Association of body fat percentage and heart rate variability measures of sympathovagal balance.
OBJECTIVE
We tested the hypothesis that body fat percentage determines cardiac sympathovagal balance in healthy subjects.


METHODS
Heart rate variability (HRV) measurements were made of the standard deviation of the normal-normal RR intervals (SDNN) and the low frequency/high frequency (LF/HF) ratio, from time domain and fast Fourier transform spectral analysis of electrocardiogram RR intervals during trials of uncontrolled and controlled (paced) breathing at 0.2Hz. Body fat percentage was measured by dual energy x-ray absorptiometric (DEXA) scanning. Significance of differences between uncontrolled and controlled (paced) breathing was determined by analysis of variance and correlations between body fat percentage and HRV measurements by Pearson's coefficient at P<0.05.


RESULTS
Percent body fat was negatively correlated with LF/HF during the uncontrolled breathing (r=-0.56, two-tailed P<0.05, one-tailed P<0.01) but not during the paced breathing trial (r=-0.34, (P>0.1).


CONCLUSIONS
We conclude that sympathetic activity produced by paced breathing at 0.2Hz can obscure the relationship between body fat percentage and sympathovagal balance and that high body fat percentage may be associated with low sympathetic modulation of the heart rate in healthy adolescent/young adult males.
Millis
Richard M
RM
Department of Physiology & Biophysics, Howard University College of Medicine, Washington, DC 20059, USA. rmillis@howard.edu
Austin
Rachel E
RE
Hatcher
Mark D
MD
Bond
Vernon
V
Faruque
Mezbah U
MU
Goring
Kim L
KL
Hickey
Brian M
BM
DeMeersman
Ronald E
RE
D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000378:metabolism; D050154:Adiposity / Q000502:physiology*; D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D004562:Electrocardiography; D004734:Energy Metabolism / Q000502:physiology; D005215:Fasting / Q000378:metabolism / Q000502:physiology; D005583:Fourier Analysis; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D056152:Respiratory Rate / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology*; D055815:Young Adult