By use of the impedance noninvasive method, cardiac output (Q), stroke volume (SV), heart rate (HR), Heather index (HI), and systolic time interval (STI) values were studied in 17 subjects working at 25, 50, and 75% of their maximal oxygen uptake (Vo2 max) on a Monark bicycle. A significant increase in SV at each work load and a concomitant decrease in positive expiratory pressure (PEP), left ventricular ejection time (LVET), and PEP/LVET were observed. The linear regression equation at 75% Vo2 max between LVET and HR and SV confirms the close relationship between these parameters. The significa-t increase of the contractility index (HI) showing the stress response of the myocardium is clearly assessed. At 75% work load, its correlation with SV is low; but the high level of the correlation (r = 0.90) between HI and HR in the stress response. Consequently the changes in STI and HI provide valuable information on SV adjustment during calibrated effort responses. Consequently, the changes in STI and HI, the relationship between STI and SV, and the study of SV, HR, and Q provide valuable information about the adjustment of these parameters during calibrated efforts.

Flexibility training responses to distinct stretching techniques are not well defined, especially in the elderly. This study compared the flexibility of elderly individuals before and after having practiced hatha yoga and calisthenics for 1 year (52 weeks), at least 3 times/week. Sixty-six subjects (12 men) measured and assigned to 3 groups: control (n = 24, age = 67.7±6.9 years), hatha yoga (n = 22, age = 61.2±4.8 years), and calisthenics (n = 20, age = 69.0±5.8 years). The maximal range of passive motion of 13 movements in 7 joints was assessed by the Flexitest, comparing the range obtained with standard charts representing each arc of movement on a discontinuous and non-dimensional scale from 0 to 4. Results of individual movements were summed to define 4 indexes (ankle+knee, hip+trunk, wrist+elbow, and shoulder) and total flexibility (Flexindex). Results showed significant increases of total flexibility in the hatha yoga group (by 22.5 points) and the calisthenics group (by 5.8 points) (p < 0.01 for each) and a decrease in the control group (by 2.1 points) (p < 0.01) after one year of intervention. Between-group comparison showed that increases in the hatha yoga group were greater than in the calisthenics group for most flexibility indexes, particularly the overall flexibility (p <0.05). In conclusion, the practice of hatha yoga (i.e., slow/passive movements) was more effective in improving flexibility compared to calisthenics (i.e., fast/dynamic movements), but calisthenics was able to prevent flexibility losses observed in sedentary elderly subjects.

1. Dobutamine has been used to study the relationship between oxygen consumption (VO2) and oxygen delivery (DO2) in critically ill patients, but this has led to concerns that it could consistently increase VO2 in all patients. Although a direct thermogenic effect of the catecholamine has been primarily implicated in this increase in VO2, an increase in blood flow may contribute significantly by increasing the oxygen requirements of the heart and other organs such as the kidney and the liver. If this mechanism is predominant, it should also be observed when blood flow increases during the infusion of non-adrenergic agents. To separate the two mechanisms, we compared the effects of dobutamine with those of sodium nitroprusside on VO2/DO2 relationships in healthy volunteers. 2. Eight healthy volunteers received infusions of dobutamine at doses of 2, 4 and 6 μg min−1 kg−1 and nitroprusside at doses of 0.5, 1 and 2 μg min−1 kg−1 in an alternate order. 3. VO2 was determined by indirect calorimetry and cardiac output by electrical bioimpedance. Data were analysed by analysis of variance for repeated measurements and individual VO2/DO2 slopes were determined by linear regression. 4. VO2 increased more with dobutamine than with nitroprusside (from 138 ± 14 to 149 ± 20 ml min−1 m−2, P < 0.001, and from 131 ± 14 to 138 ± 17 ml min−1 m−2, P < 0.001, respectively). However, DO2 also increased more with dobutamine than with nitroprusside (from 531 ± 186 to 702 ± 274 ml min−1 m−2, P < 0.001, and from 523 ± 107 to 610 ± 122 ml min−1 m−2, P < 0.001, respectively). Individual VO2/DO2 slopes were similar with dobutamine and nitroprusside (6.5 ± 3.5 compared with 7.1 ± 4.6%, P not significant). 5. At the doses used, DO2 and VO2 increased more with dobutamine than with nitroprusside in healthy volunteers. However, the VO2/DO2 slopes were similar for both substances. Thus, an increase in VO2 is not exclusively observed with catecholamines. Studies of the effects of therapeutic interventions on oxygen-derived variables should report not only changes in VO2 but also VO2/DO2 slopes.

possibilidade de elevação da FC. A V E em GJ comportou-se de forma similar ao VO 2 e VCO 2 . Porém, para GI as constantes de tempo foram mais lentas, mais associadas à IE que os demais parâmetros. Conclui-se: a) pode existir uma constante comum para a chamada 'fase alática' da curva de recuperação do VO 2 e do VCO 2 , independentemente da IE e da idade; b) as diferenças entre GJ e GI podem dever-se às menores potência aeróbia máxima, termorregulação e eficá-cia do tampão respiratório nos idosos. RESUMOSabe-se pouco sobre os efeitos do envelhecimento na recuperação pós-esforço (RP). O estudo observou a RP em 15 idosos (GI, idade = 61 ± 1 anos) e 15 jovens (GJ, idade = 22 ± 2 anos) após atividades de três intensidades (IE) em cicloergô-metro. Realizaram-se testes máximos, com incremento de 30W/min para GJ e de 25W/min após detecção de steadystate para GI. Posteriormente, os grupos pedalaram a 40% e 75% da carga máxima, respectivamente, 25 e 15 minutos. Foram acompanhados VO 2 , VCO 2 , V E e FC nos primeiros 15 minutos da RP nas três IE. O tratamento dos resultados compreendeu: a) teste de ajustamento das curvas experimentais a equações com uma ou duas exponenciais; b) cálculo do valor dos componentes para a equação mais ajustada; c) análise das constantes extraídas. Os desvios de ajustamento foram inferiores para uma curva de duas exponenciais, definida por integral de tempo na forma A/α +B/β. A/α designa a componente rápida da recuperação e B/β a lenta. Quando comparados os grupos, GI mostrou constantes maiores que GJ, evidenciando recuperação mais lenta nas duas fases. Subdividindo os componentes, em GI e GJ as constantes de velocidade de recuperação rápida (1/α) para VO 2 e VCO 2 foram semelhantes nas três IE, enquanto para a constante lenta (1/β), os valores para GI indicaram maior dependência em relação à carga. A recuperação da FC revelou-se extremamente dependente da IE para GJ. Para GI isso foi menos evidente, talvez

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