Moderate exercise protects elderly hearts

By Sarah Guy, medwireNews Reporter

The more exercise taken by individuals aged 65 years and older, the less likely biomarkers indicative of cardiac injury and new-onset heart failure are to increase, show US study findings.

Study participants who scored highest for physical activity were a respective 50% and 70% less likely to have significant increases in N-terminal pro-B-type natriuretic peptide (NT-proBNP) and cardiac troponin T (cTnT) levels compared with their peers with the lowest physical activity scores.

Furthermore, higher activity scores were associated with lower long-term heart failure incidence over the 2-3 year follow up, report the researchers in the Journal of the American College of Cardiology.

"Our findings raise the possibility that the trajectory of biomarker change and the subsequent [heart failure] risks associated with increasing levels may be modifiable by changes in life-style even at an advanced age," write Christopher deFilippi (University of Maryland School of Medicine, Baltimore) and colleagues.

The study cohort included 2933 individuals with samples of NT-proBNP and cTnT taken at baseline and 2-3 years later. Significant increases of these biomarkers were respectively defined as a greater than 25% increase between measurements to a level of at least 190 pg/mL, and an increase of more than 50% among those who had detectable (=3 pg/mL) levels.

Participants self-reported a median weekly energy expenditure of 735 kcal, with 26.2% reporting a walking pace of less than 2 mph, 42.7% reporting a pace of between 2 and 3 mph, and 31.2% reporting a walking pace of more than 3 mph.

The probability that an individual would have significant increases in biomarkers at the 2-3 year follow up fell from 37.4% and 30.2% for those reporting the least activity per week to 19.5% and 11.4% for those who reported the most, for NT-proBNP and cTnT, respectively, report the researchers.

Odds ratios for significant increases in biomarkers between examinations confirmed this trend, at 0.50 for NT-proBNP and 0.30 for cTnT when comparing the highest with the lowest activity scores, and this association remained when kilocalories per week and walking pace were analyzed separately.

A total of 822 cases of incident heart failure occurred after a median 10.8-year follow up from the second biomarker measurement. However, the incidence diminished with progressively higher levels of activity in individuals both with and without significant increases in either biomarker, report the authors.

Remarking on the results, editorialists Christopher O'Connor and Tariq Ahmad (Duke University Medical Center, Durham, North Carolina) say that the possibility of a biomarker measurement providing an objective assessment of exercise efficiency in this population is an "exciting proposition" worthy of further evaluation.

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