Changes In Heart Rate And Heart Rate Variability Across A Law Enforcement Training Academy

Training for law enforcement cadets (LECs) targets physical fitness, but additional sleep, nutrition, recovery, and stress management education could benefit their performance. PURPOSE: To examine the effect of holistic education on LECs’ heart rate (HR) and heart rate variability (HRV) during fitness testing at the beginning (PRE) and end (POST) of a 10-week training academy. METHODS: Sixty-seven LECs (12 females, 55 males; age = 39 ± 8.0 years; BMI = 30.7 ± 8.4 kg/m2) were randomized into control (CON) or experimental (EXP) groups. The EXP group was given five lectures on improving sleep, nutrition, recovery, and stress management. LECs completed their fitness test PRE and POST, while wearing a chest HR monitor. HR variables included HRmax and HRmean. HRV variables included standard deviation of normal-to-normal (SDNN), root mean square successive difference (RMSSD), and low frequency (LF), high frequency (HF), and total power (TP). Data were sampled during the fitness test and at 1-min intervals for 10-min after the test. Linear mixed models were used to evaluate group, time, and group-by-time as fixed effects; subject and time after the test as random effects; and age, BMI, sex, and fitness test completion time as covariates (α-level = 0.05). RESULTS: There was only a significant group-by-time interaction for HRmean, whereby EXP had a larger decrease from PRE (139.46 ± 22.69 bpm) to POST (134.76 ± 21.49 bpm) than CON (PRE = 140.85 ± 22.69 bpm, POST = 138.74 ± 22.69 bpm) (p = 0.043). There were also significant main effects for group, where CON had higher HRmax (CON = 147.24 ± 23.39 bpm, EXP = 144.76 ± 24.10 bpm; p = 0.026), but lower LF (CON = 35.44 ± 157.37 ms2, EXP = 45.85 ± 170.54 ms2; p = 0.022) and TP (CON = 7.05 ± 27.94 ms2, EXP = 9.05 ± 31.38 ms2; p = 0.014). Finally, SDNN (PRE = 5.45 ± 4.52 ms, POST = 6.63 ± 5.79 ms, p < 0.001), LF (PRE = 31.24 ± 138.77 ms2, POST = 53.63 ± 191.59 ms2, p < 0.044), and TP (PRE = 42.33 ± 168.69 ms2, POST = 72.93 ± 238.59 ms2, p < 0.036) significantly increased from PRE to POST testing. No HRV measures had significant group-by-time interactions (p > 0.05). CONCLUSION: Both groups reduced their HRmean across the training academy, but EXP had larger improvements. Teaching LECs how to improve their sleep, nutrition, recovery, and stress management in the academy may reduce HR during physically demanding tasks. Supported by: BWC- Bureau of Workers' Compensation