Is heart rate variability a physiological marker of short-term mood changes? A meta-analysis

Heart rate variability (HRV) is widely studied as a physiological marker of autonomic and emotional regulatory processes and is increasingly explored as a physiological signal for inferring affective states in digital health applications. However, it remains unclear whether HRV reliably tracks short-term mood changes and, more broadly, whether physiological signals capture moment-to-moment emotional dynamics. To address this question, we conducted a preregistered systematic review and multilevel meta-analysis of experimental studies examining HRV responses to induced positive and negative mood changes (85 studies, 165 effect sizes, n = 4,341 participants). Across studies, HRV overall decreased following negative mood induction (d = -0.179, p = 0.002), and increased following positive mood induction (d = 0.228, p = 0.009); however, substantial heterogeneity was observed across studies. Subgroup analyses indicated that the association of HRV-mood coupling depended on both physiological and experimental factors, with significant effects observed when the root mean square of successive differences (RMSSD) was used as the HRV metric, while other commonly used HRV metrics did not show HRV-mood change associations. Age and gender composition of the samples did not moderate these associations. By identifying the conditions under which HRV tracks positive and negative mood changes, this meta-analysis clarifies when HRV may reflect short-term affective dynamics and establishes its potential as a physiological correlate of mood.