The association of heart rate variability examined in supine and standing position with ambulatory blood pressure monitoring in anorexia nervosa.

OBJECTIVE: To evaluate the association of heart rate variability (HRV) examined in supine and standing position with ambulatory blood pressure monitoring (ABPM) in patients with anorexia nervosa (AN).

METHODS: HRV in supine and standing position and ABPM were examined in 30 AN patients and 30 control subjects. The correlations between HRV and ABPM were evaluated.

RESULTS: The average age was 25±5 in AN patients and 25±4 years in controls (NS). LF (low frequency) power in AN patients and controls was comparable in supine position. LF power significantly increased during standing in controls, but no increment was detected in AN patients. The HF (high frequency) power was significantly increased in AN patients in supine position, but after standing was comparable with controls. The ratio LF/HF was lower both in supine and standing position in AN patients but the differences did not reach statistical significance. Blood pressure values in AN patients were comparable with controls in supine position but were significantly lower in standing position. Ambulatory blood pressure values were significantly lower in AN patients during active but not sleeping period. In standing position HF and LF powers positively and LF/HF negatively correlated with ABPM blood pressure values during active period in controls while in AN patients only LF power correlated with diastolic and mean blood pressures.

CONCLUSION: The lower ABPM values in AN patients during active period in comparison with control subjects may be explained by HRV changes, mainly by its impaired relations with blood pressure in standing position.