Aerobic fitness predicts the air consumption time in the self-contained breathing apparatus during physical task of firefighters / La capacidad aeróbica predice el tiempo de consumo de aire de un equipo de respiración autónoma durante tareas físicas de bomberos / Aptidão aeróbia prediz o tempo de consume de ar no equipamento autônomo de proteção respiratória durante tarefa física de bombeiros

Objective: The aerobic fitness on predicting firefighters' air consumption time from self-contained breathing apparatus (T_SCBA) during physical task was investigated. Methods: Twenty firefighters were divided in two groups: G1 (n=10; 28.0±3.1 years) for the generation of a predictive equation of T_SCBA and G2 (n=10; 25.4±2.3 years) for the validation of the predictive equation. The groups completed two performance tests in separate days: 1) maximal 1600m running in order to determine mean velocity (1600mV) and maximal heart rate; 2) submaximal running/walking at intensity between 88-92% of the maximal heart rate. In second test, the firefighters were equipped with protective clothing (boots, gloves, cape, helmet and balaclava) and the self-contained breathing apparatus. The T_SBCA (corresponding to 1020 liters of pressurized air), blood lactate, heart rate and rate of perceived exertion were measured. Results: The linear regression of G1 (T_SCBA vs. 1600mV) resulted in the following predictive equation: T_SCBA= 0.0442*1600mV (m.min-1) + 4.5029 (r= 0.85; SEE= 0.73; p<0.001). When analyzing in G2, the measured and predicted T_SCBA using the equation generated in G1, no significant differences were found (T_SCBA measured= 15.5±2.5 min vs. T_SCBA predicted= 14.7±0.4 min; p=0.21). High correlation (r=0.95; SEE= 0.79; p<0.001) and agreement of the difference of the means (0.9 min [-3.1/+4.8]) were also found. Conclusion: Aerobic fitness presented high correlation with T_SCBA. In addition, the proposed predictive equation was considered valid to estimate T_SCBA during physical task of firefighters, which can have practical application in the labor activity of this population

Objetivo: Investigar la capacidad aeróbica como factor de predicción del tiempo de consumo de aire de un equipo de respiración autónoma (T_ERA) durante la realización de tareas físicas de bomberos. Método: Veinte bomberos se dividieron en dos grupos: G1 (n=10; 28.0±3.1 años) para la generación de la ecuación predictiva de T_ERA y G2 (n=10; 25.4±2.3 años) para la validación de la ecuación predictiva. Los grupos completaron dos test en días separados: 1) 1600m de carrera máxima para determinar la velocidad media (1600mV) y la frecuencia cardiaca máxima; 2) carrera submáxima/caminata a una intensidad entre el 88-92% de la frecuencia cardiaca máxima. En el segundo test, los bomberos usaron su ropa de protección (botas, guantes, capa, casco y pasamontañas) y el equipo de respiración autónomo. Se midió: el T_ERA (correspondiente a 1020 litros de aire presurizado), el lactato en sangre, la frecuencia cardiaca y el índice de esfuerzo percibido. Resultados: La regresión lineal del G1 (T_ERA vs. 1600mV) resultó en la siguiente ecuación predictiva: T_ERA= 0.0442*1600mV (m.min-1) + 4.5029 (r= 0.85; EEE= 0.73; p<0.001). Cuando se analizó el G2, no se encontraron diferencias significativas entre el valor de T_ERA medido y el calculado usando la ecuación generada con el G1 (T_ERA medido= 15.5±2.5 min vs. T_ERA calculado= 14.7±0.4 min; p=0.21). Se encontró una alta correlación (r=0.95; EEE= 0.79; p<0.001) y concordancia con la diferencia de las medias (0.9 min [-3.1/+4.8]). Conclusión: La capacidad aeróbica presentó una alta correlación con el T_ERA. Además, la ecuación de predicción propuesta se consideró válida para estimar el T_ERA durante tareas físicas de bomberos, lo que tiene grandes aplicaciones prácticas en la labor de esta población

Objetivo: Investigar a aptidão aeróbia na predição do tempo de consumo de ar durante tarefa física de bombeiros a partir do equipamento de proteção respiratória (T_EPR). Método: Vinte bombeiros foram divididos em dois grupos: G1 (n=10; 28.0±3.1 anos) para geração da equação preditiva do T_EPR e G2 (n=10; 25.4±2.3 anos) para validação da equação preditiva. Os grupos realizaram dois testes de desempenho em dias distintos: 1) 1600m de corrida em máxima intensidade para determinar a velocidade média (Vm1600) e a frequência cardíaca máxima; 2) corrida/caminhada em intensidade submáxima entre 88-92% da frequência cardíaca máxima. No segundo teste, os bombeiros estavam equipados com roupa de proteção (botas, luvas, capa, capacete e balaclava) e equipamento de proteção respiratória. O T_EPR (correspondente a 1020 litros de ar pressurizado), lactate sanguíneo, frequência cardíaca e percepção subjetiva de esforço foram mensurados. Resultados: A regressão linear do G1 (T_EPR vs. Vm1600) resultou na seguinte equação de predição: T_EPR= 0.0442*Vm1600 (m.min-1) + 4.5029 (r= 0.85; EPM= 0.73; p<0.001). Quando analizado em G2, o T_EPR medido e predito a partir da equação gerada em G1, não foi encontrada diferença significante (T_EPR medido= 15.5±2.5 min vs. T_EPR predito= 14.7±0,4 min; p=0.21). Alta correlação (r=0.95; EPM= 0.79; p<0.001) e concordância na média das diferenças (0.9 min [-3.1/+4.8]) também foi encontrada. Conclusão: A aptidão aeróbia apresentou alta correlação com o T_EPR. Em adicional, a equação preditiva proposta foi considerada valida em estimar o T_EPR durante tarefa física de bombeiros, o que pode ter aplicação prática na atividade laboral dessa população

Twenty minutes of post-exercise hypotension are enough to predict chronic blood pressure reduction induced by resistance training in older women

AIM: This study investigated the correlation between post-exercise hypotension (PEH) and chronic blood pressure (BP) reduction in older women after a resistance training (RT) program. METHODS: Twenty-five older women (≥60 years) performed a RT program for 8 weeks, 3x/week consisting of 3 sets of 8-12 repetitions maximum in 8 exercises. Acute and chronic BP measurements were performed using automatic equipment, in which acute BP was measured before and after 10, 20, 30, 40, 50 and 60 min following the sixth exercise session, while chronic BP was measured pre and post-training. RESULTS: Significant decrease for systolic blood pressure (SBP) was observed after the intervention period, however, the diastolic blood pressure (DBP) did not change. To acute changes in BP, SBP decreased at all times after a single RT session, while DBP increased after 40 min. The reduction for SBP after a single RT session at baseline showed positive and significant correlations with the reductions in basal SBP observed after the 8 weeks of RT, the strongest correlations were observed at 20 min. A linear relationship between the magnitude of change in chronic SBP and the 20 min for acute SBP, and 30 min for acute DBP of post-exercise was observed. CONCLUSION: The results suggest that acute BP lowering after RT session is a reliable predictor of chronic BP response to exercise training, and 20 min of resting, after RT training, is enough to indicate chronic response of BP as this measure was highly associated with chronic BP lowering in older women.(AU)