Patients who started with low fitness levels but were able to improve to intermediate or high fitness levels reduced their risk of death during the study by roughly 40%, say the authors.
Exercise capacity is measured during an exercise stress test, which is typically performed on a treadmill or stationary bike. Someone with a higher maximal exercise capacity is able to achieve a faster walking pace or climb more stairs before getting tired, lead author Clinton Brawner told Reuters Health in an email interview.
“Maximal exercise capacity is our ability to do work. It is dependent on the health of the heart, lungs, blood, and muscles,” said Brawner, who is a researcher at the Edith and Benson Ford Heart and Vascular Institute at the Henry Ford Hospital in Detroit.
“More importantly, higher exercise capacity means an individual is able to complete activities of daily living, like working around the house, more easily and with less fatigue than someone with a lower exercise capacity,” Brawner said.
While there is a wealth of data to support the relationship between fitness and outcomes, like premature death, there are only a few studies that have evaluated whether changes in fitness are related to outcomes and none included women, said Brawner.
To address that knowledge gap, Brawner and colleagues analyzed data from the Henry Ford Exercise Testing (FIT) project, which involved adults from Detroit, Michigan who underwent physician-ordered exercise stress tests on treadmills between 1991 and 2009.
As reported in the Mayo Clinic Proceedings, the study team looked at more than 10,000 patients who performed two exercise stress tests at least one year apart.
After an average follow-up of 8.6 years, 9.5% of the men and 7.4% of the women had died.
