The Effect of Aerobic Fitness on Psychological Stress as Measured by Heart Rate Response During Academy Training in a Custody Assistant Recruit Population

INTRODUCTION: Custody Assistants (CAs) have a job that often will subject them to high levels of psychological stress. During performance of daily job tasks, CAs may encounter high anxiety situations and may need to make effective decisions under stressful conditions. One of the goals of academy training is to prepare CA recruits for stressful situations by subjecting them to high levels of psychological stress. Previous research has shown that aerobic fitness can potentially moderate the effects of high anxiety and stressful situations. Given the importance of decision making and stress tolerance in this population, research is needed to determine the physiological response to situations of high stress. PURPOSE: To determine the effect of aerobic fitness on the physiological response of CAs to a high stress situation on the first day of academy training using heart rate (HR) data. METHODS: Retrospective analysis was performed on data from a one CA class of 26 recruits (15 males,11 females). The session was designed to elicit an elevated stress response via verbal commands from training staff, with limited physical activity. HR data were gathered using HR monitors, and categorized (relative to age-predicted maximum HR; HRmax) according to American College of Sports Medicine (ACSM) guidelines (very light: <57% HRmax, light: 57%-63% HRmax, moderate: 64%-76%, HRmax, vigorous: 77%-95% HRmax, very vigorous: >95% HRmax). Recruits were grouped into fitness ability levels based on their estimated maximal aerobic capacity from a 2.4-km run relative to ACSM general population age norms (Superior, Excellent, Good, Fair, Poor, Very Poor). Superior and Excellent categories were collapsed into High Fit (HF; n = 4); Good and Fair were combined into Moderate Fit (MF; n = 8); and Poor and Very poor were considered Low Fit (LF: n = 14). A one-way ANOVA (p < 0.05) was used to assess the differences in time spent in the various HR zones between the three fitness groups. RESULTS: The total time for the session was 75 minutes. There were no significant between-group differences on the time spent in the different HR zones or the percentage of total time spent in the different zones. Collectively, the three groups spent the largest percentage of total training time in the vigorous zone (HF = ~61.37%; MF = ~58.81%; LF= ~50.99%). This equated to 45, 44, and 33 minutes spent at a vigorous intensity for the HF, MF, and LF groups, respectively. CONCLUSIONS: These data suggested that a psychological stress session provided a similar intensity to a vigorous aerobic training session (as defined by ACSM). Aerobic fitness did not seem to significantly attenuate the physiological response to stress in this CA class, contrary to previous research. One potential reason for this is that 14/26 recruits (53%) were classified as having poor or very poor aerobic fitness. Individual recruits are seldom the sole recipient of consequences due to any mistakes made within the group. This may have meant that poorer fit recruits made errors that impacted the HR response of HF recruits. PRACTICAL APPLICATIONS: Law enforcement agencies should be aware of the aerobic fitness of their CA recruits, which was generally poor in this class. Further research is needed with a larger sample as the current class was relatively homogenous in its physical ability. In addition, more research is necessary to analyze specific decisions made under stress in relation to physical fitness.