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Chronotropic incompetence to exercise separates low body weight from established anorexia nervosa
Author(s) -
Roche Frédéric,
Barthélémy JeanClaude,
Garet Martin,
Costes Frédéric,
Pichot Vincent,
Duverney David,
Kadem Myriam,
Millot Luc,
Estour Bruno
Publication year - 2004
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/j.1475-097x.2004.00561.x
Subject(s) - medicine , chronotropic , cardiology , heart rate , heart rate variability , body mass index , ambulatory , heart failure , anorexia nervosa , endocrinology , blood pressure , eating disorders , psychiatry
Summary Chronotropic incompetence (CI), characterized by an attenuated heart rate (HR) response to exercise could participate to the limitation of exercise capacity in anorexia nervosa (AN). Therefore, we evaluated the role of cardiac sympathetic responsiveness in AN patients. In addition, the ambulatory value of autonomic control using spectral analysis of heart rate variability (HRV) was determined and correlated to maximal exercise performance. Twenty‐two patients hospitalized for weight loss and suspicion of AN were included in the study. All performed a symptom‐limited exercise test with measurement of gas exchange for chronotropic response to exercise evaluation. Holter ECG recordings allowed daytime and night‐time spectral domain HRV analysis in order to evaluate the alteration of sympathetic control of HR in free‐living conditions. CI defined as a failure to achieve 80% of heart rate reserve (%HRR) was observed in 13 (59%) patients (CI+). This group presented a higher body mass deficit than the group without CI (CI−; −35·1 ± 8·7% versus −26·1 ± 10·7%; P <0·05). Obviously, patients with a lower body mass index (BMI < 16 kg m −2 , n = 14) revealed a more severe limitation to maximal exercise with a lower peak HR, a lower peak V o 2 , and a lower maximal O 2 pulse ( P <0·05). BMI was significantly correlated to peak V o 2 , maximal HR, and %HRR achieved at peak exercise. Daytime HRV parameters reflecting the sympathetic autonomic equilibrium (LF nu, LF/HF ratio) were significantly lower in CI+ patients. Blunted sympathetic response to maximal exercise is frequent and correlated to weight deficit. The present data suggest a major autonomic derangement in AN characterized by a cardiac sympathetic withdrawal.