OBJECTIVE: Anorexia nervosa (AN) typically begins in early adolescence and other than weight status has few reliable biomarkers. Early diagnosis is a critical prognostic factor, but this can be clinically challenging. Heart rate variability (HRV), the beat-by-beat variance in heart rate (HR), may provide a unique assessment for the presence of AN because it has clinical utility as a biomarker of cardiac autonomic control in various populations (e.g., athletes, the aged, those with cardiovascular diseases, etc.). We present a review of the literature examining HRV in those with AN. METHOD: Relevant publications were selected from PubMed using the search terms \'anorexia nervosa AND (HR OR HRV)\'. Twenty papers were selected and reviewed. RESULTS: The majority of studies suggest that those with AN have markedly and consistently elevated HRV compared to controls, even greater than among young athletes. However, no studies have explored HRV as a biomarker for AN. DISCUSSION: Future studies on HRV should elucidate its role as a diagnostic biomarker for AN as well as its responsiveness with serial measurement to track response rates and predict relapse.