A study published back in 2015 revealed a curious link between crime and unintentional injury rates in men and a low resting heart rate.
Now a similar study on women has uncovered much the same association, reminding us that risk-taking isn’t confined to any one gender.
Researchers from the US, Sweden, and Finland followed the criminal records of 12,499 women for up to 40 years and found those with a low resting heart rate were slightly more likely to be convicted of a non-violent crime.
It’s important to note that this doesn’t mean that women with low heart rates will likely become criminals.
The researchers also noticed that these women tended to experience more unintentional injuries. It’s suggested that lower activity in the autonomic nervous system, which regulates automatic bodily functions like heart rate, might make people more likely to seek out excitement and take risks.
“Lower autonomic arousal is a well-known correlate of criminal offending and other risk-taking behaviors in men, but few studies have investigated this association in women,” criminologist Sofi Oskarsson from Orebro University in Sweden and colleagues write in their published paper.
“The reported findings have potential implications for the prediction of future female crime.”
Crime prevention often involves looking at social factors along with people’s personalities, and rarely considering biological factors, such as the functioning of our nervous system. But Oskarsson and team wanted to see if there’s a link between women’s heart rates and their behavior.
The researchers followed 12,499 Swedish women who joined the military when they were around 18 years old, where physical exams recorded their heart rates and blood pressure. Then they kept track of any criminal convictions or unintentional injuries these women had for up to 40 years.
They found that women with the lowest resting heart rates – under 69 beats per minute (BPM) – were 35 percent more likely to be convicted of a crime compared to those with heart rates above 83 BPM.
There was also a significant association between having a heart rate below 69 BPM and higher conviction of non-violent crimes, when compared to those with a heart rate above 83 BPM. This link didn’t apply when only violent crimes were considered.
An analysis of systolic blood pressure (SBP) and criminal convictions found those with the lowest SBP (113 mmHg or lower) had a 26 percent increased risk of any crime compared to those with the highest SBP (134 mmHg or higher). Across other ranges between these two extremes, there were few significant associations between higher or lower SBP and crime.
Having a lower heart rate was also linked to a higher risk of treatment or death as a result of ‘unintentional injuries’, which excluded things like self-harm or vehicle crashes.
“Our finding that lower resting heart rate was associated with an elevated risk of unintentional injuries among female conscripts is notable,” the team writes, “in light of prior evidence that lower resting heart rate is also associated with a tendency to engage in extreme sports, such as skydiving, and with risky jobs such as bomb disposal work.
According to the researchers, we should exercise caution when interpreting these findings, as female military volunteers may not accurately represent the general population.
In a separate analysis, Oskarsson and colleagues compared the rates of crime and unintentional injuries in the sample of conscripts to a sample of 1,714,152 non-conscript women (those who did not volunteer for military service). Female military service members were more prone to accidents, while in contrast, they had lower crime rates overall than the non-conscript group.
If further and broader studies confirm these findings, it could help us understand the biological factors influencing the people who commit crimes so that we can develop better tactics to meet their needs and perhaps discourage them from resorting to antisocial behaviors.
“While these results warrant replication, findings indicate that reduced autonomic arousal, as indexed by lower resting heart rate in particular, may have the potential to serve as a predictor of criminal offending,” the authors write, “not only in men as suggested by previous studies, but also in women.”
The research has been published in PLOS ONE.
