Effects of Heart Rate Biofeedback, Sleep, and Alertness on Marksmanship Accuracy during a Live-fire Stress Shoot

On the job, law enforcement may be required to utilize lethal force to maintain personal or public safety. Officers' attention to detail, decision-making, and marksmanship accuracy (MA) may be impaired by reduced sleep, increased heart rate (HR), and breathing rate (BR). HR biofeedback (emWave, EW) may help mitigate these impairments. This study sought to determine the impact EW had on MA, stress shoot time-to-completion (TTC), HR and BR versus placebo (PLA). Ten activeduty police officers volunteered for this study. Officers completed two live-fire stress shoots on a 25-m gun range (i.e., familiarization, followed by EW, or PLA trials). MA was assessed as "hit, no-hit." HR and BR were monitored before, immediately after, and 20 minutes post-trial. Sleep was monitored during the entirety of the study. Dependent t-tests were conducted for MA and TTC. A 2x3 repeated-measures ANOVA was conducted for HR, BR, before, during, and after each trial. There were no statistical differences (EW vs. PLA) for: HR (128 ± 23 vs. 136 ± 14; p = 0.30), BR (19 ± 2 vs. 21 ± 2; p = 0.31), TTC (108.4 ± 11.2s vs. 111.6 ± 20.2s; p = 0.94; d = 0.21). Alertness (83.2 ± 9.5 vs. 77.9 ± 15.5), was not statistically significant EW vs. PLA (p = 0.32; d = 0.42). MA (81.4 ± 10.2 vs. 85.9 ± 12.9%) was not statistically significant EW vs. PLA (p = 0.95; d = 0.38). Sleep (7.4 ± 2.9h vs. 5.4 ± 1.7h) was not statistically significant EW vs. PLA (p = 0.13; d = 1.0). EW usage did not affect the physiological and marksmanship performance of officers during a live-fire stress shoot based on HR, BR, TTC, and MA while considering sleep quantity.