心肺运动试验研究进展

心肺运动试验（CPET）是在一定运动负荷下,通过检测代谢与生理指标反映心、肺储备能力以及2者的协调性,进而同步、整体评估运动状态下呼吸系统、心血管系统、神经系统、骨骼肌肉系统等多器官、系统的功能。 CPET综合各种工程及医学技术,具有相对无创、客观定量等优点,目前已成为国际上用于评价心肺储备能力和心肺协调性水平的普遍且重要的临床检测手段,但我国的相关研究较少。从测量参数、试验方法、运动方案、试验设备、评价指标及临床应用等方面对CPET作一综述。     

Comparison of cardiopulmonary responses to two types of dry-land upper-body exercise testing modes in competitive swimmers

In this study we compared cardiopulmonary responses to upper-body exercise in 12 swimmers, using simulation of the front-crawl arm-pulling action on a computer-interfaced isokinetic swim bench and arm cranking on a modified cycle ergometer. Subjects adopted a prone posture; exercise was initially set at 20?W and subsequently increased by 10?W?·?min^?1. The tests were performed in a randomised order at the same time of day, within 72?h. The highest (peak) oxygen consumption (V˙O_2peak), heart rate (HR_peak), blood lactate ([la^?]_peak) and exercise intensity (EI_peak) were recorded at exhaustion. Mean (SEM) peak responses to simulated swimming were higher than those to arm cranking for V˙O_2peak [2.9 (0.2) vs 2.4 (0.1) l?·?min^?1; P?=?0.01], HR_peak [174 (2) vs 161 (2) beats?·?min^?1; P?=?0.03], and EI_peak [122 (6) vs 102 (5) W; P?=?0.02]. However, there were no significant differences in [la^?]_peak [9.6 (0.6) vs 8.2 (0.6) mmol?·?l^?1; P?=?0.08]. Thus simulated swimming is the preferred form of dry-land ergometry for the assessment of swimmers.     

Strategies for cardiopulmonary exercise testing of pectus excavatum patients

The purpose of this paper is to provide strategies for cardiopulmonary exercise testing of pectus excavatum patients. Currently, there are no standardized methods for assessing cardiovascular and pulmonary responses in this population; therefore, making comparisons across studies is difficult if not impossible. These strategies are intended for physicians, pulmonary technicians, exercise physiologists, and other healthcare professionals who conduct cardiopulmonary exercise testing on pectus excavatum patients. By using the strategies outlined in this report, comparisons across studies can be made, and the effects of pectus excavatum on cardiopulmonary function can be assessed with greater detail.     

Haemodynamic response to exercise in healthy young and elderly subjects

Whereas with advancing age, peak heart rate (HR) and cardiac index (CI) are clearly reduced, peak stroke index (SI) may decrease, remain constant or even increase. The aim of this study was to describe the patterns of HR, SI, CI, arteriovenous difference in oxygen concentration (C _a-vO₂), mean arterial pressure (MAP), systemic vascular resistance index (SVRI), stroke work index (SWI) and mean systolic ejection rate index (MSERI) in two age groups (A: 20–30 years, n = 20; B: 50–60 years n = 20. After determination of pulmonary function, an incremental bicycle exercise test was performed, with standard gas-exchange measurements and SI assessment using electrical impedance cardiography. The following age-related changes were found: similar submaximal HR response to exercise in both groups and a higher peak HR in A than in B[185 (SD 9) vs 167 (SD 14) beats?·?min^?1, P??2, P??1?·?m^?2, P?C _a-vO₂ during exercise; higher MAP at all levels of exercise in B; higher SVRI at all levels of exercise in B; lower SWI in B after recovery; higher MSERI at all levels of exercise in A. The decrease in SI with advancing age would seem to be related to a decrease in myocardial contractility, which can no longer be compensated for by an increase in preload (as during submaximal exercise). Increases in systemic blood pressure may also compromise ventricular function but would seem to be of minor importance.     

Adaptive style and physiological reactivity during a laboratory stress paradigm in children with cancer and healthy controls

Repressive adaptation has been conceptualized as one pathway to psychological resilience in children with cancer, but the physiological costs of maintaining a repressive adaptive style are currently unknown. The goal of this study was to examine physiological functioning as a function of adaptive style in children with cancer (N = 120) and healthy controls (N = 120). Children completed self-report measures of state anxiety and defensiveness prior to participating in three verbal stress tasks while monitoring blood pressure, electrocardiogram, and electrodermal response, and rated their anxiety following each task. Findings indicated no consistent differences in baseline indices and physiological reactivity as a function of adaptive style or health status (cancer vs. control). In addition, children identified as having a repressive adaptive style did not exhibit greater verbal-autonomic discrepancy than low-anxious children. In contrast to findings with adults, children with a repressive adaptive style do not appear to experience adverse effects of this coping style in terms of physiological reactivity.     

Physiological unloading of cardiopulmonary mechanoreceptors by posture changes does not influence the pressor response to isometric exercise in healthy humans

Summary In recent studies in humans the role of cardiopulmonary baroreflexes in modulating the cardiovascular responses to isometric exercise (somatic pressor reflex) has been investigated by performing static hand-grip exercise during deactivation of cardiopulmonary receptors produced by low levels of lower body negative pressure; however, findings from these studies have not been consistent. The purpose of this study was to investigate whether a more physiological unloading stimulus of cardiopulmonary baroreceptors, obtained by sequentially changing posture, could influence the pressor response to somatic afferent stimulation induced by isometric, exercise. To accomplish this, ten healthy subjects performed a 2-min isometric handgrip (IHG) at 30% maximal voluntary contraction after 10 min of supine rest and, in rapid sequence, after 10 min of sitting and 10 min of standing, at the time when, owing to their transitory nature, the cardiovascular effects, due to arterial baroreceptor intervention should have been minimal. During IHG arterial pressure (BP_a) was continuously and noninvasively measured to quantify accurately the blood pressure response to IHG both in magnitude and time course. Results showed that the pressor response to IHG was not significantly influenced by change in posture, either in magnitude or in time course. The mean arterial pressure increased by 17.4 (SEM 2.5), 18.6 (SEM 1.2) and 17.0 (SEM 1.3) mmHg in supine, sitting and standing [2.3 (SEM 0.3), 2.5 (SEM 0.2) and 2.3 (SEM 0.2) kPa] positions, respectively. Also the heart rate response to IHG was unaffected by change in posture. Most important, the sum of the separate BP_a responses induced by supine IHG and by posture change from supine to sitting (summation of reflexes) was not significantly different from the pressor response observed during sitting IHG (interaction of reflexes). Likewise, the sum of the separate BP_a. responses induced by sitting IHG and by changing postures from sitting to standing was not significantly different from the pressor response to standing IHG. These data indicate that, under physiological conditions, cardiopulmonary baroreflexes do not exert a significant role in modulating the reflex pressor drive from muscles during isometric exercise in healthy humans.     

Plasma adiponectin response to acute exercise in healthy subjects

Adipose tissue secretes adiponectin, an adipocytokine that is involved in the regulation of insulin sensitivity. Following acute exercise, insulin sensitivity has been shown to increase. Increased adiponectin following exercise may be related to the change in insulin sensitivity. The purpose of the present study was to characterize the effect of a single cycle exercise session on adiponectin and to compare the exercise effects between healthy male and female subjects. Plasma concentrations of adiponectin, tissue necrosis factor-alpha (TNF-), insulin, glucose, and leptin were assessed before and immediately after a 60-minute stationary cycle ergometry session at 65% of O_2max. Male and female subjects were matched for cardiorespiratory fitness and body composition and dietary intake was controlled for the three days prior to the exercise trial. At rest, adiponectin concentration was not associated with percentage body fat, body mass index (BMI), fitness, or resting plasma variables (P>0.05). Following exercise, neither male nor female subjects exhibited changes in adiponectin or leptin concentrations (P>0.05). TNF- exhibited a time main effect increase with exercise (P<0.05), but there were no gender differences. These results suggest that plasma adiponectin concentrations do not change with exercise in healthy male or female subjects. Results are given as mean (SE).     

Exponential protocols for cardiopulmonary exercise testing on treadmill and cycle ergometer

An extended exponential exercise protocol was validated by comparing submaximal and maximal parameters with those obtained by linear protocol. Normal subjects (n = 16, 20–69 years) undertook maximal exercise tests on treadmill and cycle ergometer. The subjects had a wide range of exercise capacity, and all were accommodated by the protocol. Mean oxygen uptake $ (\dot{V}_{{{\text{O}}_{ 2} }} ) $ agreed between protocols at gas exchange anaerobic threshold (θ) (95% CI of difference ?0.1 to +0.06 l min^?1) and at peak (95% CI of difference ?0.1 to +0.1 l min^?1). Mean $ {\hbox{pre-}}\theta \Updelta \dot{V}_{{{\text{O}}_{2} }} /\Updelta {\text{work rate}}(\dot{W}) $ slope on the cycle ergometer agreed between protocols (95% CI of the difference ?0.9 to +0.25 ml min^?1 W^?1). $ {\hbox{Post-}}\theta \Updelta \dot{V}_{{{\text{O}}_{2} }} /\Updelta \dot{W} $ slope was steeper than pre-θ, and steeper by linear than by exponential protocol (P = 0.0001). It is concluded that the exponential protocol is valid for the measurement of submaximal and maximal exercise parameters in subjects with a wide range of exercise capacity.     

Comparison of blood pressure response to isokinetic and weight-lifting exercise

Summary Brachial arterial pressure, oesophageal pressure, and knee joint angle were monitored in eight untrained young men as they performed bilateral leg-press actions (simultaneous hip and knee extension and ankle plantarflexion) against resistance. Single maximal leg-press actions on an isokinetic device evoked mean peak arterial (systolic/diastolic) pressures of 35.4/26.2 and 34.0/23.4 kPa at lever arm velocities of 0.262 and 1.31 rad·s^–1, respectively. The corresponding oesophageal pressures were 13.2 and 10.4 kPa, respectively. Although the peak force was 30% greater, and duration of the action 3–4 times longer at 0.262 than 1.31 rad·s^–1, the arterial and oesophageal pressure responses did not differ. On a weight-lifting machine, a set of repetitions [mean (SEM): 11 (3)] to failure at 80–90% one repetition maximum evoked peak arterial pressures of 45.5/32.8 kPa; the corresponding oesophageal pressure was 15.7 kPa. The peak systolic and diastolic pressures observed during weight-lifting were significantly (P < 0.05) higher than during isokinetic actions at both velocities, whereas oesophageal pressure was more elevated only in relation to isokinetic actions at the higher velocity. These data indicate that resisted leg-press actions cause extreme elevations in arterial blood pressure. The degree of voluntary effort is the major determinant of the blood pressure response, rather than the resistance mode or the type (concentric, eccentric, isometric) of muscle action. Repetitive resistance exercise (e.g. a set of repetitions to failure in weight-lifting) tends to produce greater pressure elevations than isolated, single maximal effort actions.     

The influence of exercise/rest schedule on the physiological and psychophysical response to isometric shoulder-neck exercise

Six female subjects, aged 24-34 years, performed shoulder-neck exercise for 1 h or until they were exhausted by holding out their arms horizontally at 60° to the sagittal plane. One continuous and six intermittent protocols were applied, all with a mean load corresponding to the torque of the arms, i.e. about 15% maximal voluntary contraction (MVC). The intermittent protocols varied according to cycle time (10 s, 60 s, 360 s) and duty cycle (0.33, 0.50, 0.67, 0.83). Electromyogram (EMG), mean arterial blood pressure ( _a), heart rate (f _c) and perceived fatigue were monitored at regular intervals during exercise. Blood concentrations of potassium, lactate and ammonia were determined in pre- and postexercise samples of venous blood. Before and up to 4 h after exercise, measurements were made of MVC, pressure pain threshold, proprioceptive performance, and of EMG, _a and f _c during 1-min arm-holding at 25% MVC. Endurance times ranged from about 10 min to more than 1 h, significantly relating to both cycle time and duty cycle. The _a, f _c EMG amplitude and perceived fatigue increased early during all protocols and continued to increase throughout the exercise period. Duty cycle influenced all of these variables, while only _a and fatigue perception were related to cycle time. Cardiovascular and neuromuscular recovery was incomplete for hours after several of the protocols, as indicated for example by a sensitizised response to the 1-min armholding. The protocols differed substantially as regards the relationship between different responses. Thus, ranking of the protocols in terms of physiological strain was different, depending on the criterion variable. The result stresses the relevance of applying a comprehensive selection of variables when evaluating the responses to intermittent shoulder-neck exercise.     

Physical exercise and quality of life in breast cancer survivors

An important goal for cancer patients is to improve the quality of life (QOL) by maximising functions affected by the disease and its therapy. Preliminary research suggests that exercise may be an effective intervention for enhancing QOL in cancer survivors. Research has provided preliminary evidence for the safety, feasibility, and efficacy of exercise training in breast cancer survivors. The aim of this study was to assess the association between physical exercise and quality of life in a population of female breast cancer survivors, followed up from diagnosis to the off-treatment time period, and investigated about their exercise habits in pre-diagnosis.A total of 212 female breast cancer survivors consecutively registered from January 2002 to December 2006 at a Supportive Care Unit in an Italian Oncology Department were enrolled. Exercise behaviour was assessed by the Leisure Score Index (LSI) of the Godin Leisure-Time Exercise Questionnaire. Patients were asked to report their average weekly exercise for three cancer-related time periods, i.e. pre-diagnosis, during active treatment and off-treatment. Quality of life was assessed by the Italian version of the WHOQOL-BREF standardised instrument. Statistical analysis indicated significant differences across the cancer-relevant time-periods for all exercise behaviour outcomes: the exercise behaviour was significantly lower during both on- and off- treatment than during prediagnosis; exercise during active treatment was significantly lower than during off-treatment. QOL strongly decreases during active treatment. Significant correlations were found between total exercise on- and off-treatment and all QOL indicators. Strenuous exercise is strongly correlated with QOL. Absent/mild exercise seems to be inversely correlated with a positive perception of disease severity and with quality of life on all axes. Need clearly results for inclusion of physical activity programs in comprehensive, complementary treatment regimes for breast cancer patients in Italian oncology departments.     

Thoracic sympathectomy and cardiopulmonary responses to exercise

The purpose was to study the effect of endoscopic thoracic sympathectomy (ETS) for palmar and/or axillary hyperhidrosis on physiological responses at rest, and during sub-maximal and maximal exercise in ten healthy patients (7 females and 3 males 18-40 years old) with idiopathic palmar and/or axillary hyperhidrosis. T2-T3 thoracoscopic sympathectomy was performed using a simplified one stage bilateral procedure. Physiological variables were recorded at rest and during sub-maximal (steady-state) and maximal treadmill exercise immediately prior to and 70 days (+/-7.5, SD) after bilateral ETS. Exercise performance capacity and peak VO(2) were not found to be different following bilateral ETS than prior to the ETS. However, heart rate was significantly reduced at rest (14%), at sub-maximal exercise (12.3%), and at peak exercise (5.7%), together with a significant increase in oxygen pulse (11.8, 12.7, and 7.8%, respectively). The rate pressure product (RPP) was also significantly reduced following the surgical procedure at all three study stages, while all other physiological variables measured remained unchanged. It is suggested that thoracic-sympathetic denervation affects the heart, sweating, and circulation of the respective denervated region but does not affect exercise performance or mechanical/physiologic efficiency, despite a significant reduction in heart rate (both at rest and during exercise). The latter was, most likely, fully compensated by an increase in stroke volume and less likely by an improved muscle O(2) extraction due to more efficient blood distribution, keeping the work-rate and oxygen uptake unaffected.     

Predictors of intentions to use tobacco among adolescent survivors of cancer

OBJECTIVE: To examine the relationship between knowledge of tobacco-related health risks, perceptions of vulnerability to these health risks, and future intentions to use tobacco in a sample of adolescent survivors of cancer. METHODS: Written self-report questionnaires were administered to 46 survivors, 10-18 years of age (61% males, 93.5% Caucasian). RESULTS: Overall, survivors were generally knowledgeable about tobacco-related health risks, perceived themselves to be vulnerable to these health risks, and reported low future intentions to use tobacco. Regression analyses indicated that demographic factors, treatment-related variables, knowledge, and perceived vulnerability explained 28% of the variance in intentions scores, F:(6, 39) = 2.52, p <.05. Age and knowledge were significant predictors, indicating that older adolescent survivors and those with lower knowledge scores reported greater intentions to use tobacco. CONCLUSIONS: Young survivors will benefit from risk counseling interventions that educate them about their susceptibility to specific tobacco-related health risks secondary to their cancer treatment. Intensive tobacco prevention programs that target older adolescents should be developed.     

Acute neurocognitive response to methylphenidate among survivors of childhood cancer: a randomized, double-blind, cross-over trial

OBJECTIVE: To investigate the acute efficacy and adverse side effects of methylphenidate (MPH) among survivors of childhood cancer [acute lymphoblastic leukemia (ALL) or brain tumor (BT)] with learning impairments. METHODS: Participants (N = 122) completed a two-day, in-clinic, double-blind, cross-over trial during which they received MPH (0.60 mg/kg of body weight) and placebo that were randomized in administration order across participants. Performance was evaluated using measures of attention, memory, and academic achievement. RESULTS: A significant MPH versus placebo effect was revealed on a measure of attention, cognitive flexibility, and processing speed (Stroop Word-Color Association Test). Male gender, older age at treatment, and higher intelligence were predictive of better medication response. No significant differences were found for number or severity of adverse side effects as a function of active medication. CONCLUSIONS: MPH shows some neurocognitive benefit and is well tolerated by the majority of children surviving ALL and BT.     

Effect of lowered muscle temperature on the physiological response to exercise in men

Summary The effect of low muscle temperature on the response to dynamic exercise was studied in six healthy men who performed 42 min of exercise on a cycle ergometer at an intensity of 70% of their maximal O₂ uptake. Experiments were performed under control conditions, i.e. from rest at room temperature, and following 45 min standing with legs immersed in a water bath at 12°C. The water bath reduced quadriceps muscle temperature (at 3 cm depth) from 36.4 (SD 0.5)°C to 30.5 (SD 1.7)°C. Following cooling, exercise heart rate was initially lower, the mean difference ranged from 13 (SD 4) beats · min^–1 after 6 min of exercise, to 4 (SD 2) beats · min^–1 after 24 min of exercise. Steady-state oxygen uptake was consistently higher (0.21 · min^–1). However, no difference could be discerned in the kinetics of oxygen uptake at the onset of exercise. During exercise after cooling a significantly higher peak value was found for the blood lactate concentration compared to that under control conditions. The peak values were both reached after approximately 9 min of exercise. After 42 min of exercise the blood lactate concentrations did not differ significantly, indicating a faster rate of removal during exercise after cooling. We interpreted these observations as reflecting a relatively higher level of muscle hypoxia at the onset of exercise as a consequence of a cold-induced vasoconstriction. The elevated steady-state oxygen uptake may in part have been accounted for by the energetic costs of removal of the extra lactate released into the blood consequent upon initial tissue hypoxia.     

A comparison of physical activity of posttreatment breast cancer survivors and noncancer controls

The authors obtained data from 335 breast cancer survivors and 6,880 noncancer controls. They proposed (1) to determine whether, after treatment, the survivors were meeting the Center for Disease Control and Prevention/American College of Sports Medicine recommendations for physical activity and were similar to the controls in physical activity and (2) to compare the modes of activity of the 2 groups in frequency, min/session, and sessions/wk. Adjusted logistic regression analyses revealed that the breast cancer survivors engaged in as much moderate, vigorous, and combined physical activity as the noncancer controls did. However, chi-square analyses showed that survivors engaged in more yard work than the controls did, whereas independent-sample t tests showed that the frequency and the total min/wk of stretching were significantly higher in breast cancer survivors compared with noncancer controls. Findings from the study suggest that breast cancer survivors engage in as much physical activity as controls do, but that the groups differ in specific activities.