The very good news in a massive study recently completed by the Cooper Institute in Dallas is that middle-aged men and women who do cardiovascular exercise regularly can reduce substantially their risk of dying from heart disease.
"This is a landmark study," said Venkatramin Srinivasan, a cardiologist in the West Penn Allegheny Health System. "The important thing is the correlation of a person with high fitness and high risk factors [for heart disease, such as high blood pressure, diabetes and smoking]. If you have these risk factors, but you are fit, your risk becomes that of a person without risk factors. That's a very important point. Nobody has shown that before."
The Cooper Institute was founded in 1970 by Kenneth Cooper -- who coined the term "aerobics" -- to study the effects of exercise and diet on health.
Researchers headed by Jarett D. Berry, a cardiologist at the University of Texas Southwestern Medical Center in Dallas, tracked 11,049 men who were examined at the Cooper Institute before 1990 until they died, or attained the age of 90.
According to this longitudinal study, there is only a 4.9 percent chance that a 55-year-old man who is very fit will die of heart disease before age 80. That compares to a 9.8 percent risk for a moderately fit middle-aged man, a 19.6 percent risk for a low-fit man, and a 28.7 percent risk for a sedentary man.
The bad news is that you have to be really, really fit to be in the top category. Cooper Institute researchers measured fitness by how long it took a test subject to run a mile on a treadmill. To be in the "very fit" category, a man has to run that mile in 8 minutes, a woman in 9 minutes.
To be judged "moderately fit" by the Cooper Institute's standards, a man has to run that mile in 9 minutes, a woman in 10 1/2 minutes.
Dr. Srinivasan is 59. To get exercise, he walks on a treadmill for 30 minutes most days.
The Cooper study will change his exercise pattern, Dr. Srinivasan said.
"I don't think I can run an 8-minute mile," he said. "This is a motivating tool."
Daniel Edmundowicz, director of preventive cardiology at the UPMC Cardiovascular Institute, said he wasn't surprised by the study because earlier studies by the Cooper Institute had shown linkages between physical fitness and heart health.
"An important distinction to make is that this is an observational trial, not an intervention trial," he said. "This wasn't taking someone who was really unfit and making a program to change that."
"You need prospective studies," Dr. Srinivasan agreed. "[The Cooper Institute study] can tell you how the whole population behaves. It does not necessarily translate to a single individual. I don't want people to read this article and then go running on a treadmill."
Especially if you are middle-aged, you should check with your physician before beginning an exercise program, the doctors said.
Running on a treadmill is great for people who like running on a treadmill, but, said Dr. Edmundowicz, "it's less the type of activity [you do] than getting out and doing something you like to do."
The study should encourage people to exercise more, he said.
"Human beings were designed to move," Dr. Edmundowicz said. "Any way we can get folks to do that is beneficial."
Jack Kelly: email@example.com or 412-263-1476.