In humans, an increase in HRV following a myocardial infarction is associated with a decreased risk of fatal arrhythmias.24 Several studies suggest that omega-3 FA (especially DHA) may improve parameters of autonomic function, including HRV and baroreflex sensitivity. Hulguin et al, in this issue of CHEST (see page 1102), published a study addressing the effects of these FA on HRV. They administered fish oil (2 g/d providing 1.7 g of EPA plus DHA) or soy oil (2 g/d providing 0.13 g of the short-chain omega-3 FA, α-linolenic acid [ALA]) to 52 residents of a Mexican nursing home. HRV was assessed with 6-min readings obtained every other day for a 2-month run-in period and a 6-month supplementation period. They reported that both supplements improved HRV, with the fish oil supplement having a somewhat greater impact than the soy capsules. These findings should be considered preliminary, however, because there was no true placebo arm in the study (although most researchers in the field would consider the 2 g of soy oil a placebo, given the very small amount of ALA it provided). There was no analysis of the differences in response between the groups; thus, the fish oil supplement may not have been statistically different from the soy supplement. In addition, the generalizability of the findings to the US dietary setting remains to be determined. Nevertheless, this study lends support to the hypothesis that omega-3 FA can improve autonomic function, and thus potentially decrease the risk for life-threatening cardiac arrhythmias.