by University of St Andrews

Illustration of the hypothesized and examined links between vagal tone, HRV, and reactive aggression in aggression research. Credit: Aggressive Behavior (2024). DOI: 10.1002/ab.70004

New research from the University of St Andrews debunks the theory that Heart Rate Variability (HRV) is linked to aggressive behavior.

Led by Ph.D. candidate Annah McCurry from the School of Psychology and Neuroscience, the study, published in Aggressive Behavior, screened 705 previous studies and found no evidence that HRV correlates with reactive aggression.

HRV, or heart rate variability, measures the variation in time between heartbeats, which is controlled by the body's autonomic nervous system. Wearable devices like smartwatches often track HRV, with past research suggesting it could help gauge a person's stress resilience. However, McCurry's findings indicate that HRV may not be useful as an indicator of aggression.

McCurry said, "Aggression researchers want to predict aggression so we can prevent it before it occurs. Since poor emotion regulation has been linked with aggression, we want to find an objective biological indicator of emotion regulation, and some have tried to use HRV as this marker."

"Our findings are definitive: researchers should stop using low HRV as a biomarker of aggression."

For the general public, this means relying on wearable tech to manage or predict emotional upset or aggression might be misleading.

McCurry said, "Wearable physiology trackers like sports watches are fun, but they are not magic crystal balls.

"We remain convinced that the development of an effective biomarker could transform the way we as a society predict, monitor, and prevent reactive aggression in our population.

"Unfortunately, empirical data clearly indicates that HRV is not an effective biomarker for aggression and the search for a solution must continue."

More information: Annah G. McCurry et al, Theories of Arousal Predict a Link Between Heart Rate Variability and Reactive Aggression: Meta‐Analytic Results Disagree, Aggressive Behavior (2024). DOI: 10.1002/ab.70004

Provided by University of St Andrews