MONDAY, July 12 (HealthDay News) -- There's no lack of scientific evidence proving that staying in shape and eating right are critical to a long and healthy life, but the fact that over 8 million Americans have histories of heart attack, stroke or heart failure suggests that too few are taking the message seriously.

That's the theme of a new scientific statement from the American Heart Association (AHA), which reviewed 74 previously published studies and developed specific behavioral-health strategies to help people stay heart-healthy.

The AHA finds that common-sense steps -- things as simple as writing down how much you exercise each day -- can keep people on track to stay heart-healthy.

"If the patient works with the doctors and writes it down, like keeping diaries of either food or activities, that that small bit of information can really help translate into the patient keeping motivated to follow the healthier lifestyle," noted Dr. Mary Ann McLaughlin, president of the AHA's New York City Board of Directors.

"This is a systematic review of multiple studies that have addressed lifestyle changes as they relate to physical activity and diet," added Dr. Ralph Sacco, AHA president and a professor of neurology, epidemiology and human genetics at the University of Miami Miller School of Medicine. "It's a very rigorous scientific process that grades and reviews all the existing literature that is out there on behavioral change. This paper actually talks about the scientific evidence supporting approaches of how to change."

The new statement was released online Monday and will appear in the July 27 issue of Circulation.

Heart disease remains the number one killer of both men and women in United States. Lifestyle factors, namely a poor diet and lack of physical activity, are major culprits in the twin epidemics of obesity and heart disease.

According to background information in the study, improving such lifestyle factors to eradicate major cardiovascular disease would boost Americans' average life expectancy by close to 7 years.

Having a good sense of your current cardiovascular condition is a good start, the experts said.

"'Life's Simple 7' is one way people can understand what the risks are and then begin to take control of their own health," Sacco said. The AHA program asks Americans to follow seven guidelines for a healthy life, including monitoring their blood pressure and staying active.

Other studies revealed that cognitive-behavioral strategies -- interventions that help a person change specific unhealthy behaviors -- are a cornerstone of efforts to making lasting lifestyle changes.

Setting concrete goals is also important, and goals that target a behavior (how much you eat, for example) rather than an outcome (blood pressure levels, for instance) are even better, several studies have found.

In conjunction with this, those who are successful at making lifestyle changes also tend to self-monitor, not only to understand what their foibles and stumbling blocks are, but also to monitor progress. Here it helps to actually track your program, writing down how far you're walking or how much you're eating and giving yourself credit for progress made.

"If you look at weight loss, plenty of studies show that those who are successful are the ones that write down honestly what they eat every day," said McLaughlin, who is also associate professor of medicine and cardiology at Mount Sinai Medical Center in New York City. "This particular guideline showed that if that same thing goes for physical activity, if the doctor says go out and exercise 30 minutes a day and write it down, that that interaction helps motivate the patient to put it down. Once they see it in print, they're more likely to keep up with it."

Follow-up is also important; the more you keep in touch with a healthcare provider or mentor, the more likely you are to get weight off, keep it off and minimize your future heart risks.

But it's going to take more than individual efforts to effect any kind of lasting change, the authors stated.

"AHA has an advocacy committee that has set some strategic goals that we want policy makers to consider," Sacco said.

These include more physical activity in the schools and programs specifically targeted to preventing childhood obesity (such as Michelle Obama's "Let's Move" initiative).

Changes in food labeling, such as those in place in New York City and other areas, help make consumers more aware of what they're putting in their bodies and therefore could also help, Sacco said.

Many cities are already mandating limits on trans-fats.

"Calorie labeling or quantity labeling is important for food items and menu labeling," Sacco said.

And more preventive services need to be covered under the Affordable Health Care Act, he added.

More information

Visit the American Heart Association for more on how to take care of your heart.