负荷运动对能量代谢的影响及研究

目的探讨渐增负荷最大运动后的过量氧耗与血乳酸、血糖及氨基酸代谢的变化关系。方法受试者为10名男子健康大学生。采用活动跑台方法进行渐增负荷跑至力竭为止。结果运动结束30min,吸氧量恢复到安静水平时,血乳酸浓度仍比安静时水平高,运动中丙氨酸上升,运动结束30min丙氨酸减少,但并未恢复到安静时的水平。结论过量氧耗除用于血乳酸的消耗外,可能生要用于丙氨酸代谢中的糖新生。     

Assessment of exercise capacity in women with type 2 diabetes

The primary aim of this study was to compare the maximal oxygen uptake as evaluated from a submaximal exercise test (EVO2peak) to direct measurements of VO2peak during a maximal exercise test as means of monitoring the aerobic endurance capacity in women with type 2 diabetes (T2D). Twenty-seven women with T2D participated in the study. The program consisted of combined group training 1 h twice a week during 12 weeks and walks 1 h per week. EVO2 max was estimated using a submaximal exercise test on a bicycle ergometer ad modum Astrand. VO2peak and maximal work rate were measured using an incremental maximal exercise test on an electrically braked bicycle ergometer at baseline and after 6 and 12 weeks. EVO2peak was higher than VO2peak at baseline and significantly higher at 12 weeks (EVO2peak1.92+/-0.54 l min(-1), VO2peak 1.41+/-0.36, P<0.005). Maximal work rate increased significantly after 12 weeks (12+/-15, P<0.005) compared to baseline. The main finding of this study was that EVO2peak assessed using a submaximal exercise test, systematically overestimated VO2peak. The combined group training increased maximal work rate but not VO2peak. This is likely to reflect peripheral adaptation to exercise and/or improved mechanical efficiency.     

Blood metabolite data in response to maximal exercise in healthy subjects

Maximal exercise test with gas exchange measurement evaluates exercise capacities with maximal oxygen uptake (VO(2) max) measurement. Measurements of lactate (L), lactate/pyruvate ratio (L/P) and ammonium (A) during rest, exercise and recovery enhance interpretative power of maximal exercise by incorporating muscular metabolism exploration. Maximal exercise test with gas exchange measurement is standardized in cardiopulmonary evaluations but, no reference data of blood muscular metabolites are available to evaluate the muscular metabolism. We determined normal values of L, L/P and A during a standardized maximal exercise and recovery in 48 healthy sedentary volunteers and compared with results obtained in four patients with exercise intolerance and a mitochondrial disease. In healthy subjects, L, L/P and A rose during exercise. In 98% of them L, L/P or A decreased between the fifth and the fifteenth minutes of recovery. In mitochondrial patients, VO(2) max was normal or low, and L, L/P and A had the same evolution as normal subjects or showed no decrease during recovery. We gave normal L, L/P and A values, which establish references for a maximal exercise test with muscular metabolism exploration. This test is helpful for clinicians in functional evaluation, management and treatment of metabolic myopathy and would be a useful tool in diagnosis of metabolic myopathy.     

Reference values for cardiopulmonary exercise testing in healthy adults: a systematic review

Reference values (RV) for cardiopulmonary exercise testing (CPET) provide the comparative basis for answering important questions concerning the normality of exercise response in patients and significantly impacts the clinical decision-making process. The aim of this study is to systematically review the literature on RV for CPET in healthy adults. A secondary aim is to make appropriate recommendations for the practical use of RV for CPET. Systematic searches of MEDLINE, EMBASE and PEDro databases up to March 2014 were performed. In the last 30 years, 35 studies with CPET RV were published. There is no single set of ideal RV; characteristics of each population are too diverse to pool the data in a single equation. Therefore, each exercise laboratory must select appropriate sets of RV that best reflect the characteristics of the population/patient tested, and equipment and methodology utilized.     

麻醉犬等长收缩运动中血浆一氧化氮浓度变化及其对血流动力学的影响

目的通过麻醉犬等长收缩运动(IE)中一氧化氮(NO)变化及与注入一氧化氮合成酶(NOS)抑制剂前后IE时心血管指标变化的比较,探讨NO对IE时血流动力学变化的调节作用.方法成年健康杂种犬14只,在安静、IE 3、6、9min,恢复5、10、20min时测定NO及各项血液动力学指标;然后注入NOS抑制剂,重复原试验,测各时间点血流动力学指标.结果IE时NO浓度下降,IE 9min时下降23.6% (P＜0.05),恢复期NO浓度水平逐渐恢复.IE 9min时心率上升明显(P＜0.05)而注入NOS抑制剂后IE 9min时HR下降明显(P＜0.05).收缩压、舒张压及肺毛细血管楔嵌压在注入NOS抑制剂后三者的净增量均高于注入前(P＜0.05).在注入NOS抑制剂后总肺循环阻力、肺动脉阻力、体循环血管阻力均明显上升(P＜0.05).结论急性运动时NO浓度水平下降;NO 不但可以降低外周血管阻力也可降低肺血管阻力,从而减轻IE时的心血管负荷.     

Effects of dopamine and dobutamine on the distribution of pulmonary blood flow during lobar ventilation hypoxia and lobar collapse in dogs

Hypoxic pulmonary vasoconstriction was induced in the left lower lobe of fifteen dogs by ventilating the lobe with 7% O2 or by absorption collapse, and the distribution of flow between the lobe and the remainder of the lung was measured with electromagnetic flow probes. The lobar to total blood flow ratio was reduced by lobar ventilation hypoxia and decreased further during lobar collapse. In seven dogs, an infusion of 20 micrograms kg-1 min-1 of dopamine produced an increase in total blood flow, an increase in pulmonary artery pressure (P less than 0.01), and an increase in lobar to total flow ratio (P less than 0.05) during both hypoxic states. There was a significant fall in arterial PO2 (P less than 0.01) during ventilation hypoxia. Similar changes in total and lobar to total flow ratio (P less than 0.01) were observed in eight dogs given 20 micrograms kg-1 min-1 of dobutamine, but there were no changes in pulmonary artery pressure. The greater increase in total flow (+ 111%) resulted in a marked increase in mixed venous PO2 and no significant changes in arterial PO2 in this group of dogs. It is concluded that both drugs produce an increase in lobar to total blood flow ratio and shunt fraction, but that the mechanisms causing the redistribution of flow may differ.     

Effect of exercise intensity on oxygen consumption kinetics in non-exercising muscle during exercise

This study examined the effect of exercise intensity on the kinetics of muscle oxygen consumption in non-exercising forearm flexor muscles (VO(2mf)) during exercise. Seven healthy male subjects performed cycling exercise for 60 min at 30% of maximal oxygen consumption (%VO(2max)) and 30 min at 50% VO(2max) on separate days. The VO(2mf) values at rest and during exercise were measured by near-infrared spectroscopy. The VO(2mf) at 30% VO(2max) significantly increased to 1·2 ± 0·1-fold over resting value at 20 min after the beginning of exercise (P<0·05) and remained constant within 1·2- to 1·3-fold over resting value until 60 min during exercise. The VO(2mf) at 50% VO(2max) significantly increased to 1·2 ± 0·1-fold over resting value at 15 min after the beginning of exercise (P<0·05). Subsequently, the VO(2mf) at 50% VO(2max) increased with time to 1·3 ± 0·1-fold over resting value at 20 min after the beginning of exercise and to 1·5 ± 0·2-fold over resting value at 30 min. The VO(2mf) 15-30 min of exercise at 50% VO(2max) was significantly higher than that at 30% VO(2max) (P<0·05). These data suggest that the increase in VO(2mf) has a time lag from the beginning of exercise, and the kinetics of VO(2mf) during exercise differs with exercise intensity. Therefore, we conclude that the kinetics of VO(2mf) during exercise is dependent on exercise intensity.     

The influence of a fast ramp rate on peak cardiopulmonary parameters during arm crank ergometry

The influence of a very fast ramp rate on cardiopulmonary variables at ventilatory threshold and peak exercise during a maximal arm crank exercise test has not been extensively studied. Considering that short arm crank tests could be sufficient to achieve maximal oxygen consumption (VO₂), it would be of practical interest to explore this possibility. Thus, this study aimed to analyse the influence of a fast ramp rate (20 W min^?1) on the cardiopulmonary responses of healthy individuals during a maximal arm crank ergometry test. Seventeen healthy individuals performed maximal cardiopulmonary exercise tests (Ultima CardiO2; Medical Graphics Corporation, St Louis, USA) in arm ergometer (Angio, LODE, Groningen, The Netherlands) following two protocols in random order: fast protocol (increment: 2 w/6 s) and slow protocol (increment: 1 w/6 s). The fast protocol was repeated 60–90 days after the 1st test to evaluate protocol reproducibility. Both protocols elicited the same peak VO₂ (fast: 23·51 ± 6·00 versus slow: 23·28 ± 7·77 ml kg^?1 min^?1; P = 0·12) but peak power load in the fast ramp protocol was higher than the one in the slow ramp protocol (119 ± 43 versus. 102 ± 39 W, P < 0·001). There was no other difference in ventilatory threshold and peak exercise variables when 1st and 2nd fast protocols were compared. Fast protocol seems to be useful when healthy young individuals perform arm cardiopulmonary exercise test. The usefulness of this protocol in other populations remains to be evaluated.     

Exaggerated blood pressure response to exercise: importance of resting blood pressure

Normotensive individuals who exhibit an exaggerated blood pressure (BP) response to exercise have an increased risk of future hypertension. However, previous studies failed to control for resting BP despite the fact that an elevated resting BP in the normotensive range is also a strong predictor of future hypertension. Therefore, we determined whether maximal systolic BP is associated with resting BP. Resting BP was measured in 68 healthy normotensive men on three separate days. The subjects then performed a graded, maximal exercise test on a Monark cycle ergometer. Maximal systolic BP was strongly correlated with resting systolic BP (r = 0·64, P<0·0001). Subjects with elevations in systolic BP during maximal exercise (>220 mmHg) also had higher (P<0·005) resting BP than those without (<220 mmHg). When stepwise regression analyses were performed, systolic BP at rest was a significant independent predictor of maximal systolic BP, explaining over 40% of the variability. These results suggest that exaggerated BP response as a predictor of future hypertension reported in previous studies may be little more than a simple reflection of elevated resting BP. Specifically, these studies should not be interpreted as demonstrating that exercise BP is a better predictor of future hypertension than resting BP alone. In the future, defining the BP `response' to exercise as a change score (i.e. maximal BP minus resting BP) may be advantageous as it permits the effects of exercise to be examined independently of the level of resting BP.     

Role of pulmonary vascular disorder in determining exercise capacity in patients with severe chronic obstructive pulmonary disease

Summary. In patients with chronic obstructive pulmonary disease (COPD), the primary cardiovascular complication is the development of pulmonary hypertension, especially during exercise. The purpose of this study was to determine whether pulmonary vascular disorder plays an important role in determining exercise capacity in patients with severe COPD. Twenty-one male patients with severe COPD (mean FEV₁= 0.91 ? 0.26 1) performed a progressive incremental exercise test, until symptom-limited maximum, to determine maximal exercise capacity, and then a constant-load exercise test for 5 min at a workload (20–60 W) corresponding to 60% of maximal workload during right heart catheterization to characterize the haemodynamic behavior of pulmonary circulation during exercise. The severity of the pulmonary vascular disorder was assessed using the slope of the mean pulmonary arterial pressure (PAP) - cardiac index (CI) relationship during constant-load exercise (P-Q slope). A significant inverse correlation was found between the maximal oxygen consumption (VO_2max) and P-Q slope (r= -0.669), but not between VO_2max and indices of expiratory airflow obstruction. In addition, the P-Q slope was inversely correlated with mixed venous oxygen tension (PvO₂) at the end of constant-load exercise (r= -0–679) and with the change in oxygen delivery relative to oxygen consumption (ΔO₂/ΔVO₂) during constant-load exercise (r= -0.671). These findings suggest that in patients with COPD, the functional impairment of the pulmonary vasculature is associated with disturbance in oxygen transport to the peripheral muscle during exercise, resulting in reduction of exercise capacity. We conclude that pulmonary vascular disorder may be an important factor in determining the exercise capacity of patients with severe COPD.     

Relationship between arterial baroreflex sensitivity and exercise capacity in patients with acute myocardial infarction

To investigate the relationship between arterial baroreflex sensitivity (BRS) and exercise capacity, we examined arterial BRS and its relation to exercise capacity during upright bicycle exercise in 40 uncomplicated patients with acute myocardial infarction. Arterial BRS was measured 3 weeks (20 ± 5 days) after acute myocardial infarction and assessed by calculating the regression line relating phenylephrine‐induced increases in systolic blood pressure to the attendant changes in the R–R interval. All patients underwent graded symptom‐limited bicycle exercise with direct measurements of hemodynamic and metabolic measurements. In all patients, the average arterial BRS was 5·6 ± 2·6 ms mmHg^?1. There were no significant correlations between arterial BRS and hemodynamic measurements at rest. However, arterial BRS was negatively related to systemic vascular resistance at peak exercise (r = ?0·60, P = 0·0001) and percent change increase in systemic vascular resistance from rest to peak exercise (r = ?0·45, P = 0·003), whereas arterial BRS was positively related to cardiac output (r = ?0·48, P = 0·002) and stroke volume at peak exercise (r = 0·42, P = 0·007), and percent change increase in cardiac output (r = ?0·55, P = 0·0002) and stroke volume from rest to peak exercise (r = 0·41, P = 0·008). Furthermore, arterial BRS had modest but significant correlations with peak oxygen consumption (r = ?0·48, P = 0·002) and exercise duration (r = 0·35, P = 0·029), indicating that patients with better arterial BRS have better exercise capacity in patients with acute myocardial infarction. These results suggest that arterial BRS was linked to central and peripheral hemodynamic responses to exercise and hence, contributed to exercise capacity after acute myocardial infraction.     

多巴酚丁胺联合小剂量多巴胺辅助治疗小儿重症肺炎的临床效果

目的探讨多巴酚丁胺联合小剂量多巴胺辅助治疗小儿重症肺炎的效果。方法选取2017年4月至2019年3月我院收治的96例重症肺炎患儿,根据治疗方案的不同将其分为对照组和研究组,各48例。对照组给予常规抗感染方案进行治疗,研究组在对照组基础上给予多巴胺丁胺联合小剂量多巴胺进行治疗。比较两组的治疗效果。结果研究组患儿心率异常缓解时间、呼吸困难缓解时间、肺部干湿啰音改善时间与发热缓解时间明显短于对照组(P<0.05)。研究组的治疗总有效率明显高于对照组(P<0.05)。治疗后7 d,两组IL-6、IL-8和TNF-α水平均显著降低,且研究组低于对照组(P<0.05)。结论多巴酚丁胺联合小剂量多巴胺辅助治疗重症肺炎患儿的疗效显著,能够明显缩短患儿症状与体征改善时间,且能有效控制炎症反应。     

心痛贴对麻醉犬急性心肌梗死的保护作用

目的:观察心痛贴对犬急性心肌梗死的保护作用。方法:24只犬被单纯随机分为空白对照组,心痛贴1.2g,0.6g剂量组,阳性对照4个组,麻醉开胸结扎犬冠状动脉左前降支(LAD)复制急性心肌梗死模型,测定犬心肌缺血程度(∑-ST)、心肌缺血范围(N-ST)、梗死面积及血清酶学变化。结果:心痛贴(XTT)大、小剂量组均可减轻心肌缺血程度和降低缺血范围(P<0.01,P<0.05),缩小心肌梗死面积(P<0.01,P<0.05),降低血清肌酸激酶(CK)及乳酸脱氢酶(LDH)活性(P<0.001,P<0.01)。结论:心痛贴对缺血心肌具有保护作用。     

运动疗法对老年慢性充血性心力衰竭患者的治疗效果

目的　观察运动疗法对老年慢性充血性心力衰竭患者的治疗效果。方法慢性心衰患者106例,分为运动治疗组(54例)和对照组(52例),综合观察患者运动前后的有关指标,并评价运动能力和生存质量。结果　动疗法可促进临床表现的好转,增强患者的运动能力,明显提高患者的生存质量;检测血浆心钠素、内皮素可作为运动观察的可靠指标。结论　动疗法对老年慢性充血性心力衰竭患者安全有效。     

下肢运动训练对外周动脉疾病患者小腿经皮氧分压及运动能力的影响

目的:探讨平板及踏车运动对外周动脉疾病患者小腿经皮氧分压(Tc PO2)及运动能力的影响,为不同人群最适运动处方的制定提供方法与依据。方法:将80例外周动脉疾病患者随机分为对照组(26例)、平板运动组(27例)及踏车运动组(27例),对照组予以常规药物治疗,平板及踏车运动组在对照组的基础上分别予以12周平板运动及踏车运动,3组患者在治疗前后行小腿经皮氧分压、6min步行试验及行走受损问卷(WIQ)评估。结果:治疗前三组患者小腿经皮氧分压基线、6min步行试验及行走受损问卷评估均无显著差异(P0.05);12周运动后,与治疗前相比,对照组患者各项评估较治疗前并无显著性差异(P0.05),而平板及踏车运动组均较治疗前改善(P0.05);组间对比,平板及踏车运动组各项评估均优于对照组(P0.05);平板运动组与踏车运动组相比,两组间经皮氧分压基线并无显著差异(P0.05),平板运动组6min步行距离优于踏车运动组(P0.05),而在行走受损问卷评估中踏车运动组表现出更好的爬梯能力,但两组间差异并不显著(P0.05)。结论:下肢运动能够改善外周动脉疾病患者小腿微循环情况,提高患者的运动能力,同时平板及踏车运动有着相似受益程度,对于不能安全行走及运动耐力较低的患者而言,踏车运动可能更为适合。     

心肺运动试验对COPD的评估价值

采用自行车功率计做功，通过体积描记仪和能耗测试系统，监测３８例男性慢性阻塞性肺疾病（ＣＯＰＤ）患者和３０例正常男性对照者的心肺运动试验，发现运动试验指标与年龄呈负相关；ＣＯＰＤ组做功、每分通气量、摄氧量、ＣＯ２产生量的改变与用力肺活量、最大呼气中段流量、第一秒用力呼气量、呼气流量峰值等反映阻塞性通气障碍的肺功能指标显著相关提示心肺运动试验主要指标的改变可反映阻塞性通气功能障碍，有助于ＣＯＰＤ的评估