exactly how exercise helps combat the disease.

Previously, adipose tissue (or body fat) was thought of as a storage form of energy. Now, fat cells are understood to be active cells that produce more than 400 adipokines (hormones) — which eventually end up in the blood and make their way around the body.

“Voluntary and rigorous exercise can counteract, and even completely prevent, cancer growth that [is] caused by obesity,” said the lead researcher.

“Our research has found that the characteristics of hormones produced by fat cells in obese people can promote breast cancer growth, whereas in lean people it prevents growth,” said Michael Connor, a York University professor. “The characteristics of those hormones differ depending on whether the person is lean or obese, and that determines whether the cancer grows or not.”

Using a rodent model, Connor and his team looked at whether the fat cells play a role in the link between obesity and breast cancer, and whether interventions targeted at obesity counteract any life-threatening effects of breast cancer.

The research published in the Journal of Applied Physiology points to exercise — which has none of the harmful side effects of many cancer drugs. Exercise is a potentially beneficial therapy in some breast cancer patients.

The recent study has revealed specifically that adiponectin and leptin are possible reasons for poorer response to therapy and higher risk of death in obese individuals than in others.

“Our study shows that voluntary and rigorous exercise can counteract, and even completely prevent, the effects on cancer growth that are caused by obesity. We also show that even moderate exercise can lead to slowing of breast cancer growth and that the more exercise you do, the greater the benefit,” said Connor.

[lz_bulleted_list title=”Moderate Intensity Activities” source=”http://www.cancer.org”]Brisk walking|Dancing|Biking|Yoga|Golfing|Tennis|Yard work/gardening[/lz_bulleted_list]

Exercise is one of the most important things you can do to help guard against many types of cancer, according to the National Cancer Institute. Dozens of previous studies have shown that women who exercise have a 30 percent to 40 percent lower risk of breast cancer than their sedentary peers. The American Cancer Society recommends all adults get at least 2.5 hours of moderate intensity or 1.25 hours of vigorous intensity activity each week.

It’s not just breast cancer that exercise is said to fight, of course — up to one-third of all cancer-related deaths in the United States are said to be due to obesity and a sedentary lifestyle.

Moderate-to-vigorous physical activity was also recently shown to improve subjective memory among breast-cancer survivors, who often complain about memory problems. A recent study at Northwestern Medicine in Chicago, Illinois, suggests that physical activity alleviates stress and benefits women psychologically, which in turn aids their memory.

A surprising finding, according to researchers, is that memory problems appear to be related to the high stress load cancer survivors experience, and may not be specific to chemotherapy or radiation treatments.

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“Our research suggests these self-reported memory problems may be emotionally related,” said lead author Siobhan Phillips, assistant professor of preventive medicine at Northwestern University Feinberg School of Medicine. “These women are frightened, stressed, fatigued, tapped out emotionally, and have low self-confidence, which can be very mentally taxing and can lead to perceived memory problems.”

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Investigators looked at memory and exercise in breast cancer survivors in two study groups: one in self-reported data for 1,477 women across the country. the other in accelerometers worn by 362 women. The findings linking improved memory to higher levels of physical activity were consistent across both groups.

The study was supported by grants from the National Institute on Aging and the National Cancer Institute, and was published recently in the journal Psycho-Oncology.