Heart Rate Variability in Anorexia Nervosa: A Systematic Review and Meta-Analysis on the Moderating Role of Measurement Duration and Clinical Stage.
Marta Victoria Santiago, Miguel Heres, Cristina Mazas et al.
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In 30 seconds
This systematic review and meta-analysis assessed heart rate variability (HRV) in people with anorexia nervosa (AN) compared with healthy controls, including differences by clinical stage and recording duration. Nineteen studies were included, 16 of which contributed data from 805 participants. In acute AN, heart rate was lower (SMD = -1.807; 95% CI: [-3.36, -0.26]; p = 0.022) and the LF/HF ratio was reduced (SMD = -0.74; 95% CI: [-1.179, -0.301]; p < 0.001), consistent with parasympathetic predominance. Short-term recordings showed more consistent differences than 24-h recordings.
Key findings
- Acute AN was associated with lower heart rate than healthy controls (SMD = -1.807; 95% CI: [-3.36, -0.26]; p = 0.022).
- The LF/HF ratio was reduced in acute AN (SMD = -0.74; 95% CI: [-1.179, -0.301]; p < 0.001), indicating parasympathetic predominance.
- With 5-min recordings, SDNN (SMD = 0.539; p = 0.008) and HF (SMD = 0.679; p = 0.037) showed significant differences.
- SDNN and RMSSD tended to be higher in AN, but these differences were not statistically significant and had low-certainty evidence.
Why it matters
The findings suggest that HRV can reflect autonomic alterations in AN, particularly during the acute phase, but interpretation depends on recording duration. This matters when comparing HRV results across studies or considering the measure as a biomarker: short-term and 24-h recordings may not yield equivalent findings, and HRV may not consistently normalise during recovery.
What to keep in mind
Meta-regression by clinical stage was not feasible because too few studies were available. Evidence for higher SDNN and RMSSD was low certainty.