Influência da imersão nas respostas cardiorrespiratórias em repouso Influence of immersion on resting cardiorespiratory responses

Diversos benefícios nos componentes da aptidão física podem ser adquiridos com a prática de exercícios aquáticos. Além disso, a água proporciona um ambiente para a prática de exercícios com reduzido impacto nos membros inferiores e maior ou menor sobrecarga cardiorrespiratória, de acordo com os movimentos realizados. Porém, tais exercícios podem produzir respostas fisiológicas diferentes daquelas ao ar livre, visto que ocorrem alterações fisiológicas importantes durante a imersão, sendo importante a compreensão das mesmas em repouso para melhor prescrição nesse meio. O presente estudo tem como objetivo revisar estudos sobre o comportamento da frequência cardíaca e do consumo de oxigênio durante a imersão em repouso e compreender os fatores que influenciam nesse comportamento. Várias pesquisas indicam que a frequência cardíaca de repouso é reduzida com a imersão em meio aquático, porém, é importante salientar que fatores tais como temperatura da água, posição corporal, profundidade de imersão e frequência cardíaca inicial podem minimizar ou maximizar tais respostas. Os estudos que abordaram as respostas de consumo de oxigênio não são conclusivos; entretanto, ao contrário da frequência cardíaca, os mesmos indicam semelhante ou maior resposta durante a imersão em repouso. Assim, pode-se concluir que, devido às alterações cardiorrespiratórias verificadas com a imersão em ambiente aquático, a prescrição de exercícios nesse meio deve ser diferenciada daquela para exercícios em ambiente terrestre.<br>Several benefits in the physical fitness components can be acquired with the practice of aquatic exercises. Moreover, water provides an environment for the practice of exercises with reduced impact on lower limbs and major or minor cardiorespiratory overload, depending on the movements performed. However, such exercises can produce physiological responses different from those on dry land, since important physiological alterations occur during immersion, being important to understand them at rest for better prescription in this environment. The present study has the purpose to review studies about the heart rate behavior and the oxygen uptake during immersion at rest and to understand the factors that influence in this behavior. Several investigations indicate that heart rate at rest is reduced with immersion in aquatic environment; however, it is important to highlight that factors such as water temperature, body position, immersion depth and initial heart rate may minimize or maximize such responses. The studies which approached the oxygen uptake responses are not conclusive; however, contrary to heart rate, the same ones indicate similar or greater response during immersion at rest. Thus, it can be concluded that, due to the verified cardiorespiratory alterations with immersion in aquatic environment, the prescription of exercises in this environment must be differentiated from exercises on dry land

Efeitos do repouso e do exercício no solo e na água em hipertensos e normotensos Effects of rest and exercise on ground and in water in hypertensive and normotensive patients

Este estudo visou avaliar o efeito do repouso e do exercício, realizados no solo e na água, sobre a frequência cardíaca (FC), pressão arterial sistólica (PAS) e diastólica (PAD) e o volume de diurese em indivíduos hipertensos e normotensos. Foram analisados 20 indivíduos divididos em dois grupos, normotensos (GN, n=8) e hipertensos (GH, n=12). Em ambos foram realizados quatro protocolos distintos, dois de exercícios e dois de repouso, no solo e na água. A PAS, PAD e FC foram mensuradas durante repouso e aos 30, 60 e 90 minutos após cada protocolo. O volume de diurese foi corrigido pelo peso corporal e coletado 30 minutos após cada protocolo. No GH, o protocolo de exercício no solo promoveu redução média de 16,5±3,7 mmHg (p=0,01) da PAS aos 90 minutos pós-exercício. No GN, o protocolo de repouso na água promoveu redução média de 14 bpm (p<0,01) da FC e o volume de diurese foi maior quando comparado aos protocolos realizados no solo (p<0,01). Portanto, a imersão desencadeou bradicardia e aumento do volume de diurese no GN. Não houve efeito hipotensor significativo nos protocolos realizados na água em ambos os grupos. Os resultados sugerem que uma sessão de exercício físico no solo com duração de 45 minutos, em intensidade submáxima, provoca redução da PAS em indivíduos hipertensos.<br>The aim of this study was to assess the effect of rest and exercise, accomplished on the ground or in water on the heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) and the volume of diuresis in hypertensive and normotensive individuals. Twenty individuals were analyzed and divided into two groups, normotensive (GN, n=8) and hypertensive (GH, n=12). Both groups accomplished four distinct protocols, two protocols of exercise and two protocols of rest on the ground and in the water. The SBP, DBP and HR were measured at rest and at 30, 60 and 90 minutes after each protocol. The volume of diuresis was corrected for the body weight and collected 30 minutes after each protocol. In the GH, the exercise protocol on the ground caused an average reduction of 16.5±3.7 mmHg (p=0.01) in SBP at 90 minutes post-exercise. In the GN, the protocol of rest in the water caused an average reduction of 14 bpm (p<0.01) in HR and the volume of diuresis was increased when compared with the protocols accomplished on the ground (p<0.01). Therefore, the immersion triggered bradycardia and increase in volume of diuresis in the normotensive group. There was no significant hypotensive effect in the protocols performed in water in both groups. The results suggest that an exercise session on the ground during 45 minutes in submaximal intensity causes a reduction in SBP in hypertensive subjects

Water-based training enhances both physical capacities and body composition in healthy young adult women

PURPOSE: The purpose of this study was to determine the effectiveness of a 9 weeks aquatic training program on aerobic capacity, muscle strength, flexibility, balance and body composition in 34 healthy young adult women. METHODS: Five typical water based exercises (WE) of known intensity were utilized during the classes; intensity ranged from “moderate” to “hard” according to ACSM criteria (RPE range 12–14). RESULTS: The group physical activity level and food intake were not significantly different before and after training. A significant decrease for the skin folds sum (−4.6 %) and for %fat mass (−3.8 %) calculated according to skin folds technique was found after training. DXA regional data showed a significant increase in the fat-free mass of arms (2.4 %) and trunk (0.9 %). According to the Astrand step test, the training program led to an increase of estimated maximal oxygen uptake (14.9 %) and a decrease in sub-maximal Heart Rate (−6.9 %). A significant change in the majority of the physical capacities tested was found: abdominal and upper body muscular endurance (21 and 36 %, respectively), leg flexors and extensors maximal strength (12 and 8 %, respectively) as well as balance (34 %) all improved after training (p < 0.05). CONCLUSIONS: A training program based on WE of known intensity and tailored to the ACSM recommendations can significantly improve cardio respiratory fitness, muscular endurance, strength, balance and some aspects of body composition in active young adult women