Frequently asked questions

Code 4 Pro and its sister company Provicta have conducted several studies over the last five years and published a scientific research paper:
James, L., Goldstein, M.S., Lecy, P. and Mase, S. (2021), "Testing the impact of physiological stress response on police performance during critical job tasks", Policing: An International Journal, Vol. 44 No. 3, pp. 405-417.
Introduction: To add to the existing body of knowledge on the relationship between stress and job performance in policing, we monitored police officers' physiology using Hexoskin shirts while they responded to simulated scenarios. Our aims were (1) to determine whether an individualized physiological stress profile – a combination of heart rate, heart rate variability, sympathetic nervous system index and parasympathetic nervous system index – could be developed for each participant; (2) to investigate the association between physiological stress and scenario performance and (3) to pilot test an intervention for decreasing physiological stress in real time. We found that it was possible to individualize physiological stress profiles for each participant that alerted us when the participant was becoming stressed. We also found that physiological stress was significantly and negatively/inversely associated with scenario performance.
The Code 4 Pro app displays information in three areas of the home page:
  1. Circle: Two values that are updated once or more each second
    1. Current heart rate
    2. Heart Rate Variability
  2. Heart Rate Chart: each bar represents the average heart rate in a one minute interval
  3. Compound Stress Chart: paired with the Heart Rate chart, it denotes stress in each one minute interval. The height of the bar represents the HRV average. The color of the bar represents the stress during that interval:
    1. Green: little to no stress
    2. Yellow: moderate stress
    3. Red: maximum stress
Code 4 Pro uses a unique protocol to protect user privacy and ensure that data will be kept private. Check out the privacy policy here.
From the sensor, we collect heart-related data: inter beat intervals (IBI), or the time in milliseconds between each heartbeat. From the phone, we collect motion-related data: distance traveled and instantaneous motion from the 3-axis accelerometer and the 3-axis gyroscope. As more data is collected and analyzed, the better our A.I. models can provide insights into the user’s stress profile.
Several other companies collect heart rate data and calculate HRV, including fitness technology companies that collect and calculate HRV daily or as often as every five minutes. It's a massive task to collect data and calculate HRV more frequently, putting a strain on computer resources. Code 4 Pro has developed the technology to collect HRV data every second, enabling the use and display of instantaneous stress measurement. This level of speed and scaling is important, as stress can develop within seconds and fade just as quickly.
Green = the lowest level of stress, when the mind and body are in sync. A low level of stress is optimal from a performance perspective.
Yellow = moderate stress. At the low end of the yellow range, there is some strain on the mind’s regulatory mechanisms; at the higher end, those same regulatory mechanisms become overstrained..
Red = the highest level of stress, when the sympathetic nervous system (“fight or flight”) is in control. When under stress, the individual’s regulatory systems are depleted; at the higher end of the red range, the individual experiences stress-adaptation failure, where the mind has no say in the body’s actions..
Bar Height The bar height represents the average HRV in that one minute period. HRV has been proven to be a reliable indicator of stress both instantaneously as well as over time. Stress levels are inversely proportional to HRV levels – the lower the HRV, the higher the stress. Science tells us that those with higher HRV levels will make better decisions as their body is properly balancing parasympathetic reasoning vs. the “fight or flight” sympathetic impulses. Conversely, when HRV levels are low, it means their body is under stress, which can interfere with their performance in the field.

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