Fish Helps Heart Rate

In the study, published in the Journal of the American College of Cardiology, researchers analyzed dietary information on 5,096 men and women age 65 and over who participated in a large heart-health study from 1989-1990.
Researchers then compared the participants' fish-eating habits to their electrocardiogram (ECG or EKG) test results. They divided the participants into five groups depending on the amount of tuna or other baked/broiled fish intake they reported over the previous year.
The results showed eating tuna or other baked or broiled fish in the group of participants who reported eating the most, compared to the group who ate the least, appeared to improve the electrical function of the heart in at least three ways, including:
Lowering the resting heart rate.
Slowing the time between when the heart is signaled to pump blood and when the pumping occurs.
Reducing the risk of the heart's electrical system not resetting properly after each heartbeat.
"In contrast to intake of tuna or other broiled or baked fish, intake of fried fish had no association with the heart's electrical parameters," says Mozaffarian. "Previously, we have seen that intake of fried fish -- which in the U.S. are most often commercially sold fish burgers or fish sticks -- is not associated with blood levels of omega-3 fatty acids. This suggests that it may be the omega-3 fatty acids in tuna and other broiled or baked fish that are having a positive impact on the heart's electrical parameters."
Fish rich in omega-3 fatty acids include tuna, salmon, lake trout, mackerel, and herring.

SOURCES: Mozaffarian, D. Journal of the American College of Cardiology, Aug. 1, 2006; vol 48: pp 478-484. News release, American College of Cardiology.

P.S. You do not have to eat a huge amount of fish, just 1 or 2 servings a week.