LILLE, FRANCE. There is increasing evidence that an elevated heart rate is associated with an increased risk of sudden cardiac death. In the Paris Prospective Study, which included more than 7700 men followed up for 23 years, the mean difference between controls and patients who died suddenly from cardiac arrest was 4.1 beats per minute.
A group of European researchers now reports that regular fish consumption can lower heart rate by as much as 2 bpm. Their study included 9758 men aged 50 to 59 years from four European cities (Belfast, Lille, Strasbourg, and Toulouse). Twenty-seven per cent of the men consumed fish less than once per week, 47% consumed fish once a week, 20% twice a week, and the remaining 6% more than twice a week. The average heart rate (adjusted for age, physical activity, smoking, alcohol consumption, etc) was 67.5 bpm in men consuming fish less than once per week and 65.6 bpm in men consuming fish more than twice per week.
Fish consumers also had lower triglyceride levels, lower blood pressure (both systolic and diastolic), and higher levels of beneficial HDL cholesterol than did non-consumers. The erythrocyte content of DHA (docosahexaenoic acid) in the blood was found to be inversely correlated with heart rate.
The researchers point out that there is considerable evidence that omega-3 fatty acids such as those found in fish and fish oils stabilize the electrical activity of heart cells by elevating the action potential threshold and prolonging the relative refractory time. There is also evidence that a high omega-3 content of blood cells and serum cholesterol esters is associated with increased heart rate variability. A higher heart rate variability has been associated with a decreased risk of cardiac disease and a longer lifespan.
Dallongeville, Jean, et al. Fish consumption is associated with lower heart rates. Circulation, Vol. 108, August 19, 2003, pp. 820-25