Introduction: Autonomic recovery is critical for tactical readiness. While structured breathwork enhances parasympathetic reactivation, it is unclear whether body composition indices such as percent body fat (%BF) or fat-free mass index (FFMI) influence acute recovery following maximal exertion. This study examined whether %BF or FFMI moderate post-exercise autonomic recovery in ROTC cadets.

Methods: Fifty-two cadets (age 20.0 ± 3 yrs; %BF 28.5 ± 7.7; FFMI 18.4 ± 2.8) completed a maximal rowing test and were randomized to box breathing (BB, n = 19), cyclic sighing (CS, n = 17), or spontaneous breathing (SB, n = 16) during a 3-min active recovery. HF-HRV was measured at baseline, 1–3 min, and 4–6 min post-exercise. HRR was calculated at 1 and 3 min. Repeated-measures MANOVA and %BF- and FFMI-adjusted MANCOVA were performed.

Results: A significant main effect of time was observed for HF-HRV (Pillai’s Trace = .934, F(2,48) = 339.86, p < .001). The Time × Group interaction reached significance in the FFMI-adjusted model (Pillai’s Trace = .190, F(4,96) = 2.52, p = .046). Time × %BF and Time × FFMI interactions were non-significant (p ≥ .271). Regression analyses showed BB and CS predicted higher HF-HRV at Post1 (R² = .193) and Post2 (R² = .224; p ≤ .017), whereas %BF and FFMI were not significant predictors. HRR demonstrated a main effect of time (p < .001) without group or body composition effects.

Conclusions: Structured breathwork enhanced post-exercise parasympathetic reactivation independent of %BF and FFMI. Body composition did not significantly influence acute autonomic recovery in this cohort.

Purpose: 

This study investigated the acute effects of two structured breathwork methods on autonomic recovery following maximal exertion.

Materials and Methods: 

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 (VO₂). 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.

Results: 

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, η²=0.89), group (F_(2,59) = 8.20, P < 0.001, η²=0.22), and time × group interaction (F_(4,118) = 3.54, P = 0.009, η²=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, η²=0.36).

Conclusions: 

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.

Body composition and performance has long been components analyzed in tactical athletes within organizations assessing rates of obesity and their ability to perform duties. Many times, individuals within these organizations fall short of the standards set forth. Multiple methods of decreasing body composition and increasing performance present when tactical athletes fall out of regulations. Tactical athletes train at high intensities and most of the time for long durations. Thus, fad diets such as caloric deficits and Intermittent Fasting (IF) were investigated to decide if training in a fasted state improved performance or assisted in decreasing body composition. The research method I used was a search of literature relating to IF, calorie deficits and military caloric expenditure. The search yielded multiple sources related to body composition and performance, although selected articles closely related to tactical athletes and training methods commonly used. The findings of the study presented that fasted training at low intensities does improve body composition, while high intensities don’t improve either body composition or performance. Conclusions showed tactical athletes can perform fasted training, although high and low intensities must be varied to accommodate the energy intake for best results, resulting in the need for adequate training on this topic.