Age affects exercise-induced improvements in heart rate response to exercise.

The aim of the present study was to analyze the effects of age on cardiorespiratory fitness (CRF), muscle strength and heart rate (HR) response to exercise adaptation in women in response to a long-term twice-weekly combined aerobic and resistance exercise program. 85 sedentary women, divided into young (YG; n=22, 30.3 ± 6.2 years), early middle-aged (EMG; n=28, 44.1 ± 2.5 years), late middle-aged (LMG; n=20, 56.7 ± 3.5 years) and older (OG; n=15, 71.4 ± 6.9 years) groups, had their CRF, muscle strength (1-repetition maximum test) and HR response to exercise (graded exercise test) measured before and after 12 months of combined exercise training. Exercise training improved CRF and muscle strength in all age groups (P<0.05), and no significant differences were observed between groups. Exercise training also improved resting HR and recovery HR in YG and EMG (P<0.05), but not in LMG and OG. Maximal HR did not change in any group. Combined aerobic and resistance training at a frequency of 2 days/week improves CRF and muscle strength throughout the lifespan. However, exercise-induced improvements in the HR recovery response to exercise may be impaired in late middle-aged and older women.

Haemodynamic, metabolic and neuro-humoral abnormalities in young normotensive women at high familial risk for hypertension.

We analysed the haemodynamic, metabolic and hormonal status at rest and in response to exercise, in young normotensive women with two hypertensive parents (FH++; n=17; 25.1±4.8 years), one hypertensive parent (FH+; n=18; 24.9±4.1 years) and normotensive parents (FH-; n=15; 25.3±3.8 years). Casual and ambulatorial blood pressure (BP), carotid-femoral pulse wave velocity (PWV) and biochemistry were analysed. BP, nor-epinephrine (NE), epinephrine (EPI), endothelin-1 (ET-1) and nitrite/nitrate (NOx) levels were also analysed during a graded exercise test (GXT). Casual and ambulatorial BP were not different between groups, but PWV was 7.5 and 12.6% higher in FH++ than FH+ and FH-, respectively, and 4.8% higher in FH+ than FH- (P≤0.01). Insulin and insulin-to-glucose ratio were increased in FH++ and FH+ (P<0.05), and low-density lipoprotein (LDL)-cholesterol tended to be higher only in FH++ (P=0.07). FH++ showed higher exercise and recovery diastolic BP and EPI levels, and increased resting, exercise and recovery NE, and ET-1 levels than FH- (P<0.05). FH+ showed only greater resting, exercise and recovery NE, and rest ET-1 (P<0.05). Resting, exercise and recovery NOx were lower in FH++ and FH+ than FH- (P<0.01). Haemodynamic, metabolic and hormonal abnormalities were presented in nonhypertensive young women offspring of hypertensive parents before any increase in BP. Greater abnormalities were observed in women with a strong family history of hypertension (FH++). These results suggest that there is an early vascular, metabolic and hormonal involvement in a familial hypertensive disorder.

Acute effects of a single dose of phosphodiesterase type 5 inhibitor (sildenafil) on systemic arterial blood pressure during exercise and 24-hour ambulatory blood pressure monitoring in heart transplant recipients.

BACKGROUND: Arterial systemic hypertension (SH) can be associated with a decrease in endothelium-dependent nitric oxide (NO). Sildenafil increases cyclic guanosine monophosphate (cGMP), a mediator of NO. However, little is known about the effects of PDE5 inhibition on 24-hour ambulatory pressure (ABP) and exercise blood pressure, noreprinephrine (Nor), and exercise capacity, especially after orthotopic heart transplantation (OHT). METHODS: We studied 22 OHT patients who on the 1st day underwent a cardiopulmonary (CP) self-controlled treadmill 6' walk test (6') and, then, an ECG monitored CP treadmill maximal exercise test (Ex) within 60 and 90 minutes after oral Sildenafil (Sil; 50 mg) or placebo (Pl) given at random, and ABP. We determined at basal position (b), in the last minute of the 6' and at the peak Ex, the HR (bpm), Systolic blood pressure (SBP), and diastolic blood pressure (DBP), (mm Hg), VO2 (mL/kg/min), Slope VE/VCO2, exercise time (ET, min), distance (D; miles), and Nor (pg/mL). Also, after CP tests, 24-h SBP and DBP, the measurements were repeated on the 2nd day when the cross-over was done. RESULTS: Sil significantly reduced blood pressure in the basal position and during exercise. It also promoted a significant reduction in SBP and DBP during 24 hours, daytime and nighttime. Sil did not change exercise capacity. CONCLUSION: The NO-cGMP pathway seems to play a role in blood pressure control in OHT. In addition to antihypertensive therapy, PDE5 inhibition may have potential beneficial effects on hypertensive OHT.

Cardiopulmonary exercise testing in children with heart failure secondary to idiopathic dilated cardiomyopathy.

STUDY OBJECTIVE: To determine and compare the cardiopulmonary responses of healthy children and children with heart failure due to idiopathic dilated cardiomyopathy (IC) to progressive treadmill exercise testing. SETTING: University teaching hospital specializing in cardiology. PATIENTS OR PARTICIPANTS: Twenty-six children with stable, chronic heart failure (left ventricular ejection fraction < 45%) caused by IC (IC group) and 12 healthy children (control group). INTERVENTIONS: After 12-lead resting ECG, all children underwent progressive treadmill exercise testing using a modified Naughton protocol. Tests were performed in a controlled-temperature exercise facility, at least 2 h after a light meal. MEASUREMENTS AND RESULTS: Cardiopulmonary parameters were assessed at rest, at anaerobic threshold (AT), and at peak exercise. At rest, the tidal volume (VT) and O(2) consumption (VO(2)) for heart rate (O(2) pulse) were lower, while the heart rate, respiratory rate, and ventilatory equivalent for O(2) (minute ventilation [VE]/VO(2)) were higher in the IC group compared with the control group. At AT, the systolic BP, O(2) pulse, VT, exercise duration, VO(2), CO(2) production (VCO(2)), and VE were lower, while the VE/VO(2) and ventilatory equivalent for CO(2) (E/CO(2)) were higher in the IC group (p < 0.05). At peak exercise, the IC group had a significantly lower systolic BP, O(2) pulse, VE, VT, exercise duration, VO(2), and VCO(2), but higher VE/VO(2) and VE/VCO(2) than the control group (p < 0.05). The VE/VCO(2) slope was significantly higher for the IC group. No correlation existed between variables evaluated at rest vs during exercise. CONCLUSIONS: Gas exchange analysis performed during exercise successfully differentiated children with heart failure from healthy children.

Exercise and heart failure. Relation of the severity of the disease to the anaerobic threshold and the respiratory compensation point.

OBJECTIVE - To identify, the anaerobic threshold and respiratory compensation point in patients with heart failure. METHODS - The study comprised 42 Men,divided according to the functional class (FC) as follows: group I (GI) - 15 patients in FC I; group II (GII) - 15 patients in FC II; and group III (GIII) - 12 patients in FC III. Patients underwent a treadmill cardiopulmonary exercise test, where the expired gases were analyzed. RESULTS - The values for the heart rate (in bpm) at the anaerobic threshold were the following: GI, 122+/-27; GII, 117+/-17; GIII, 114+/-22. At the respiratory compensation point, the heart rates (in bpm) were as follows: GI, 145+/-33; GII, 133+/-14; GIII 123+/-22. The values for the heart rates at the respiratory compensation point in GI and GIII showed statistical difference. The values of oxygen consumption (VO2) at the anaerobic threshold were the following (in ml/kg/min): GI, 13. 6+/-3.25; GII, 10.77+/-1.89; GIII, 8.7+/-1.44 and, at the respiratory compensation point, they were as follows: GI, 19.1+/-2. 2; GII, 14.22+/-2.63; GIII, 10.27+/-1.85. CONCLUSION - Patients with stable functional class I, II, and III heart failure reached the anaerobic threshold and the respiratory compensation point at different levels of oxygen consumption and heart rate. The role played by these thresholds in physical activity for this group of patients needs to be better clarified.

Nitric oxide inhalation reduces pulmonary tidal volume during exercise in severe chronic heart failure.

Multiple mechanisms have been proposed to explain the hyperventilation and the limited exercise capacity in congestive heart failure (CHF) including increased intrapulmonary pressures, total pulmonary resistance, and airway abnormalities. We investigated the hypothesis that inhalation of nitric oxide could influence the maximum exercise capacity and excessive ventilatory response to exercise in CHF. Fifteen patients in CHF (mean age 48 +/- 12 years) underwent a control and a nitric oxide inhalation progressive treadmill exercise test with 30 ppm. We determined the maximum oxygen consumptiom (peak VO2), CO2 production (VCO2), minute pulmonary ventilation (VE), respiratory rate, tidal volume (VT), ventilatory equivalent for oxygen (VE/VO2), ventilatory equivalent for carbon dioxide (VE/VCO2), estimated physiologic dead space/tidal volume ratio (VD/VT), VE/VCO2 slope, heart rate, systemic arterial pressure, VE/exercise time slope, and VT/exercise time slope during every incremental exercise. Mean maximum exercise values of heart rate, systolic systemic arterial pressure, diastolic systemic arterial pressure, VD/VT, respiratory rate, peak VO2, VO2/heart rate, VE/CO2, and maximum exercise time were unchanged by inhalation of nitric oxide. There was a strong trend toward reduction of VE/VO2 from 53 +/- 15 to 47 +/- 12 (p = 0.051) and in maximum VE from 58 +/- 21 to 48 +/- 17 L x min(-1) (p = 0.059). Maximum VT decreased from 1639 +/- 556 to 1406 +/- 479 ml (p = 0.04). The VE/VCO2 slope was reduced from 43 +/- 12 to 35 +/- 8 (p = 0.018). Two patients had signs of pulmonary congestion during peak exercise or the recovery period with inhalation of nitric oxide. The VE/exercise time slope and VT/exercise time slope during incremental exercise were reduced by inhalation of nitric oxide, demonstrating a statistically significant minor increase in VE and VT. Inhalation of nitric oxide attenuated the excessive increase in VT response to exercise in CHF. The L-arginine-nitric oxide pathway may be involved in mechanisms contributing to hyperventilation during exercise in CHF.

Capacidade física em idosos submetidos a programa de condicionamento físico / Physical capacity in elderly subjects engaged in an exercise training program

No presente trabalho, säo relatados resultados obtidos a partir de avaliaçäo ergométrica e cardiorrespiratória ao exercício (ergoespirométrica), em idosos, sadios ou portadores de doença cardiovascular, incluídos em programa de condicionamento físico em nosso Serviço. Nossa experiência tem confirmado que um programa de atividade física regular supervisionada, mesmo quando iniciado em idade avançada, pode trazer benefícios para indivíduos sadios ou näo, independentemente do sexo. A adoçäo de hábitose vida ativa atenua a reduçäo da capacidade física associada a idade ou doençae, portanto, pode melhorar a qualidade de vida nessa populaçäo. A heterogeneidade de comportamento do idoso implica a necessidade de individualizaçäo de condutas. Assim, a avaliaçäo da capacidade física ao início e no decorrer do treinamento físico tem-se mostrado essencial para adequaçäo da prescriçäo da intensidade de exercício. Ademais, individualizaçäo do tratamento parece ser ponto importante para a permanência nos prograade reabilitaçäo. A prescriçäo de treinamento físico baseada na resposta cronotrópica, ou seja, na reserva de frequência cardíaca ou na frequência cardíaca máxima, exibe limitaçöes, podendo superestimar a capacidade funcional de indivíduos jovens e idosos. A popularizaçäo de avaliaçäo cardiorrespiratória ao exercício pode proporcionar a realizaçäo rotineira de prescriçäo de treinamento físico baseada näo apenas na frequência cardíaca, mas principalmente no estresse metabólico causado pelo exercício, torano os programas mais preciosos e adequados. Apesar dos benefícios aqui demostrados, em diversas condiçöes, altos índices de desistência e obsenteísmo enfatizam a importância de conscientizar o idoso e o profissional de saúde quanto à necessidade de adoçäo e/ou manutençäo de um estilo de vida ativo.