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Modulation of heart rate variability by dietary carbohydrate in healthy adolescent African‐Americans
Author(s) -
Austin Rachel E.,
Bond Ver,
Polk Octavius D.,
Millis Richard M.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1089.9
Subject(s) - postprandial , ingestion , heart rate variability , respiratory exchange ratio , medicine , endocrinology , carbohydrate , autonomic nervous system , heart rate , obesity , physiology , blood pressure , insulin
Low heart rate variability (HRV) after eating may be a risk factor for obesity among African‐Americans because of its association with a limitation of postprandial sympathetic regulation of adipokinesis and fat utilization. Purpose The present study was designed to test the hypothesis that a subpopulation of adolescents may be differentiated by changes in HRV after ingesting beverages of high carbohydrate or high fat content. Methods HRV was computed as the standard deviation of the normal‐normal (SDNN) and as the very low, low and high frequency spectral powers measured on electrocardiogram (ECG) RR intervals during paced breathing. Respiratory exchange ratio (RQ) and metabolic energy expenditure were measured. Results The results showed that RQ consistently increased after ingestion of the high carbohydrate and did not change consistently after ingestion of the high fat beverages. The peak increment in RQ was associated with an increase in the very low frequency and a decrement in the high frequency in the absence of consistent changes in the low frequency ECG spectral power. Conclusion These findings suggest that ingestion of high‐carbohydrate may produce sympathetic modulation of metabolism and thermogenesis in healthy adolescent African‐Americans. Furthermore, carbohydrate induced production of carbon dioxide may function as a metabolic signal for autonomic nervous system activity and HRV. The results of this study suggest that the increment in very low frequency ECG spectral power associated with ingestion of carbohydrate may be a physiological marker for postprandial sympathetic mediated adipokinesis, a limitation of which could be a marker of increased risk for obesity.