n-3 fatty acids linked to improved cardiac fitness in CAD patients
MedWire News: Levels of n-3 fatty acids are associated with three key exercise parameters in patients with stable coronary artery disease (CAD), say researchers.
The team reports that levels of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were positively associated with treadmill exercise capacity, exercise time, and heart rate recovery time in 992 participants of the Heart and Soul Study.
"These findings support the hypothesis that n-3 fatty acids may increase vagal tone and physical conditioning," say Brian Moyers (University of California, San Francisco, USA) and team.
Study participants underwent an exercise treadmill test, which the researchers used to calculate exercise capacity (total metabolic equivalents [METs] achieved at peak exercise) and heart rate recovery time (difference between the maximum heart rate during exercise and heart rate 1 minute into recovery).
The team then used blood sample data collected between September 2000 and December 2002 to examine the relationship between levels of n-3 fatty acids and exercise parameters.
Patients with above average n-3 fatty acid levels had a significantly better heart rate recovery time, exercise capacity, and mean exercise time than those with below average levels, at 27.2 versus 23.8 beats/min, 8.0 versus 6.9 METs, and 7.0 versus 5.8 min, respectively.
Indeed, patients in the highest tertile of EPA and DHA achieved a 13% quicker recovery time, 14% higher exercise capacity, and 17% longer exercise time than those in the lowest.
Furthermore, each standard deviation increase in DHA and EPA decreased the age-adjusted odds for "poor" heart rate recovery (<16 beats/min), exercise capacity (<5 METs), and exercise time (<3 minutes) by 30%, 30%, and 40%, respectively.
n-3 fatty acids are found at high levels in marine fish oils and multiple studies have demonstrated the protective effects of fish oil supplementation on cardiac health.
Writing in The American Journal of Cardiology the researchers say: "A plausible explanation for these findings is that long-term fish oil consumption improves cardiac fitness in patients with CAD."
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By Nikki Withers