Sodium lactate increases sympathovagal ratios in normal control subjects: spectral analysis of heart rate, blood pressure, and respiration.

We used spectral analysis of heart rate (HR), blood pressure (BP), and respiration to examine the effects of lactate on cholinergic and adrenergic influences on HR and BP variability, a technique found to be very useful in cardiovascular research. We specifically used high frequency (0.2-0.5 Hz) and midfrequency (0.07-0.15 Hz) powers to study cholinergic and adrenergic activity in nine normal control subjects before and after lactate and placebo infusions. Our results demonstrate a marked decrease in cholinergic activity and a significant increase in sympathovagal ratios of HR modulation after lactate infusions. This altered sympathovagal balance may contribute to the panicogenic effects of lactate in panic disorder patients.