When your patients present with a low resting heart rate, prescribe caffeine. And hide the silverware.
In what was news to us, lower autonomic arousal is apparently “a well-known correlate” of criminal activity and other risk-taking behaviour in men.
A recent Swedish study set out to discover if the same was true for women.
Using medical data collected from over 12,000 female voluntary military conscripts and linking it with data from the National Crime Register for up to 40 years post-medical test, researchers found that resting heart rate, and to a lesser extent systolic blood pressure, were associated with criminal convictions.
Female conscripts with a lower resting heart rate (≤69 BPM) had an increased risk of around 35% for any criminal conviction and for non-violent criminal conviction compared with those with the highest resting heart rate (≥83 BPM). The relationship between heart rate and violent convictions was insignificant, likely due to insufficient statistical power (i.e. there weren’t very many).
They also found that women with a higher resting heart rate were more likely to be unintentionally injured – defined as inpatient and outpatient treatments and deaths due to accidental injuries (car crashes, falls) — a proxy for risk-taking behaviour.
Potential covariates including weight, height and physical energy capacity (how hard you can hit, how fast you can run) didn’t affect the association between heart rate and incidence of criminal activity or accidental injury, which the authors said indicates that resting heart rate “contributes uniquely to the prediction of these outcomes among female conscripts”.
The authors advanced two theories as to why these outcomes may be related to a low resting heart rate.
The first is fearlessness theory, which says that a low heart rate reflects fearlessness, which may increase the risk of sensation-seeking behaviours, potentially including criminal offending.
The other is stimulation-seeking theory, which suggests that a low heart rate is an “unpleasant physiological state”, relieved by risk-taking behaviour to up the beat to more optimal levels. But yeah, coffee does that too, so, you know, take your pick.
Due to the rare nature of the outcomes – fewer than 1% of the cohort had a criminal conviction or suffered an accidental injury – the researchers were unable to conduct analyses stratified on the severity of the crime.
However, the fact that zombies have a heart rate of zero and crime severity rating of 10/10 (which is a totally made-up rating scale but seems reasonable for homicide) tells us all we need to know there.
So, while the high cost of a coffee is criminal, it may just save you from a life of crime.
Send story tips that get our hearts racing to penny@medicalrepublic.com.au
