Hirotaka Nishijima

Determination of anaerobic threshold for assessment of functional state in patients with chronic heart failure.

The use of anaerobic threshold in assessment of aerobic capacity was evaluated in 34 normal subjects and 47 patients with various kinds of chronic heart disease. Anaerobic threshold was determined as the oxygen consumption (VO2) at which a linear relationship between pulmonary ventilation (VE) and VO2 was lost during progressive treadmill exercise. Anaerobic threshold determined in this manner was validated with that determined by blood lactate measurements in eight normal subjects and nine cardiac patients (r = .962, p less than .001). Thereafter, anaerobic threshold was determined only by respiratory measurements. In symptom-limited, maximal exercise, anaerobic threshold was reached well before maximal effort and corresponded to 70% of maximal VO2 both in normal subjects and cardiac patients. Anaerobic threshold decreased as age progressed in normal subjects (r = - .70, p less than .001). Anaerobic threshold in cardiac patients was lower than that in the normal subjects and decreased progressively as New York Heart Association functional classification advanced (normal, 32.95 +/- 6.17 ml/min/kg; class I, 22.78 +/- 3.74; class II, 16.99 +/- 3.66; class III, 12.97 +/- 2.76; p less than .01 between each group other than between class II and class III). Anaerobic threshold in cardiac patients correlated poorly with other objective indices, e.g., cardiomegaly (r = -.54, p less than .001) and rise in pulmonary wedge pressure (r = -.64, p less than .001). At anaerobic threshold, cardiac patients subjectively graded the work load as light (13%), light-to-moderate (27%), moderate (30%), and moderate-to-heavy (28%). Thus determination of anaerobic threshold by respiratory measurements is a safe, accurate, and objective method to measure aerobic capacity in cardiac patients and in normal subjects.

Can Exercise Training With Weight Loss Lower Serum C-Reactive Protein Levels?

Objective—C-reactive protein (CRP), an obesity-related inflammatory marker, is a promising predictor for cardiovascular disease and may be a mediator for atherogenesis. It has been reported that diet-induced weight loss lowered CRP levels. However, the effect of exercise training, another therapy that can reduce weight, on CRP is still unclear. We examined effects of exercise training with weight loss on CRP levels and conventional cardiovascular risks. Methods and Results—A total of 227 apparently healthy women were recruited, and 199 subjects (average age 52 years) completed a 2-month weight reduction program consisting of supervised aerobic exercises. After the program, weight was reduced from 65.8 to 62.8 kg (P<0.0001), and all conventional variables were remarkably improved. Similarly, CRP levels were significantly decreased, from 0.63 (0.28 to 1.19) to 0.41 (0.18 to 0.80) mg/L (P<0.0001). However, in contrast to other variables, the changes in CRP levels were not proportionally associated with the extent of weight reduction. In the quartile analysis of % weight reduction, the largest weight reduction quartile did not show significant decreases in CRP levels, whereas moderate quartile showed remarkable CRP decreases. Conclusions—Exercise training with weight reduction disproportionately lowered CRP levels. Considering inflammatory status, there might be an optimal pace of exercise with weight loss.

Skeletal Muscle Metabolism Limits Exercise Capacity in Patients With Chronic Heart Failure

BACKGROUND Several studies have indicated that skeletal muscle is important in determining the exercise capacity of patients with chronic heart failure (CHF). However, this theory has been investigated only in experiments based on local exercise involving a small muscle mass. We investigated skeletal muscle metabolism during maximal systemic exercise to determine whether muscle metabolism limits exercise capacity in patients with CHF. We also studied the relationship between muscle metabolic abnormalities during local and systemic exercise. METHODS AND RESULTS Skeletal muscle metabolism was measured during maximal systemic exercise on a bicycle ergometer by a combination of the metabolic freeze method and 31P magnetic resonance spectroscopy in 12 patients with CHF and 7 age- and size-matched normal subjects. We also evaluated skeletal muscle metabolism during local exercise while subjects performed unilateral plantar flexion. Muscle phosphocreatine (PCr) was nearly depleted during maximal systemic exercise in patients with CHF and normal subjects (12.5+/-0.04% and 12.3+/-0.07%, respectively, of initial level). PCr depletion occurred at a significantly lower peak oxygen uptake (peak VO2) in patients with CHF than in normal subjects (CHF, 20.2+/-3.0 versus normal, 31.8+/-3.7 mL . min-1 . kg-1, P<0. 0001). Muscle metabolic capacity, evaluated as the slope of PCr decrease in relation to increasing workload, was correlated with peak VO2 during maximal systemic exercise in patients with CHF (r=0.83, P<0.001). Muscle metabolic capacity during local exercise was impaired in patients with CHF and was correlated with capacity during systemic exercise (r=0.76, P<0.01) and with peak VO2 (r=0. 83, P<0.001). CONCLUSIONS These results suggest that impaired muscle metabolism associated with early metabolic limitation determines exercise capacity during maximal systemic exercise in patients with CHF. There was a significant correlation between muscle metabolic capacity during systemic and local exercise in patients with CHF.

Plasma norepinephrine concentration and plasma dopamine-beta-hydroxylase activity in patients with congestive heart failure.

The relationship between plasma norepinephrine (NE), epinephrine (E) and dopamine-betahydroxylase activity (DBH) was studied in 90 cardiac patients (New York Heart Association [NYHA] classes I-IV), 85 healthy control subjects and 18 competitive skiers. The cardiac patients in NYHA classes III and IV had significantly higher NE (p < 0.001) and lower DBH (p < 0.001) levels than the controls, whereas the skiers had significantly lower NE (p < 0.001) and higher DBH (p < 0.05) levels than the controls. Seven cardiac patients in whom successful cardiac surgery was performed had decreased NE (p < 0.001) and increased DBH (p < 0.02), as well as significantly improved NYHA cardiac status (p < 0.001). These findings demonstrate an inverse relationship between NE and DBH in a population of athletes, normal subjects and cardiac patients; the same inverse relationship holds for these patients when sequential studies are done after a change in cardiac status.

Metabolic abnormality of calf skeletal muscle is improved by localised muscle training without changes in blood flow in chronic heart failure

Objective To investigate whether localised skeletal muscle training, which does not have a great influence on the heart, improves abnormalities of calf muscle metabolism in patients with chronic heart failure. Methods Seven cardiac patients in New York Heart Association class II and III undertook a random order crossover trial. Training consisted of unilateral calf plantar flexion exercise. Before and after training, the patients’ metabolic responses were examined during the calf exercise test with phosphorus-31 nuclear magnetic resonance spectroscopy (31P-MRS) and calf blood flow with plethysmography. The new Borg scale was employed as a subjective fatigue scale. Results In a constant load exercise test (70% of maximum load achieved during the incremental exercise), standardised phosphocreatine and intracellular pH decreased less after training (p < 0.05, repeated measures analysis of variance). The new Borg scale improved significantly after training (p < 0.05). Blood flow did not change significantly in either test. Conclusions In patients with chronic heart failure, localised calf skeletal muscle training improved oxidative capacity without changes in calf blood flow. This training also improved the subjective fatigue scale. This training method may therefore alleviate leg fatigue experienced in daily activities.

Skeletal Muscle Metabolism in Maximal Bicycle and Treadmill Exercise Distinguished by Using In Vivo Metabolic Freeze Method and Phosphorus-31 Magnetic Resonance Spectroscopy in Normal Men

This study indicates that skeletal muscle metabolism may affect the results of maximal bicycle and treadmill exercise differently, and that maximal bicycle exercise was limited by quadriceps muscle metabolism rather than by cardiopulmonary capacity. In contrast, maximal treadmill exercise was not limited, eliciting more cardiopulmonary reserve and attaining greater peak oxygen uptake than maximal bicycle exercise.

Phosphorus-31 magnetic resonance spectroscopy of forearm flexor muscles in student rowers using an exercise protocol adjusted for differences in cross-sectional muscle area

SummaryTo assess exercise energy metabolism of forearm flexor muscles in rowers, six male student rowers and six control subjects matched for age and sex were studied using phosphorus-31 magnetic resonance spectroscopy (31P-MRS). Firstly, to adjust for the effect of differences in cross-sectional muscle area, the maximal cross-sectional area (CSAmax) of the forearm flexor muscles was estimated in each individual using magnetic resonance imaging. Multistage exercise was then carried out with an initial energy production of 1 J · cm−2 CSAmax for 1 min and an increment of 1 J · cm−2 CSAmax every minute to the point of muscle exhaustion. A series of measurements of31P-MRS were performed every minute. The CSAmax was significantly greater in the student rowers than in the control subjects [19.8 (SD 2.2) vs 17.1 (SD 1.2) cm2,P<0.05]. The absolute maximal exercise intensity (J · min−1) was greater in the rowers than in the control subjects. However, the maximal exercise intensity per unit of muscle cross sectional area (J · min−1 · cm−2) was not significantly different between the two groups. During mild to moderate exercise intensities, a decrease in phosphocreatine and an increase in inorganic phosphate before the onset of acidosis were significantly less in the rowers, indicating a requirement of less adenosine 5′-diphosphate to drive adenosine 5′-triphosphate production. The onset of acidosis was also significantly delayed in the rowers. No difference was observed in forearm blood flow between the two groups at the same exercise intensity (J · min−1 · cm−2). These results demonstrated that the findings of the maintenance of a higher level of phosphocreatine and a lower level of inorganic phosphate with less acidosis observed in the rowers were the results of the intrinsic characteristics of energy metabolism of their muscles and that these characteristics were independent of their greater cross-sectional muscle area.

Muscle high-energy metabolites and metabolic capacity in patients with heart failure.

UNLABELLED OKITA, K., K. YONEZAWA, H. NISHIJIMA, A. HANADA, T. NAGAI, T. MURAKAMI, and A. KITABATAKE. Muscle high-energy metabolites and metabolic capacity in patients with heart failure. Med Sci. Sports. Exerc., Vol. 33, No. 3, 2001, pp. 442-448. BACKGROUND Various abnormalities in skeletal muscle have been demonstrated by biopsy in patients with chronic heart failure (CHF). In mammalian muscles, high-energy metabolite composition at rest (HEMC) provides data on important metabolic characteristics; however, the significance of HEMC has not been clarified in patients with CHF. Therefore, we investigated HEMC in normal subjects and patients with CHF and examined its relation to muscle metabolic capacity and exercise tolerance. METHODS High-energy metabolites (phosphocreatine (PCr), inorganic phosphate (Pi), and ATP) in resting calf muscle were measured by 31P-magnetic resonance spectroscopy (31P-MRS), and ratios of Pi to PCr, Pi to ATP, and PCr to ATP were calculated in 34 patients with CHF and 13 age- and size-matched normal subjects. Muscle metabolism was evaluated during local exercise of unilateral plantar flexion by 31P-MRS. Metabolic capacity was estimated by the rate of PCr breakdown in relation to the workload. Systemic exercise capacity was evaluated by a bicycle ergometer. RESULTS The ratio of PCr to ATP was significantly increased in patients with CHF compared with controls (3.06 +/- 0.43 vs 2.72 +/- 0.36, P < 0.05) and was significantly correlated with metabolic capacity (r = -0.37, P < 0.01) and with peak oxygen uptake (r = -0.45, P < 0.01). There was a significant correlation between metabolic capacity and peak oxygen uptake (r = 0.53, P < 0.001). CONCLUSION HEMC was altered in patients with CHF, and this change was related to metabolic capacity and exercise capacity. These findings provide new insight into the mechanism of impaired muscle metabolism in CHF.

Relationship between lipids and angiographically defined coronary artery disease in Japanese patients

The relationship between the severity and extent of coronary artery disease (CAD) and the lipid profiles was evaluated in 120 Japanese male patients, who underwent coronary angiography. Analysis of the lipid quartile distribution showed that the percentage of patients with significant CAD increased as the total cholesterol (TC) increased and high-density lipoprotein cholesterol (HDL-C) decreased. In addition, as the number of vessels with marked coronary artery stenosis increased, TC and TC/HDL-C increased while HDL-C decreased. However, within this population, triglyceride level, high blood pressure, and smoking were not significantly associated with coronary angiographic findings.

Sapporo Fitness Club Trial (SFCT)

Background The annual health check followed by lifestyle recommendations has long been the standard national strategy to improve cardiovascular disease (CVD) risk factors in Japan. Exercise at fitness clubs, now widely accessible in major cities, has a novel appeal as a strategy with the additive effect of CVD risk reduction. The Sapporo Fitness Club Trial (SFCT) is a randomized controlled trial to compare the efficacy of the national standard alone (control) with the standard plus exercise at a fitness club (intervention) for the reduction of CVD risk factors. Methods The SFCT has recruited and randomized 561 relatively inactive overweight men and women, aged 40-85 years, with elevated levels of 2 or more of the following: systolic blood pressure, fasting blood glucose, and low-density lipoprotein cholesterol. The intervention group was required to exercise at a fitness club 2-4 times per week. At the end of 6 months, risk factors, aerobic capacity, health-related quality of life measures, and adverse effects are to be compared. Conclusion The SFCT is expected to have a major impact in Japan on public health recommendations on exercise for the reduction of lifestyle-related disease. (Circ J 2004; 68: 1199 - 1204)