Effectiveness of Structured Breathwork Interventions on Heart Rate Variability and Heart Rate Recovery Following Maximal Exertion in Tactical Athletes.

Abstract

This study investigated the acute effects of two structured breathwork methods on autonomic recovery following maximal exertion. A randomized control trial was conducted with 62 cadets (44 males and 18 females) assigned to three distinct groups: box breathing (BB), cyclic sighing (CS), or spontaneous breathing control. Participants performed a graded exercise test to assess maximal oxygen consumption (VO 2 ). High-frequency heart rate variability (HF-HRV) and heart rate recovery (HRR) were collected to evaluate autonomic recovery and parasympathetic reactivation. HF-HRV was analyzed at three time points: baseline (Pre), 1-3-min postexercise recovery (Post1), and 4-6-min postexercise (Post2). HRR was measured at 1- and 3-min intervals, analyzing reductions from peak heart rate captured at VO 2max . All analyses were evaluated using a 3 (group) × 3 (time) mixed-design repeated-measures analysis of variance. All groups were comparable in age, weight, height, and body mass index (21 ± 3 yr; 77.4 ± 15.4 kg; 173.1 ± 9.0 cm; 25.7 ± 4.0 kg·m -2 , respectively). HF-HRV revealed significant main effects for time ( F(2,118) = 465.01, P < 0.001, η 2 =0.89), group ( F(2,59) = 8.20, P < 0.001, η 2 =0.22), and time × group interaction ( F(4,118) = 3.54, P = 0.009, η 2 =0.21). Both the CS and BB groups had greater increases in HF-HRV from Post1 to Post2 when compared to spontaneous breathing ( P = 0.001). HRR improved across all participants from 1- to 3-min postexercise with n group level differences ( F(1,59) = 33.51, P < 0.001, η 2 =0.36). Structured breathwork following maximal exertion significantly accelerated parasympathetic reactivation as reflected by HF-HRV. Both BB and CS offer a simple field-ready intervention aimed to enhance operational readiness for tactical populations through enhancing acute physiological recovery.