Exercise capacity decreases with age—this is something most fitness professionals already know. But until recently, scientists did not know how much exercise women should be able to do relative to their age. Researchers answered this question in the August 4 issue of The New England Journal of Medicine (2005; 353 , 468–75) by creating a nomogram, which is a graph or chart that represents numerical relationships.
“The current American College of Cardiology/American Heart Association exercise guidelines and standards are based on exclusively male data,” says Martha Gulati, MD, study author and cardiologist at Northwestern Memorial Hospital, Chicago, in an official university press release. “Women were being measured on the same scale as men. From the study, we see [that] a woman and man of the same age who exercise the same amount have a different age-predicted exercise capacity. This study provides women and clinicians a simple chart that is able to predict with adjusted levels factoring in age, lifestyle and exercise capacity.”
The study included 5,721 asymptomatic women from the Chicago metropolitan area. Participants were 35 years or older, had no active cardiovascular disease and were able to walk on a treadmill. Another cohort of 4,471 symptomatic women came from a different study group that had been referred for stress test evaluation. Researchers used this group to corroborate the model. All women underwent a treadmill exercise test, using the Bruce Protocol. Exercise capacity was measured in metabolic equivalents, or METs.
The researchers found that normal, healthy women who could not achieve 85% of their age-predicted exercise capacity were twice as likely to die within 8 years as those who could achieve greater than or equal to 85%. According to Gulati, this is especially important in younger women, because the further they deviate from their age-predicted fitness levels, the higher their risk of cardiac death.