HRR from the 1st to 5th min post-exercise negatively correlated with parasympathetic modulation in resting orthostatic, but showed no correlation in supine position. At the 3rd and 5th min, a positive correlation with combined sympathetic-parasympathetic modulation in both positions was observed.

BACKGROUND: Firefighters' activities require constant adjustments of the cardiovascular system with cardiac autonomic function (CAF) playing an important role. Despite the crucial role of CAF in regulating stress response, little is known about firefighters' CAF. OBJECTIVE: We aimed to characterize the resting on-duty and off-duty CAF of male firefighters, in association with cardiorespiratory fitness (CRF). METHODS: We evaluated 38 firefighters in an on-duty rest condition and 26 firefighters in an off-duty laboratory-controlled condition. CAF was addressed by means of heart rate variability (HRV). We compared HRV measurements between CRF categories (<12METs vs ≥12METs). Wilcoxon, Mann-Whitney texts and Spearman correlation were used and General Linear Model was applied for age and BMI adjustments. RESULTS: Firefighters' resting CAF is characterized by a predominant sympathetic modulation and a large inter-individual dispersion in all HRV indices, in both groups. We found a positive correlation between a higher CRF, the overall CAF and the higher parasympathetic activity (p < 0,03). Firefighters with CRF ≥12 METs showed a higher parasympathetic modulation. CONCLUSIONS: Firefighters' resting CAF is characterized by a predominant sympathetic modulation and a large interindividual dispersion in all HRV indices, in both groups. Our results support mandatory physical training focused in improving firefighters' CAF as a cardiopretective effect.

IntroductionHypertension is the most prevalent modifiable risk factor with a high prevalence among older adults. Exercise is a nonpharmacological treatment shown to benefit all patients with hypertension.ObjectiveThis study examined the effects of a 14-week moderate intensity resistance training program (RT) on the maintenance of blood pressure and hand grip strength during an extended detraining period in elderly hypertensive women.MethodsTwelve hypertensive sedentary elderly women completed 14 weeks of whole body RT at a moderate perceived exertion following a detraining period of 14 weeks.ResultsFollowing the training period, participants demonstrated an increase in absolute hand grip strength (P=0.001), relative hand grip strength (P=0.032) and a decrease of systolic (P=0.001), diastolic (P=0.008), and mean blood pressure (P=0.002) when compared to pre-exercise values. In addition, these effects were sustained after 14 weeks of detraining.ConclusionResistance training may be a valuable method to improve muscular strength and blood pressure in elderly people with benefits being maintained up to 14 weeks following training cessation.

Bradycardia and higher oxygen uptake were found in association with unaltered cardiac autonomic modulation in elite mountain bikers athletes in supine and orthostatic positions, compared to active non-athletes. This bradycardia was not dependent on distinctive resting autonomic modulation. Intrinsic adaptation of sinus node and/or a peculiar state of autonomic adaptation to this exercise can be possible mechanisms.

Several resistance training methods (RTM) have been developed in order to manipulate physiological stimuli and obtain better results with training. The purpose of this study is to compare the metabolic and mechanical responses among seven different RTM reported in the literature. The RTM were compared with regard to blood lactate, time under tension (TUT) and total loading (TUT x load) in recreationally trained young men. The RTM tested were 10RM (TEN), super-slow (SL), functional isometrics (FI), adapted vascular occlusion (VO), 6RM (SIX), forced repetitions (FR) and breakdowns (BD). All RTM produced significant increases in blood lactate, with no difference among them. The BD method elicited higher TUT and total loading compared to the other RTM tested.