Fig. 5.

Effect of n-3 PUFAs on the change in heart rate and heart rate variability in response to the onset of submaximal exercise. As there were no significant differences noted between the various n-3 PUFA doses, these data have been combined. As indicated in Fig. 4, dietary n-3 PUFA, but not the placebo, produced a significant downward shift of the heart rate response that was accompanied by an upward shift in the high frequency component of the R-R interval variability (vagal tone index: 0.24–1.04 Hz; i.e., significant pre-post treatment effect). Despite the shifts in the curves, the absolute change in these variables induced by the exercise was not altered before or after the treatment (i.e., there was no significant pre-post treatment × exercise onset interaction). Placebo (n = 16) and n-3 PUFA (1–4 g/day, n = 35) are shown. Pre, before treatment began; post, after 3 mo of treatment.