Abstract
Exercise training is known to reduce CVD risk factors; however, in tactical populations, like veterans and firefighters, the effects of different forms of exercise such as tactical circuit training (CT) or conventional resistance training (RT) is unclear. Thus, the purpose of this study was to compare changes in various CVD risk measures after 4-week tactical CT or RT programs. Thirty-seven firefighters (20 CT, 17 RT), 35% of whom were veterans, participated. Pre- and post-intervention measures included body fat (BF%), carotid artery intima media thickness (IMT), central and brachial BP, and indices of arterial stiffness (augmentation index, Aix@75), myocardial oxygenation (subendocardial viability ratio, SEVR), and endothelial function (flow-mediated dilation, FMD). Estimation of maximum oxygen consumption (VO(2peak)) for aerobic fitness, balance, muscular endurance, and strength were also compared. For the clinical laboratory values, there were no between group differences and the only within group change was found in triglyceride levels. Tactical CT lowered triglyceride levels by 24.2% (P < 0.05). Only tactical CT exercise lowered BP. Both brachial (4.6% reduction) and central (4.4 % reduction) systolic and diastolic SBP and DBP decreased with CT (all P ≤ 0.01). After training we found improvements in FMD and SEVR with tactical CT only. Percent FMD increased by 28.7% (P < 0.01) while SEVR increased by 4.4% (P < 0.05) in the tactical CT group. Fitness improved in both cohorts (P < 0.05). These data suggest that 4 weeks of a CT program improves several CVD-risk factors and may be more beneficial.