New Study Tracks Officers’ Response to Stress During Calls for Service

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It is widely understood that the body can automatically prepare us to respond to threats.  Not just actual threats, but those that are perceived or merely expected.  Ideally, when this process is engaged, the nervous system is activated and we benefit from heightened senses, faster decision-making, improved mental function, and increased strength.

But when this acute stress response is “maladaptive” or prolonged, our health can suffer over the long term.  And in the short term, under extreme stress—attention, perception, decision-making, and even physical performance can be severely impaired. 

For those committed to public safety, learning to recognize, manage, and operate under extreme stress is critical.  For the police, that process begins by understanding when and how they experience stress.

In a recent study, Simon Baldwin (PhD Candidate and Force Science Advanced Specialist) and a team of researchers from Carleton University’s Police Research Lab (Ontario, Canada), provided valuable insight into these important questions.  Specifically, researchers studied how frequently police officers experienced “physiological stress responses” during a shift, whether those responses changed during the distinct phases of a call, and whether the priority of a call or other factors (e.g. arrest, use of force) affected physiological arousal. 

Intuitively, readers might expect that an officer’s experience and training would improve their response to stress. Researchers examined these factors as well—with important findings.

The Study

Using an officer’s heart rate as a measure of stress response, researchers attached pulse monitors with GPS capability to track 64 officers over various shifts.  To help distinguish between heart rate resulting from physical exertion and heart rate resulting from psychological stress, the researchers attached foot-mounted “stride sensors” to the officers.  When combined with the GPS, these stride sensors provided researchers with important speed measurements.

After collecting data from 754 calls for service, the researchers examined the participants’ heart rates throughout the phases of the calls (dispatch, travel, arrival, and encounter).  Additionally, the calls were categorized and analyzed by priority level (routine, urgent, very urgent), type (e.g. shots fired, assault in progress, suicidal person, etc.), and incident factors (e.g. arrest, use of force, weapon presence).

Finally, the relevant training and experience of the officers was considered for any impact on the physiological stress response (as measured by heart rate variability).

Notable Results

The researchers noted significant heart rate reactions during the calls for service.  More significant reactions corresponded to the higher priority calls—with increased arousal noted as the officers moved through the phases of the call; beginning with the dispatch, continuing through travel, and peaking at the encounter.

Readers who remember their first months of police work, may not be surprised by the finding that dispatch alone caused an increase in heart rate.  Training officers may recall recruits who experienced emotional responses triggered upon hearing the description or type of call.  These reactions were likely noted well-before officers arrived at the scene where they could assess actual threats.

As might be expected, the study also found that the presence of weapons, carrying out of arrests, and drawing firearms also resulted in notable heart rate increases.  Researchers were able to collect vital data and graphically display the effect of these factors during real-world interactions—including a call for service, during which an officer drew his rifle and ultimately deployed his taser on an armed subject.

Finally, researchers looked at the impact of training and experience on the stress responses identified in this study.  They found that the officers’ demographic (e.g. age, sex, etc.), experience, and operational skills training did not significantly impact (or mitigate) stress induced heart rates.

Dr. Bill Lewinski, executive director of the Force Science Institute, had this to say: “Simon’s observation that physiological responses were triggered across the range of experience was consistent with what we’ve seen in other research.  For example, in sports, we’ve seen that pre-event arousal is impacted by the meaning that is assigned to the event.  Both novice and elite athletes can experience pre-competition anxiety when they view the outcome as important.  That said, we’ve seen world-class performance from athletes and law enforcement officers operating with extremely high heart rates.  There continues to be mounting evidence that the ability to recognize, manage, and confidently perform under the effects of physiological arousal remains a key to optimum performance.”

The Carleton University researchers also recognized previous studies in which officers’ experience and training were shown to improve decision-making processes, attention, control, shot accuracy, and cue recognition1. Given these findings, the researchers encouraged further examination into the interaction between stress, training, and performance.

A Recommended Read

Simon Baldwin is among the growing ranks of Force Science Advanced Specialists at the intersection of science and police practice. With this latest study, his team of researchers have provided important insights for officers training and preparing for exceptional performance and increased resilience during high-stress encounters.

“While most are familiar with the concept of ‘fight-or-flight,’ this research aims to provide officers with a better understanding of what this threat response actually looks like, factors that impact it, and how frequently it occurs in the general duty policing context. Our hope is the research will improve self-awareness and promote the importance of evidence-based training methods that develop stress resilient skills.”

Simon Baldwin

The full report of this latest research is titled Stress-Activity Mapping: Physiological Responses During General Duty Police Encounters2 and can be accessed for free.  It not only advances the study of officer resiliency but provides an excellent primer on the terminology and processes involved in physiological stress response.  Readers are encouraged to consider the full report.

Questions, comments, and recommendations for further research in this area can be sent to Simon Baldwin.

  1. Vickers, J. N., and Lewinski, W. J. (2012). Performing under pressure: Gaze control, decision making and shooting performance of elite and rookie police officers. Hum. Mov. Sci. 31:16. doi: 10.1016/j.humov.2011.04.004 []
  2. Baldwin S, Bennell C, Andersen JP, Semple T and Jenkins B (2019) Stress-Activity Mapping: Physiological Responses During General Duty Police Encounters. Front. Psychol. 10:2216. doi: 10.3389/fpsyg.2019.02216 []
3 Responses
  1. Robert A O'Connor

    Thanks for this valuable information. Although I am retired, I try to stay informed as a concealed carrier and father of a serving LEO and training deputy. This info is valuable for anyone who was or is in service, and adds to the body of knowledge for all of us interested in the outcomes of the interaction between law enforcement and the public.

    Bob O’Connor MSCJ
    Retired Special Agent Supervisor, Florida Dept of Law Enforcement

  2. Chris Leblanc

    Interesting – but it seems the study is at first saying that training and experience is NOT a factor in regulating heart rate during high risk/high threat events.

    Granted it said that frequency or recency or the kinds of training wasn’t measured (some training is after all better than others), but are we to gather from this study simply that certain people – regardless of age, experience, training, or training type – just handle the heart rate spikes better than others and are able to make better decisions when their HR is spiking? We all know that some cops react much better under stress than others.

    Later it seems to be pointing to other studies saying that certain stress-based training does show results in reducing arousal related to heart rate spikes….so what to make of it?

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