Figure 1.
Correlation of low-frequency/high-frequency spectral power of heart rate variability with resting energy expenditure. Linear regression for low-frequency/high-frequency (LF/HF) heart rate variability spectral power computed from fast Fourier transform analysis of electrocardiogram RR intervals for ten healthy 18–20-year-old African American males during 20 min trials of uncontrolled breathing (a) and paced breathing at 0.2 Hz (b) after metabolic provocation with a 900 Cal test beverage. R 2 = .38; P < .05 and .68; P < .01, 8 df, respectively.