Fitness may actually be a more important factor than your weight when it comes to living a long, healthy life, a new study suggests.
Researchers report that older people who are fit -- even if they are also fat -- are likely to live longer compared with those who are out of shape. The study is the latest research to suggest that being a bit overweight may not be as dangerous to your health as other factors.
A November Centers for Disease Control and Prevention study suggested that being up to 25 pounds overweight doesn't appear to raise the risk of dying from cancer or heart disease. And a Duke University study in July posed a puzzling -- and controversial -- paradox in which obese people who'd endured a heart attack appeared to have a better chance of surviving it than their skinnier counterparts.
However, medical experts warn that you shouldn't ignore your body mass index completely; instead, they recommend using fitness as a means for maintaining a healthy body weight.
"Our results showed pretty clearly that fitness provides substantial protection against dying," says study author Steven Blair of the University of South Carolina at Columbia, who is also the director of research at the Cooper Institute for Aerobics Research in Dallas. "Even people who are obese, with a body mass index of 35 or higher, if they are fit, they have a much lower chance of dying than those who are unfit."
Blair and colleagues looked at 2,603 adults over age 60 and evaluated their fitness levels using treadmill tests. Their findings, to be published in the Journal of the American Medical Association, suggest that weight isn't everything.
Other medical experts not affiliated with the research agree with this conclusion.
"Performance measures are always better than appearance measures in anything," says Dr. Paul Thompson, director of cardiology at the Hartford Hospital and a professor of medicine at the University of Connecticut. "What something looks like does not tell you how it runs."
Blair concurs. "There is a great benefit to being fit," he says, "even if you are in fact obese."
Obesity Still a Big, Fat Problem
However, doctors warn that body fat cannot be ignored completely in the quest to get in shape.
"This study is one of several that weigh in on the relative importance of obesity and fitness," says Dr. Robert Vogel, a professor of medicine at the University of Maryland. "Some studies have found weight to be more important; others, such as this one, have found fitness to be more important. The true answer is that both are important."
Dr. Salim Yusuf, a professor of medicine at McMaster University in Ontario, Canada, agrees.
"People should do both -- keep a healthy body weight and enhance fitness," he says. "The most important message is that individuals should maintain a healthy weight and also exercise regularly to enhance fitness."
Being in shape not only makes you feel good but also provides substantial health benefits that can protect you from a number of chronic diseases, such as heart disease, diabetes and some types of cancer.
In addition, exercise prevents high blood pressure and boosts levels of high-density lipoprotein, or "good," cholesterol, which prevents plaques from building up in your arteries.
Exercise can even help reduce risk factors associated with obesity. Nathan Wong, director of the Heart Disease Prevention Program at the University of California at Irvine, says exercise can improve your health even if you carry a few extra pounds.
"We know abdominal obesity is associated with many other risk factors, such as insulin resistance, low HDL-cholesterol and elevated blood pressure," says Wong. "Increased fitness levels tend to reverse several of these effects."
Most important, exercise makes your heart stronger, so that if something does go wrong, you will be more likely to live through it.
"Exercise performance, or fitness, has long been known to be the best predictor of survival," Hartford Hospital's Thompson says.
"Exercise performance largely reflects heart performance and primarily stroke volume. If you have a good heart, and good stroke volume, you can put up with all sorts of bodily insults, including heart attacks, and keep on ticking, because you have good reserve."
Dr. C. Noel Bairey Merz, a professor of medicine at the UCLA David Geffen School of Medicine, explains that reserve is a measure of your heart's health. The healthier your heart or the more reserve you have, she says, the more likely you are to survive heart attacks and other diseases.
And it's exercise that can help you build up that reserve.
"Fitness is a measure of cardiovascular system reserve, and therefore a measure of that system's health," Merz explains. "Reserve is important to counteract stress such as illness … and being unfit is a marker for inadequate system reserve, a precursor for disease."
Simple Steps to a Healthier Heart
Improving your heart's health does not take a lot of time or effort, doctors say. Even just a small increase in fitness can improve your health and lower your chances of dying prematurely.
Blair says that becoming even moderately fit decreases the risk of early death by 50 percent. Highly fit individuals lower their risk by another 10 to 15 percent.
However, he adds, people must keep in mind that losing weight is also important for a heart-healthy lifestyle. Experts say that for the most part, it's uncommon to be fit and fat, which means staying trim is just as important as exercising.
"In real life, few abdominally obese patients have a high level of fitness, so practically from a public health point of view, getting across any message implying we place less importance on obesity is ill-advised," says Wong.
Blair agrees. "I would recommend people focus on healthful behavior," he says. "This includes exercising regularly, eating fruits and vegetables, eating whole grains, managing stress and not smoking."
And while trying to break unhealthy habits can be challenging, improving your health by exercising does not have to be as difficult or time-consuming.
"Most fitness can be developed and maintained by just 30 minutes of walking, five days a week," says Blair. "You don't even have to do it all at once. Taking three 10-minute walks a day is all it takes."