Adults who increased their fitness level during an eight year period and those who sustained high fitness levels had lower HF hospitalizations later, compared with those who had persistently low fitness levels (0.64% vs. 0.88% per year), according to Ambarish Pandey, MD, of the University of Texas Southwestern Medical Center in Dallas and colleagues.
“These findings suggest that the [HF] risk related to low fitness may be modifiable with exercise training,” Pandey reported at the American Heart Association’s Quality of Care and Outcomes Research 2013 Scientific Sessions in Baltimore.
He and colleagues estimated fitness in metabolic equivalents (METs) among 9,050 adults (mean age, 48 years; 15% women) in two exercise tests conducted approximately eight years apart. Participants’ fitness levels were ranked in quintiles with Q1 representing low fitness and Q2 through Q5 representing high fitness levels.
The primary endpoints were change in METS and a change in fitness category between the first and second cardiorespiratory tests. The researchers observed 242 hospitalizations for HF after 60,635 person-years of Medicare follow-up.
Each MET increase in middle-age fitness correlated with a significant, 5% decrease in the risk of HF hospitalization in later life, after adjustment for baseline fitness level and other risk factors, Pandey and colleagues found.
From baseline to follow-up, HF hospitalization rates according to quintile were as follows:
- Sustained high level fitness — HF hospitalization rate of about 0.30%
- Low to high — about 0.65%
- High to low — about 0.75%
- Low to low — about 0.83%
For every MET improvement in fitness, middle-age study participants were 17% less likely to be hospitalized for HF as they aged (adjusted HR=0.83; 95% CI: 0.71-0.92 per MET), data indicated.
“People who weren’t fit at the start of the study were at higher risk for [HF] after age 65,” Pandey said in a statement. “However, those who improved their fitness reduced their [HF] risk, compared to those who continued to have a low fitness level eight years later.”
Study limitations included reliance on Medicare claims data to determine HF hospitalization rates and the results of two fitness tests, which may not account for other lifestyle changes over time.