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Maximum gait speed and physical activity (PA) relate to mortality and morbidity, but little is known about gender-related differences in these factors in elderly hospitalized cardiac inpatients. This study aimed to determine differences in maximum gait speed and daily measured PA based on sex and the relationship between these measures in elderly cardiac inpatients.A consecutive 268 elderly Japanese cardiac inpatients (mean age, 73.3 years) were enrolled and divided by sex into female (n = 75, 28%) and male (n = 193, 72%) groups. Patient characteristics and maximum gait speed, average step count, and PA energy expenditure (PAEE) in kilocalorie per day for 2 days assessed by accelerometer were compared between groups.Gait speed correlated positively with in-hospital PA measured by average daily step count (r = 0.46, P < 0.001) and average daily PAEE (r = 0.47, P < 0.001) in all patients. After adjustment for left ventricular ejection fraction, step counts and PAEE were significantly lower in females than males (2651.35 ± 1889.92 vs 4037.33 ± 1866.81 steps, P < 0.001; 52.74 ± 51.98 vs 99.33 ± 51.40 kcal, P < 0.001), respectively.Maximum gait speed was slower and PA lower in elderly female versus male inpatients. Minimum gait speed and step count values in this study might be minimum target values for elderly male and female Japanese cardiac inpatients.

The aim of this study was to clarify the mechanism of impaired exercise tolerance in chronic sleep-restricted conditions by investigating variables related to heart-rate (HR) response to sympathetic nervous stimulation. Sixteen healthy men (mean age 21.5 years) were tested in a control state, acute sleep-loss state, and chronic sleep-restricted state. Participants underwent cardiopulmonary exercise testing in each state. Their norepinephrine (NE) concentration was measured before and immediately after exercise. Intracellular magnesium (Mg) concentration was measured in a resting state. Exercise duration was shorter and the ratio of HR response to the percentage increase in NE was higher in the chronic sleep-restricted state than in the control state. Intracellular Mg gradually decreased from control to chronic sleep restriction. There was a negative correlation between peak exercise duration and the ratios of HR response to the rate of increase in NE. Intracellular Mg was positively correlated with the ratios of HR response to the increase in NE both in control and in acute sleep loss. The authors conclude that the impaired exercise tolerance in a chronic sleep-restricted state is caused by hypersensitivity of the HR response to sympathetic nervous stimulation, which showed a compensation for decreased intracellular Mg concentration.

Background: No previous studies have fully investigated the exercise training effect on the skeletal muscle strength and volume to improve the exercise capacity in patients with myocardial infarction (MI). The present study was performed based on a hypothesis that the relationship between exercise capacity, skeletal muscle strength and volume might be changed by the amount of skeletal muscle volume in MI patients up to 3 months after the onset., Methods: Seventy patients with MI underwent symptom-limited cardiopulmonary exercise testing using a treadmill. The lower limb muscle volume (MV) was evaluated according to electrical impedance analysis and the maximal knee extension strength (Peak torque: PT) was measured by a Biodex. All patients participated in 12-week exercise training program. The subjects were divided into 2 groups on the basis of MV: Group H, MV>==22 kg; Group L, MV<22 kg. Delta values were calculated as follows: the value at 3 months minus the value at 1 month., Results: A positive and significant correlation was observed between the delta PT and delta peak VO(2) (r=0.50, p<0.005) only in the L group. No significant correlation was observed between the delta peak VO(2) and the delta lower limb MV or between the delta lower limb MV and the delta PT in the 2 groups., Conclusions: Cardiac rehabilitation program combined with resistance and aerobic training improved exercise capacity and increased not the skeletal muscle volume but the skeletal muscle strength in patients with MI in their recovery phase. It was presumed that the improvement of exercise capacity was determined by the skeletal muscle strength not by the muscle volume especially in MI patients with low muscle volume.

Objective: To evaluate the effect of the self-monitoring approach (SMA) on self-efficacy for physical activity (SEPA), exercise maintenance, and objective physical activity level over a 6-mo period after a supervised 6-mo cardiac rehabilitation (CR) program., Design: We conducted a randomized, controlled trial with 45 myocardial infarction patients (38 men, seven women; mean age, 64.2 yrs) recruited after completion of an acute-phase, exercise-based CR program. Patients were randomly assigned to an SMA group (n = 24) or control group (n = 21). Along with CR, the subjects in the SMA group self-monitored their weight and physical activity for 6 mos. The SMA used in this study was based on Bandura's self-efficacy theory and was designed to enhance confidence for exercise maintenance. The control group participated in CR only. All patients were evaluated with the SEPA assessment tool. Exercise maintenance, SEPA scores, and objective physical activity (average steps per week) as a caloric expenditure were assessed at baseline and during a 6-mo period after the supervised CR program., Results: Mean period from myocardial infarction onset did not differ significantly between the SMA and control groups (12.1 +/- 1.3 vs. 12.2 +/- 1.2 mos, P = 0.692). All patients maintained their exercise routine in the SMA group. Mean SEPA score (90.5 vs. 72.7 points, P < 0.001) and mean objective physical activity (10,458.7 vs. 6922.5 steps/wk, P < 0.001) at 12 mos after myocardial infarction onset were significantly higher in the SMA than control group. SEPA showed significant positive correlation with objective physical activity (r = 0.642, P < 0.001)., Conclusions: SMA during supervised CR may effectively increase exercise maintenance, SEPA, and objective physical activity at 12 mos after myocardial infarction onset.

Objective: The purpose of this study was to determine exercise maintenance rate, leisure-time objective physical activity level, and health-related quality of life in relation to exercise maintenance over the 6-mo period after a supervised 5-mo recovery-phase cardiac rehabilitation program in acute myocardial infarction patients. The study also investigated whether exercise maintenance resulted in reproducible health-related quality-of-life outcomes comparable with those of the Japanese normal population., Design: This observational study comprised 109 acute myocardial infarction patients (89 men, 20 women; mean age, 63.5 +/- 10.1 yrs). Physiologic outcomes (peak oxygen uptake, handgrip, and knee-extension strength) measured at 1 and 6 mos after acute myocardial infarction onset were compared. Completed exercise maintenance and health-related quality-of-life questionnaires and results of electronic pedometer recordings to evaluate leisure-time objective physical activity level were assessed 6 mos after cardiac rehabilitation., Results: The mean period from acute myocardial infarction to evaluation of outcomes was 18.8 +/- 3.4 mos. Ninety of 109 patients (82.6%) continued exercise for >6 mos after cardiac rehabilitation (exercise group); 19 patients (17.4%) quit exercise after cardiac rehabilitation (nonexercise group). Improvement in physiologic outcomes was noted at 6 mos vs. those at 1 mo, but outcomes were not significantly different between groups. The exercise group performed significantly better than the nonexercise group for leisure-time objective physical activity level and scored significantly higher than the nonexercise group for seven of eight health-related quality of life measures, attaining scores similar to those of the Japanese normal population., Conclusions: At >18 mos after acute myocardial infarction, the exercise maintenance rate in our patients remains high, and exercise maintenance may be one of the factors contributing to improvement of health-related quality of life and leisure-time objective physical activity level.

There have been no previous studies that clearly demonstrate the effects of training on the relation between exercise capacity and vasodilatory capacity in skeletal muscle. This study was performed to clarify the effects of short-term, moderate-intensity physical training on exercise tolerance and vasodilatory capacity in cardiac patients. We studied 21 patients after acute myocardial infarction, coronary artery bypass grafting, or valve replacement. Each patient performed symptom-limited incremental exercise tests before and after a 2-week training program of moderate-intensity exercise. A cycle ergometer was used for both the training and exercise tests. Blood pressure measurement and respiratory gas analysis were continuously performed during the tests. Cardiac output was also measured using a dye-dilution method at rest and every 2 minutes during incremental exercise. Reactive hyperemic calf blood flow was measured at rest. After the training program, the subjects attained a significant decrease in systemic vessel resistance and significant increases in oxygen uptake and cardiac output at peak exercise. Changes in reactive hyperemic calf blood flow were significantly correlated with the changes in cardiac output, systemic vascular resistance, and the kinetics of oxygen uptake during warm-up exercise. By improving the peripheral vasodilatory capacity in these patients, short-term, moderate-intensity physical training was found to improve the cardiovascular adaptation not only at peak exercise, but also during the onset of exercise.

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide produced by vascular endothelial cells. However, the role of ET-1 in exercise-induced physiological responses is still to be investigated. The purpose of the present study was to investigate in healthy volunteers whether the ET-1 plasma concentration in nonworking muscles is changed by exercise and to investigate the physiological role of ET-1 during exercise. Bicycle ergometer cardiopulmonary exercise tests were performed in 36 healthy men (mean age, 22.5 years). Blood samples for measuring ET-1 were drawn from the cubital vein during rest and immediately after the exercise test. The ET-1 change ratio was calculated as ET-1 immediately following exercise/ET-1 during the resting state. Cardiac output (CO) was measured during the exercise test by the impedance method. Arterial venous oxygen difference (AVO2D) when CO reached 10L/min or 15L/min was calculated as AVO2D = VO2/CO. Results were as follows: (1) the ET-1 change ratio correlated inversely with exercise time at the anaerobic threshold (r = -0.37, p = 0.03) and peak exercise time (r = -0.35, p = 0.04); (2) the ET-1 change ratio tended toward an inverse correlation with deltaVO2/deltawork rate (r = -0.29, p = 0.09); (3) the ET-1 change ratio correlated positively with AVO2D when CO reached 10L/min (r = 0.42, p = 0.02) and tended toward a positive correlation with AVO2D when CO reached 15 L/min (r = 0.32, p = 0.08). These results indicate that an increase in ET-1 in nonworking muscles may participate in the exercise-induced redistribution of blood flow and in increasing the blood flow to working muscles.

Exercise training usually involves the sustained performance of exercise at a prescribed intensity. The effects of exercise performed at the anaerobic threshold (AT) have been widely studied. The effects of single-level exercise on catecholamines and cardiac function were assessed at the AT, and at 120% of the AT in eight healthy Japanese men (mean age 21.9 +/- 1.8 years). 1) Symptom-limited exercise testing utilized the ramp protocol with a bicycle ergometer (20 watts/min) for measuring AT and peak oxygen uptake (peak VO2). 2) Exercise testing was repeated on another day, following the same protocol, with blood sampled to measure norepinephrine (NE) and epinephrine (E) in the resting control state and at the AT and peak exercise. 3) Single-level exercise testing at the AT and at 120% of AT utilized the bicycle ergometer on yet another day. Blood for measurement of NE and E was drawn at 3 and 7 min after achieving a steady-state condition. In addition, the cardiac index (CI) and stroke index (SI) were measured by the CO2 rebreathing method. (1) Mean AT and peak VO2 were 18.3 +/- 1.3 and 40.2 +/- 3.0 ml/min/g, respectively. (2) NE and E measured during ramp exercise testing increased rapidly when the intensity of exercise exceeded the AT. NE measured after 3 and 7 min at the AT during single-level exercise equalled 94.7% and 94.5% of the NE value measured at the AT of ramp exercise, respectively. NE measured after 3 and 7 min at 120% of the AT during single-level exercise was 124.7% and 144.7% at the AT of ramp exercise, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)