Cardiovascular and Ventilatory Responses during Formalized T'ai Chi Chuan Exercise

Abstract

T'ai Chi Chuan (TCC) is a widely practiced Chinese martial art said to physically develop balance and coordination as well as enhance emotional and mental health. TCC consists of a series of postures combined into a sequential movement providing a smooth, continuous, low-intensity activity. The purpose of this study was to examine the ventilatory and cardiovascular responses to the Long Form of Yang's style TCC. In addition, the subjects' TCC responses were compared to their ventilatory and cardiovascular responses during cycle ergometry at an oxygen consumption (VO₂) equivalent to the mean TCC VO₂ Six experienced (M = 8.3 yrs) male TCC practitioners served as subjects with data collected during the Cloud Hand movement of the TCC exercise. Significantly (p < .05) lower responses for ventilatory frequency (Vf) (11.3 and 15.7 breaths min^?1), ventilatory equivalent (VE!VO₂) (23.47 and 27.41), and the ratio of dead space ventilation to tidal volume (VD!VT) (20 and 27%) were found in TCC in comparison to cycle ergometry. The percentage of minute ventilation used for alveolar ventilation was significantly higher during TCC (p < .03) than cycle ergometry, with mean values of 81.1% and 73.1%, respectively. Cardiac output, stroke volume, and heart rate were not significantly different between TCC exercise and cycle ergometry at the same oxygen consumption. We concluded that, during TCC, expert practitioners show significantly different ventilatory responses leading to more efficient use of the ventilatory volume than would be expected from comparable levels of exertion on a cycle ergometer.     

Comparison of physiological responses to graded exercise test performance in outrigger canoeing

Abstract

The aim of this study was to establish a graded exercise test protocol for determining the peak physiological responses of female outrigger canoeists. Seventeen trained female outrigger canoeists completed two outrigger ergometer graded exercise test protocols in random order: (1) 25 W power output for 2 min increasing by 7.5 W every minute until exhaustion; and (2) 25 W power output for 2 min increasing by 15 W every 2 min to exhaustion. Heart rate and power output were recorded every 15 s. Expired air was collected continuously and sampled for analysis at 15-s intervals, while blood lactate concentration was measured immediately after and 3, 5, and 7 min after exercise. The peak physiological and performance variables examined included peak oxygen uptake ([Vdot]O_2peak), minute ventilation, tidal volume, ventilatory thresholds 1 and 2, respiratory rate, respiratory exchange ratio, heart rate, blood lactate concentration, power output, performance time, and time to [Vdot]O_2peak. There were no significant differences in peak physiological responses, ventilatory thresholds or performance variables between the two graded exercise test protocols. Despite no significant differences between protocols, due to the large limits of agreement evident between protocols for the peak physiological responses, it is recommended that the same protocol be used for all comparison testing to minimize intra-individual variability of results.     

The Effects of Breathing 100 Percent Oxygen during Rest,Heavy Work,and Recovery

Abstract

The effects of breathing 100% oxygen on resting, exercise, and recovery oxygen consumptions, pulmonary ventilation volumes, and heart rates were observed on six highly conditioned male athletes. The subjects rode a bicycle ergometer at a heavy work load for five minutes, breathing either normal air or medical oxygen. Ventilation volumes were determined by the open-circuit Douglas bag method, measuring inspired and expired volumes. Gas samples were analyzed for nitrogen and oxygen concentrations on Van Slyke and Beckman gas analyzers, and heart rates were recorded via a telemetry-electrocardiograph system. The results indicated a substantial increase in resting oxygen consumption, a decrease in resting ventilation volume, a marked decline in exercise and recovery ventilation volumes, and an insignificant lowering of the energy cost of exercise during the oxygen experiments. No appreciable differences were noted in heart rates between the oxygen and air experiments.     

Comparison of physiological responses to graded exercise test performance in outrigger canoeing

The aim of this study was to establish a graded exercise test protocol for determining the peak physiological responses of female outrigger canoeists. Seventeen trained female outrigger canoeists completed two outrigger ergometer graded exercise test protocols in random order: (1) 25 W power output for 2 min increasing by 7.5 W every minute until exhaustion; and (2) 25 W power output for 2 min increasing by 15 W every 2 min to exhaustion. Heart rate and power output were recorded every 15 s. Expired air was collected continuously and sampled for analysis at 15-s intervals, while blood lactate concentration was measured immediately after and 3, 5, and 7 min after exercise. The peak physiological and performance variables examined included peak oxygen uptake (VO2peak), minute ventilation, tidal volume, ventilatory thresholds 1 and 2, respiratory rate, respiratory exchange ratio, heart rate, blood lactate concentration, power output, performance time, and time to VO2peak. There were no significant differences in peak physiological responses, ventilatory thresholds or performance variables between the two graded exercise test protocols. Despite no significant differences between protocols, due to the large limits of agreement evident between protocols for the peak physiological responses, it is recommended that the same protocol be used for all comparison testing to minimize intra-individual variability of results.     

An Analysis of Heart Rateesponse to Exercise

Abstract

Heart rate response to exercise and recovery after exercise were studied analytically on the basis that any energy extracted from a muscle must ultimately be supplied by oxidation. Any discrepancy between oxygen supply rate and equivalent oxygen consumption rate was assumed to be made up by utilizing a finite reserve; thus allowing supply to lag consumption at the onset of exercise. Heart rate was assumed and experimentally demonstrated to be linearly related to oxygen supply rate during both steady-state and the transition period after exercise starts or stops. During recovery the withdrawals from reserves are repaid as heart rate returns to normal. Consideration of these factors resulted in an exponential heart rate response equation which closely agreed with observations. Coefficients, evaluated from experimental data, gave average time constants of 1.2 to 1.7 sec. with recovery being slower than response to exercise. Integration of this equation over the exercise range gave an estimate of the deficiency of supply as compared to consumption. A similar integration over the recovery phase indicated that in this range, supply exceeded consumption by at least as much as it was deficient during the exercise phase.     

间歇性低氧刺激对人体最大摄氧量及通气阈值的影响

目的:通过对体育学院大学生进行为期一周的间歇性低氧刺激,观察刺激前后递增负荷运动心率、通气量、摄氧量及定量负荷时血乳酸的变化,探讨间歇性低氧刺激对人体最大摄氧量及通气阈的影响。方法:本实验分两个阶段,每阶段做两次运动负荷。12名体育系男生在实验室常氧条件下在跑台上采用Bruce方法进行递增负荷运动至力竭。间隔3天后进行75%最大摄氧量的定量负荷运动,运动时间为9min,定量负荷后立即进行连续7天,每天1h的12%~10%O2的常压间歇性低氧刺激。低氧刺激完成后第二天再次进行上述两种运动方案。在极限递增负荷至力竭运动前后分别测定心率(HR)、递增负荷至力竭时间(t)、最大摄氧量(VO2max%)、血乳酸(Bla)及定量负荷时Bla等指标。结果:(1)低氧刺激后,递增负荷至力竭运动时HRmax增加(P0.01),VEmax上升(P0.01),呼吸商(R)增加(P0.05),t明显延长(P0.05),Bla明显增加(P0.05),定量负荷运动Bla显著降低(P0.05);(2)间歇性低氧刺激后通气阈时,HR、VE、VO2max%、HRmax%均显著性变化(P0.05),其中VE、VO2max%低氧刺激前后差异非常显著(P0.01)。结论:经过间歇性低氧刺激,受试者在进行递增负荷的力竭性运动时运动时间明显延长,心率在运动后增加,人体通气阈时相对应的心率百分数、最大摄氧量百分比、肺通气量均明显提高,这表明人体有氧耐力和极限负荷运动能力均得到增强。     

The effects of dehydration and rehydration on electrocardiographic and echocardiographic parameters in Greco-Roman wrestlers

Abstract

The effects of exercise training on heart have been widely explored. However, less understood are the effects of dehydration and rehydration on electrocardiographic (ECG) and echocardiographic (Echo) parameters in wrestlers. The aim of this study was to determine the effect of dehydration and rehydration on some ECG and Echo parameters. Fourteen healthy high school wrestlers (age 18.1±2.6 years, weight 77.2±10.2 kg, BMI 25.2±2.9 kg · m^?2; mean±s) were randomly assigned to an experimental (loss of 3–4% of their weight through 10-min bouts in dry sauna) or a control (dry sauna exposure with mineral water proportionate to their body weight loss) group. Blood and urine sampling, 12-lead ECG, and echocardiogram were recorded in euhydration, dehydration, and 18 h after sauna. Moreover, a 6-min high-intensity arm ergometer cranking test (8×15 s intervals at maximum workload and 30 s active recovery) was completed in each of the three stages. Data were analysed with repeated-measures analysis of variance, independent t-tests, and Pearson correlations. Dehydration by 3–4% of body weight in sauna resulted in augmentation of the sum of amplitudes of P waves and QRS complexes (mm), but decreased left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), and stroke volume (ml). As expected, rehydration was associated with recovery of the P wave and ECG parameters. In general, QRS amplitude correlated poorly with LVESV, LVEDV, and P wave, but was inversely related to stroke volume (r=–0.387, P=0.011). In conclusion, dehydration in Greco-Roman wrestlers results in physiological alterations (amplitude of the P wave and QRS complex, LVESV, LVEDV, and stroke volume) of the electrical properties of the passive volume conductor. Further research is necessary to assess the potential for adverse events and appropriateness of this short-term weight loss strategy for young wrestlers or other populations.     

Cardiovascular and ventilatory responses during formalized T'ai Chi Chuan exercise

T'ai Chi Chuan (TCC) is a widely practiced Chinese martial art said to physically develop balance and coordination as well as enhance emotional and mental health. TCC consists of a series of postures combined into a sequential movement providing a smooth, continuous, low-intensity activity. The purpose of this study was to examine the ventilatory and cardiovascular responses to the Long Form of Yang's style TCC. In addition, the subjects' TCC responses were compared to their ventilatory and cardiovascular responses during cycle ergometry at an oxygen consumption (VO2) equivalent to the mean TCC VO2. Six experienced (M = 8.3 yrs) male TCC practitioners served as subjects with data collected during the Cloud H and movement of the TCC exercise. Significantly (p less than .05) lower responses for ventilatory frequency (Vf) (11.3 and 15.7 breaths.min-1), ventilatory equivalent (VE/VO2) (23.47 and 27.41), and the ratio of dead space ventilation to tidal volume (VD/VT) (20 and 27%) were found in TCC in comparison to cycle ergometry. The percentage of minute ventilation used for alveolar ventilation was significantly higher during TCC (p less than .03) than cycle ergometry, with mean values of 81.1% and 73.1%, respectively. Cardiac output, stroke volume, and heart rate were not significantly different between TCC exercise and cycle ergometry at the same oxygen consumption. We concluded that, during TCC, expert practitioners show significantly different ventilatory responses leading to more efficient use of the ventilatory volume than would be expected from comparable levels of exertion on a cycle ergometer.     

Physiological responses to laboratory-based soccer-specific intermittent and continuous exercise

The aim of this study was to devise a laboratory-based protocol for a motorized treadmill that was representative of work rates observed during soccer match-play. Selected physiological responses to this soccer-specific intermittent exercise protocol were then compared with steady-rate exercise performed at the same average speed. Seven male university soccer players (mean - s : age 24 - 2 years, height 1.78 - 0.1 m, mass 72.2 - 5.0 kg, VO 2max 57.8 - 4 ml·kg -1 ·min -1 ) completed a 45-min soccer-specific intermittent exercise protocol on a motorized treadmill. They also completed a continuous steady-rate exercise session for an identical period at the same average speed. The physiological responses to the laboratory-based soccer-specific protocol were similar to values previously observed for soccer match-play (oxygen consumption approximately 68% of maximum, heart rate 168 - 10 beats·min -1 ). No significant differences were observed in oxygen consumption, heart rate, rectal temperature or sweat production rate between the two conditions. Average minute ventilation was greater ( P ? 0.05) in intermittent exercise (81.3 - 0.2l·min -1 ) than steady-rate exercise (72.4 - 11.4l·min -1 ). The rating of perceived exertion for the session as a whole was 15 - 2 during soccer-specific intermittent exercise and 12 - 1 for continuous exercise ( P ? 0.05). The physiological strain associated with the laboratory-based soccer-specific intermittent protocol was similar to that associated with 45 min of soccer match-play, based on the variables measured, indicating the relevance of the simulation as a model of match-play work rates. Soccer-specific intermittent exercise did not increase the demands placed on the aerobic energy systems compared to continuous exercise performed at the same average speed, although the results indicate that anaerobic energy provision is more important during intermittent than during continuous exercise at the same average speed.     

Heart Rate Response to a Modified Harvard Step Test: Males and Females,Age 10–69

Abstract

The residents of an entire community are being examined periodically in an effort to determine the etiologic factors which lead to impaired health. As a part of this study, a submaximal test consisting of stepping onto an 8-inch bench at the rate of 24 steps/ minute for three minutes was administered to 2696 males and 2568 females, aged 10–69. The ECG, from which heart rate (HR) was measured, was recorded before, during, and after the exercise. Resting, exercise, and postexercise HR's are significantly higher for females at all ages. Pre-exercise HR decreases from age 10 to about age 25 in males and females, and shows little age change thereafter. In both males and females the terminal (3 minute) HR decreases from age 10 to 35, remains fairly constant to age 55, and decreases thereafter. The postexercise HR decreases again at age 65 in males and females. Reclining pre-exercise HR is moderately correlated with the exercise and postexercise HR at all ages in males and females. However, there is only a low correlation between either sitting or standing anticipatory HR and exercise and postexercise HR's. The HR's at 2′30” and 3′ during exercise are highly correlated as are the various postexercise HR's with each other at all ages and in both males and females. The correlation of the exercise HR and postexercise HR is moderately high. Percentile ranks for males and females (age 10–69) are given for the 1-minute postexercise HR's.     

Physiological responses to laboratory-based soccer-specific intermittent and continuous exercise

The aim of this study was to devise a laboratory-based protocol for a motorized treadmill that was representative of work rates observed during soccer match-play. Selected physiological responses to this soccer-specific intermittent exercise protocol were then compared with steady-rate exercise performed at the same average speed. Seven male university soccer players (mean +/- s: age 24 +/- 2 years, height 1.78 +/- 0.1 m, mass 72.2 +/- 5.0 kg, VO2max 57.8 +/- 4 ml x kg(-1) x min(-1)) completed a 45-min soccer-specific intermittent exercise protocol on a motorized treadmill. They also completed a continuous steady-rate exercise session for an identical period at the same average speed. The physiological responses to the laboratory-based soccer-specific protocol were similar to values previously observed for soccer match-play (oxygen consumption approximately 68% of maximum, heart rate 168 +/- 10 beats x min(-1)). No significant differences were observed in oxygen consumption, heart rate, rectal temperature or sweat production rate between the two conditions. Average minute ventilation was greater (P < 0.05) in intermittent exercise (81.3 +/- 0.2 l x min(-1)) than steady-rate exercise (72.4 +/- 11.4 l x min(-1)). The rating of perceived exertion for the session as a whole was 15 +/- 2 during soccer-specific intermittent exercise and 12 +/- 1 for continuous exercise (P < 0.05). The physiological strain associated with the laboratory-based soccer-specific intermittent protocol was similar to that associated with 45 min of soccer match-play, based on the variables measured, indicating the relevance of the simulation as a model of match-play work rates. Soccer-specific intermittent exercise did not increase the demands placed on the aerobic energy systems compared to continuous exercise performed at the same average speed, although the results indicate that anaerobic energy provision is more important during intermittent than during continuous exercise at the same average speed.     

模拟全程马拉松跑过程中能量代谢的变化

目的:了解优秀运动员在全程马拉松跑过程中通气量、摄氧量(V·O2)、潮气量、心率、总能耗、糖消耗量、脂肪消耗量以及乳酸产生量等的变化。方法:以1名肯尼亚优秀马拉松运动员为实验对象,在跑步机上以接近于其80%最大摄氧量(V·O2max)强度的18 km·h^-1速度完成全程马拉松跑,并在全过程中通过运动心肺测试系统采集能量代谢相关指标,并与3天前进行的V·O2max测试获得相关指标的最大值进行对比。结果:1)在马拉松过程中,单位时间内的V·O2、通气量、潮气量相对稳定,平均值分别占递增速度V·O2max测试中最大值的75.4%、67.0%、81.0%;2)在不补充水分时,心率从第40 min开始出现逐渐上升的趋势,结束时心率达到最大心率的92.5%,全程平均心率为最大心率的88.8%;3)全程每公斤体重的每公里能耗基本保持稳定,呼吸商在0.9~1.0之间,能量供应以糖的有氧代谢为主,乳酸产生量极少,糖和脂肪消耗总量为8.4 g·kg^-1和0.5 g·kg^-1;4)从静脉血部分指标的变化来看,红细胞总数及其参数变化幅度较小,白细胞总数、单核细胞数以及粒细胞数的增加幅度分别达到了100.9%、142.7%和186.1%。结论:优秀马拉松运动员在全程马拉松跑过程中,动作经济性能够保持相对稳定,补水不足时心率呈上升趋势,能量供应主要以糖的有氧代谢为主,乳酸产生量极少。运动前后红细胞数变化较小,白细胞等免疫相关细胞的变化较大。     

The Effect of Selected Pace Variations on the Oxygen Requirement of Running a 4:37 Mile

Abstract

Nine experienced middle distance runners completed three experimental runs of equal distance and duration on a motor driven treadmill. Each run varied according to pace (steady, fast-slow-fast, and slow-fast), with the individual order of runs rotated to prevent bias in this respect. Heart rate and oxygen consumption measures were taken during rest, exercise and a 30-minute recovery period. Oxygen consumption values for the 30–90 minute recovery period were extrapolated from earlier measured recovery values. Analysis of data indicated that there were no significant differences among the three pace plans in net oxygen intake during the runs. However, the total oxygen debt value for the steady pace was lower than that for either the fast-slow-fast or the slow-fast paces. The total net oxygen requirement for the steady pace was found to be significantly less than that for the other two paces with no significant difference between the fast-slow-fast and slow-fast paces. It was concluded that a steady pace is most efficient for achieving best time in the mile run. Several reasons for individual differences in the oxygen requirement for running a specified effort were discussed.     

中老年知识分子42式太极拳锻炼的血液动力流变学效应

采用XXG－D型心功能测仪对集美老年大学42式太极拳班39名中老年知识分子进行练拳前和练拳1年后在安静状态下的血液动力流变学32个参数的检测。结果表明,坚持太极拳练习可出现：每搏输出量（SV）增加、脉率（PR）减慢、左心能量有效利用率（EWK）提高、心肌耗氧量（HOV）和耗氧指数（HOI）降低等血液动力学中枢效应;收缩压（SP）和平均收缩压（MSP）、总外周阻力（TPR）和标准用阻（SPR）降低等血液动力学外用效应。但对血粘度（η）和微循环状况的改善不具统计学意义。初步观察到42式太极拳练习对血液动力流变学具有双向性调节作用,其机理有待研究。     

A Proposed Test for Determining Physical Working Capacity at the Heart Rate Threshold

Abstract

Forty-four subjects were given an all-out run test on a motor driven treadmill. The times for attaining heart rates of 150, 160, 170, 180 beats per minute were recorded along with measurements of ventilation, oxygen uptake and carbon dioxide production. The correlations between heart rate times and the all-out run times increased with the heart rate, a correlation of .85 calculated at the rate of 180 beats per minute. Using criteria established by Balke, it was demonstrated that the 180 heart rate serves as a valid cut-off point in measuring circulorespiratory capacity under variable exercise stress conditions.     

Influence of Arm Position and Lung Volume on the Center of Buoyancy of Competitive Swimmers

Purpose: The purpose of this study was to determine if anaerobic performance as measured by the Wingate is decremented in elite female athletes when fraction of inspired oxygen is decreased from 20.9% to 10%. Method: Nine collegiate female soccer players (M_weight = 63.2 ± 10 kg, M_height = 164 ± 4.7 cm, M_age = 18.6 ± 0.5 year) performed 1 Wingate test under each condition separated by at least 24 hr. Oxygen consumption was measured breath by breath using a Sensor-Medics metabolic cart. Postexercise blood lactates were measured using the finger-stick method. During normoxic and hypoxic (10% inspired oxygen [O₂]) conditions, participants inhaled air from a 300-L weather balloon during the 30-s test. Results: Peak power, minimum power, average power, postexercise blood lactate, preexercise and postexercise blood O₂ saturation, and total O₂ consumed during exercise and during recovery were not statistically different between conditions. However, the Fatigue Index and peak ventilation were significantly greater during hypoxia than normoxia (35 ± 11% vs. 27 ± 9% &; 91.6 ± 14.2 L/min vs. 75.2 ± 11.1 L/min, respectively, p < .05, Cohen's d = ? 0.80 and ? 1.29, respectively). Ventilation was elevated during hypoxia within 5 s of beginning the Wingate and remained elevated throughout exercise. This increased ventilation was sufficient to maintain oxygen consumption during exercise. Conclusion: Under hypoxic conditions, the ventilatory response to the Wingate test is perhaps more important than aerobic capacity per se in determining whether or not Wingate performance is decremented.     

42式太极拳定量负荷对中老年知识分子心肺机能的影响

采用XXG-D型心功能测试仪和F-Ⅱ型肺活量计对72名集美老年大学学员在42式太极拳定量负荷前、后进行心血管机能26个参数、肺活量（VC）测定和5次肺活量试验（FVCT）。结果表明心血管机能可顺应42式太极拳定量负荷，使脉率（PR）、每搏量（SV）、心搏指数（SI）、心输出量（CO）、心脏指数（CI）、左心搏功指数（LVWI）、收缩压（SP）、平均收缩压（MSP）、脉压（PP）和肺活量(VC)适度升高，有显著性差异（P<0.01）；而心肌耗氧量（HOV）、心肌耗氧指数（HOI）增加较少，无统计学意义（P>0.05）；负荷后总外周阻力（TPR）和标准周阻（SPR）下降，有显著性差异（P<0.01），而第1次VC分别与第4次和第5次VC比较增加组的例数较多，与其它各组有显著性差异（P<0.01）。结果表明42式太极拳练习对中老年知识分子属中、小强度的需氧运动项目，其运动量和运动强度适宜，有助于心血管机能、肺通气量的改善和提高。     

Nasal splinting effects on breathing patterns and cardiorespiratory responses.

The aim of this study was to compare the effects of nasal splinting during different modes of breathing on breathing patterns and cardiorespiratory responses. Ten healthy subjects (4 males, 6 females) performed five maximal treadmill tests while breathing through the nose, nose + dilator, mouth, nose + mouth, and nose + mouth + dilator. Repeated-measures analysis of variance and Tukey HSD revealed no significant differences between trials for maximal oxygen consumption, minute ventilation at an oxygen consumption of 30 ml.kg-1.min-1, carbon dioxide production, respiratory exchange ratio, tidal volume, dead space to tidal volume ratio, or completed treadmill stages to exhaustion. No significant difference was found in subjective dyspnoea ratings between stages of nose versus nose + dilator breathing. Minute ventilation, ventilatory equivalent for oxygen, and breath frequency for nose and nose + dilator versus mouth, nose + mouth, and nose + mouth + dilator were significantly lower. Ventilatory equivalent for carbon dioxide was significantly lower for nose versus mouth, and nose + dilator versus nose + mouth + dilator breathing. End-tidal carbon dioxide was significantly higher in nose versus mouth, nose + mouth, and nose + mouth + dilator breathing, and in nose + dilator versus mouth breathing. Nose breathing revealed a significantly lower heart rate versus nose + dilator, mouth, nose + mouth, and nose + mouth + dilator breathing. These results suggest that nasal splinting during exercise has minimal effects when nasal breathing and no effects when oronasal breathing.