Five Hundred Years of Mercury Exposure and Adaptation

Figure 6

Comparison of power spectra derived from hydrogen isotope ratios along the length of the hairs and power spectra derived from heart rate intervals (RR) in the same subjects. Note that the low- and high-frequency power bands are of comparable lengths but the spectral power appears different (NS) (“stacked” averaged spectra from all subjects). Red line hydrogen isotope ratios; green line heart rate variability (RR intervals). Spectral power, on the 𝑦-axis, is hydrogen isotope ratios (right) and RR intervals (left).