Studies: Low fitness deadlier than excess weight

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Between 1986 and 2010, more than 20,000 Veterans underwent cardiac stress tests—walking on a treadmill, with electrodes taped to their chest—at the VA medical centers in Washington, DC, and Palo Alto, Calif. Some were undergoing routine physicals. Others were being checked for exercise-induced ischemia—blockages in blood flow to the heart, made worse by physical exertion.

The results of the stress tests, along with other data in the Veterans' electronic health records, have been a gold mine for Peter Kokkinos, PhD, and other VA researchers interested in learning about the link between exercise capacity and longevity. They have authored a string of publications, dating back to the late 1980s, that have helped answer numerous questions. Among them: Does being fit extend life even for those with diabetes, hypertension, or obesity? Is low fitness truly a more critical risk factor than any other?

The answer to both questions is "yes," according to many studies, such as these two from Kokkinos and colleagues:

• In a May 2012 article in Diabetes Care, the group described what they call the "BMI [body mass index]-mortality paradox." Looking at more than 4,000 white and African American men with diabetes, the team found that the greater the exercise capacity, the lower the mortality risk. There was also a twist: Among all the Veterans in general and African Americans in particular, mortality risk dropped as the Veterans got heavier. Compared against leaner Veterans with equal exercise capacity, fatter Veterans lived longer, on average. Similar patterns have been seen past studies. Researchers have yet to understand this puzzling paradox. (See sidebar on the "obesity paradox.")

Another lesson from the study: When Veterans with diabetes were fit, they outlived others who were less fit, even when the fitter Veterans carried the burden of additional risk factors, such as hypertension, high cholesterol, and obesity.

Kokkinos' conclusion: "In diabetes, it doesn't matter what your BMI is. You must be fit. Fitness trumps the deleterious effects of any additional risk factors, including excess body weight."

He and his coauthors wrote that the public health message of the findings is that "low fitness should be considered by health professionals to be as important a risk factor as other traditional risk factors."

• A study published in the April 2012 American Journal of Hypertension by Kokkinos and colleagues included a sample of more than 4,100 Veterans with high blood pressure who underwent stress tests at the Washington, DC, VA Medical Center. Once again, fitness overpowered other risk factors. According to the authors, the findings suggest that "in older hypertensive men, it may be healthier to be fit regardless of standard BMI category than unfit and normal weight."