Science in the Spotlight:
Cancer Risk: Beyond the Scale
Compared to people at a healthy weight, those who are overweight or obese have an increased risk for cancer. Studies clearly show that regular physical activity can reduce these risks, but now cancer researchers are exploring whether it can provide protection from cancer independent of weight. Can physical activity reduce cancer risk regardless of the number on the scale?
“I believe it can,” said Stephen Farrell, PhD, Division of Education Service Officer at the Cooper Institute in Dallas, Texas. “Many research studies make the assumption that a person who is overweight is unfit.” Measuring physical activity in a study can be time-consuming and expensive, and so many researchers opt to use weight as a proxy measure for fitness and/or health.
“But there are fit and unfit people in all categories of weight. Think about smokers, many of whom are lean. We don’t make the assumption that they are healthy.”
Fit and Healthy
An important aspect of physical activity, he said, is its ability to lessen visceral fat, the fat deep within the abdomen that is often associated with overall health. In a recent study published in the journal Obesity, Farrell and colleagues examined the relationship of BMI and cardiorespiratory fitness to cancer mortality in more than 38,000 men. The men completed a comprehensive baseline exam between 1970 and 2001 that included a standard treadmill stress test to assess cardiorespiratory fitness. Results showed that higher levels of cardiorespiratory fitness were associated with lower cancer mortality – independent of obesity.
“We don’t want to ignore the health effects of obesity, but the good news is that people who are overweight or obese may be able to lower their risk of cancer by achieving a moderate level of fitness,” said Farrell, who is currently conducting a similar study in women.
Farrell suggests people strive to become more fit by developing realistic goals.
“Unfortunately, many people drop out of exercise programs because they don’t get the weight loss results they want right away,” said Farrell. People should focus on goals that are modest, achievable and realistic. “The key is to start slowly and build up, but take your time getting there.”
Mechanisms of Physical Activity
Henry Thompson, PhD, Director of the Cancer Prevention Laboratory at Colorado State University, agrees that physical activity irrespective of BMI can have benefits overall related to chronic disease prevention.
“Physical activity can help our bodies manage the use of glucose properly, which in turn, can protect us from disease and illness,” said Thompson, who has conducted several studies with AICR support. “Reasonable levels of physical activity also help tune up our bodies to deal with oxidative challenges and regulate our metabolic processes.”
“People need to integrate work and play for a better balance and try not compartmentalize their lives,” said Dr. Thompson. “Try to include work in your play and play in your work. There are countless benefits to maintaining a healthy lifestyle and a cafeteria of ways to increase physical activity that will help reduce your risk for obesity, diabetes, cancer and heart disease.”
This article is excerpted from ScienceNow.
Published on 05/05/2010