Recovery of pulmonary diffusing capacity after maximal exercise

Abstract

Pulmonary diffusing capacity (Dl_co), together with spirometric variables, arterial oxygen tension (paO₂) and cardiac output were determined before and at intervals after maximal arm cranking, treadmill running and erogmeter rowing. Independent of the type of exercise, Dl_co increased immediately post‐exercise from a median 13.6 (range 7.3–16.3) to 15.1 (9.3–19.6) mmol min^‐1 kPa^‐1 (P <0.01). However, it decreased to 11.6 (6.9–15.5) mmol min^‐1 kPa^‐1 (P <0.01) after 24 h with cardiac output and paO₂ at resting values, and Dl_co normalized after 20 h. Thoracic electrical impedance at 2.5 and 100 kHz increased slightly post‐exercise, indicating a decrease in thoracic fluid balance, and there were no echocardiographic signs of left ventricular failure at the time of the decrease in Dl_co. Also, active muscle (limb) circumference and volume, and an increase in haematocrit from 43.8 (38.0–47.0) to 47.1 (42.7–49.8) (P <0.01), had normalized at the time of the decrease in Dl_co. Vital capacity, forced vital capacity, forced expiratory volume in 1 s, peak and peak mid‐expiratory flows did not change. However, total lung capacity increased from 6.8 (5.0–7.6) to 7.0 (5.1–7.8) litres (P <0.05) immediately after exercise and remained elevated at 6.9 (5.1–8.7) litres (P <0.05) when a decrease in Dl_co was noted. The results demonstrate that independent of the type of maximal exercise, an approximate 15% reduction in Dl_co takes place 2–3 h post‐exercise, which normalizes during the following day of recovery.     

Decrease in pulmonary diffusion capacity after maximal exercise

Oppression of the chest, cough and orthopnea are well known to occur in some athletes after competitions, maybe reflecting an increase in lung water. In order to indicate if lung water increases after maximal exercise we measured pulmonary diffusion capacity before and 2.1 h after a short maximal arm exercise bout in 11 canoeists and showed a decrease of 6.7%. The result may be explained by a calculated 17% increase in alveolar interstitial volume.     

Decrease in pulmonary diffusion capacity after maximal exercise

Oppression of the chest, cough and orthopnea are well known to occur in some athletes after competitions, maybe reflecting an increase in lung water. In order to indicate if lung water increases after maximal exercise we measured pulmonary diffusion capacity before and 2.1 h after a short maximal arm exercise bout in 11 canoeists and showed a decrease of 6.7%. The result may be explained by a calculated 17% increase in alveolar interstitial volume.     

Impaired pulmonary and cardiac function after maximal exercise

The cardiopulmonary response to maximal rowing exercise of short duration was studied in six healthy well-trained oarsmen. The lung diffusing capacity for carbon monoxide was significantly decreased below the pre-exercise value for 2.5 days post-exercise (P less than 0.05). Residual volume (RV) showed a significantly increased value at 30 min of recovery (P less than 0.01) with no change in total lung capacity. There was no significant change in transthoracic electrical impedance following exercise but a decrease may have been masked by the increased RV. The changes in the pulmonary parameters may reflect the occurrence of a transient interstitial lung oedema. Exercise-induced bronchoconstriction may be a part of the cardiopulmonary response as peak expiratory flow rate (PEFR) was significantly reduced at 30 min of recovery. The reason for the increase in pulmonary extravascular water volume may be a marked distension of the lung capillaries due to increased blood volume in the lungs and as a consequence increased vascular permeability. The changes may also be caused by impaired myocardial contractility indicated by a split impedance dZ/dt waveform, not previously described in healthy persons, which occurred in all six subjects immediately following exercise.     

The effects of sodium bicarbonate and pyridoxine-alpha-ketoglutarate on short-term maximal exercise capacity.

The purpose of this study was to determine the effects of the simultaneous use of pyridoxine-alpha-ketoglutarate (PAK) and sodium bicarbonate (NaHCO3) on short-term maximal exercise capacity in eight well-trained male cyclists. The study consisted of the determination of maximal power output and the administration of various combinations of placebos, PAK and NaHCO3, followed by a short-term maximal exercise test. To determine maximal power output (power(max)), the subjects performed a continuous, incremental test on a Monark bicycle ergometer to symptom limited maximum (test 1). To determine the effects of NaHCO3 and PAK on short-term maximal exercise performance, the subjects were administered either placebo (PLA), PAK and sodium bicarbonate (P/B), PAK and placebo (PAK), or sodium bicarbonate and placebo (BIC) prior to performing short-term maximal exercise (test 2). Oral tablets of NaHCO3 and PAK were given in doses of 200 mg kg-1 and 50 mg kg-1 respectively. The subjects pedalled at the power output corresponding to 100% of their VO2 max at 70 rev min-1 until voluntary cessation or until they were unable to maintain pedal revolution rate. Venous blood samples were drawn at rest (RES), cessation of exercise (CES) and after 2 min of recovery (REC) and analysed for lactate, pH and bicarbonate ion concentration. The subjects attained an average maximum power output of 377 +/- 20 W during the graded maximal pre-test (test 1). There were no significant differences between treatments in the ability to sustain power(max) during test 2. During test 2, the subjects were able to sustain power(max) for 7.6 +/- 4.3 min with P/B, 6.7 +/- 2.9 min with PAK, 7.3 +/- 4.9 min with BIC and 6.9 +/- 2.7 min with placebo (mean +/- S.E.). Blood lactate (BLa) was significantly elevated at cessation of exercise and remained elevated during recovery, but there were no significant differences between treatments. Bicarbonate fell significantly during exercise and recovery in each treatment. At rest, bicarbonate levels were significantly higher in both the P/B and BIC than in the PAK or PLA treatments. Pooled data from the P/B and BIC treatments demonstrated a significant increase in pH at rest and end of exercise when compared to PLA treatment. These data suggest that sodium bicarbonate rather than PAK was responsible for this increase. In summary, our data suggest that in the dosages used in this study, administration of sodium bicarbonate or PAK, alone or in combination, is ineffective in increasing short-term maximal exercise capacity.     

Effect of endurance training on blood lactate clearance after maximal exercise.

The aim of this study was to measure serial changes in the rate of blood lactate clearance (gamma2) in response to sequential periods of training and detraining in four male triathletes aged 22-44 years. There were two major phases of training and taper, each lasting 4-5 weeks (training 1 = 5 weeks, taper 1 = 2 weeks, training 2 = 4 weeks and taper 2 = 2 weeks), in preparation for a triathlon competition. The training stimulus absorbed by each subject was carefully quantified from the duration and intensity of the training exercise. A serial weekly measure of each trainee's physical response to training was evaluated as the peak power, termed a 'criterion performance', developed by a subject during a 30 W x min(-1) ramp cycle ergometer test to exhaustion each week. During 30 min of recovery after this test, 13 samples of venous blood were drawn sequentially from a subject to measure the blood lactate recovery curve. The rate constant of blood lactate clearance was estimated by a non-linear least-squares regression technique. In addition, the concurrent time to peak lactate concentration and the peak lactate concentration were also estimated to help define changing lactate kinetics. The criterion performance generally declined throughout each period of incremental training and improved during each taper period, rising iteratively in this way to be clearly above baseline by the end of the second taper. The blood lactate clearance rate increased transiently in early training before declining from the middle of the first training period to the middle of the first taper; thereafter, gamma2 increased above baseline in each trainee throughout the remaining first taper and the major portion of the second training period, decreasing only in the final criterion performance test. The time to peak lactate declined from baseline throughout all phases of training and taper. Peak blood lactate increased in all subjects to the end of the first taper before declining by the end of the second training period, rising again to baseline levels during the second taper. The change in gamma2 was examined relative to the work rate achieved in cycle ergometry above an initial baseline score (deltaCP) and against concurrent peak blood lactate. There was a clear upward shift in gamma2 above baseline throughout the first and second training and taper in two subjects; this was less clear in the remaining two subjects, each of whom had a lower deltaCP. We conclude that this indicates improved lactate clearance, manifest by the change in gamma2 induced by endurance training.     

A test for the measurement of pulmonary diffusion capacity during high-intensity exercise.

The most commonly used technique for the measurement of pulmonary diffusing capacity (DL) is the single-breath hold technique requiring a 10-s breath-hold after the maximal inspiration of carbon monoxide (0.3% CO) and helium (10% He). To measure pulmonary diffusing capacity in our experiments, we had the added advantage of the use of the Gould Pulmonary Function Laboratory that automates the collection and recording of data and the calibration of equipment for each test. However, this technique, DL(CO), is difficult to use during exercise of moderate or elevated intensity because of the lengthy breath-hold. Thus, the purpose of the present study was to compare DL(CO) with 3-s and 5-s breath-holds to a 10-s breath-hold at rest and during moderate and intense exercise in 14 subjects. As expected, an increase in the DL(CO) was observed during moderate and intense exercise when compared to resting values (45.7 +/- 10.0 and 53.0 +/- 7.6 vs 32.1 +/- 7.7 ml CO min-1 mmHg-1). No difference was observed between values for DL(CO) measured at varying breath-hold times at rest (3 s: 32.9 +/- 7.4; 5 s: 32.0 +/- 7.5; 10 s: 31.4 +/- 8.2 ml CO min-1 mmHg-1) or during moderate exercise (3 s: 45.9 +/- 10.1; 5 s: 45.9 +/- 10.6; 10 s: 45.2 +/- 10.4 ml CO min-1 mmHg-1) or intense exercise (3 s: 52.1 +/- 8.3; 5 s: 54.3 +/- 9.3; 10 s: 52.6 +/- 5.2 ml CO min-1 mmHg-1). Reliability coefficients indicated that the use of a 3-s breath-hold was appropriate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of submaximal measures of perceived exertion during bicycle ergometer exercise as predictors of maximal work capacity

Submaximal measures of perceived exertion, aches and pain in the legs, heart rate and blood lactate were made in a bicycle ergometer test. Their predictability of maximal work capacity, measured as Wmax, was studied. Twenty-eight males in good physical condition served as subjects and cycled in a graded exercise test up to a voluntary maximum. The reliability coefficients for both the psychophysical variables--measured on Borg's CR-10 scale--and heart rate were high. Provided that a proposed preliminary division of the subjects into subgroups with regard to their physical fitness was undertaken, the regression analyses showed that the psychophysical variables were the best predictors of Wmax. Linear and curvilinear predictions, graphic or calculated, had lower explained variance but also showed that the psychophysical variables are good predictors of maximal work capacity.     

耐力训练后下丘脑－垂体调节功能对运动机能的影响

研究不同强度的耐力训练对下丘脑－垂体－肾上腺轴－性腺轴与运动有关的几个主要激素的影响，结果表明：不同强度的耐力训练对其合成，释放的作用是不同的。跑台上３５米／分的耐力训练，与其它强度相比，能增加下丘脑－垂体中β－内啡肽（β－ＥＰ）的储备，提高机体的应激能力。降低运动时的应激水平，和乳酸水平，增加有氧供能，从而说明，适宜的耐力训练可提高运动能力，其中β－ＥＰ对性腺轴和肾上腺轴的直接或间接的调控起了重要作用。     

Stress reactivity after maximal exercise: the effect of manipulated performance feedback in endurance athletes

This study was designed to assess the effect of performance feedback on stress reactivity after recovery from maximal exercise. Forty competitive athletes were recruited to complete a maximal exercise test. Performance feedback was manipulated after the exercise test to give four groups: (1) high performance, (2) low performance, (3) accurate feedback and (4) no exercise control. Cardiovascular reactivity was assessed during psychological stress. The results indicate that accurate feedback participants experienced lower relative reactivity to stress (lower mean arterial pressure) than their no-exercise counterparts. These results demonstrate that the stress-buffering effect of exercise extends to maximal exercise. In addition, high-performance participants experienced lower relative reactivity than low-performance participants. Thus, low-performance feedback was sufficient to remove the buffering effect of exercise. There were no differences between the high-performance and accurate feedback conditions, or between the low-performance and control conditions.     

Stress reactivity after maximal exercise: The effect of manipulated performance feedback in endurance athletes

This study was designed to assess the effect of performance feedback on stress reactivity after recovery from maximal exercise. Forty competitive athletes were recruited to complete a maximal exercise test. Performance feedback was manipulated after the exercise test to give four groups: (1) high performance, (2) low performance, (3) accurate feedback and (4) no exercise control. Cardiovascular reactivity was assessed during psychological stress. The results indicate that accurate feedback participants experienced lower relative reactivity to stress (lower mean arterial pressure) than their no-exercise counterparts. These results demonstrate that the stressbuffering effect of exercise extends to maximal exercise. In addition, high-performance participants experienced lower relative reactivity than low-performance participants. Thus, low-performance feedback was sufficient to remove the buffering effect of exercise. There were no differences between the high-performance and accurate feedback conditions, or between the low-performance and control conditions.     

桑拿浴后渐增负荷运动对有氧能力的影响

观察10名身体健康的体育系男子大学生在桑拿高温脱水恢复期，运动时的最大吸氧量(VO2max)、血乳酸浓度(HLa)、通气阈值(VT)的变化，并与常温条件相同运动负荷时相比较，探讨桑拿高温脱水恢复期时的运动对有氧能力的影响。其结果发现在桑拿浴后，恢复期常温条件运动时，VO2max、VT及运动时间都比常温条件增加，同时HR和HLa浓度有所下降，表明桑拿后恢复期可能具有“应激保护”作用。     

尼尔通对足球运动员最大有氧能力的影响

PALIER测试能够较好评定足球运动员的最大有氧能力。尼尔通作为外源性磷酸肌酸能有效提高最大有氧能力，其作用机理是通过供给心肌及骨骼肌细胞代谢所需要的能量和促进膜稳定作用及改善组织微循环等功效来实现的。     

Physiological responses to maximal intermittent exercise: differences between endurance-trained runners and games players.

Six games players (GP) and six endurance-trained runners (ET) completed a standardized multiple sprint test on a non-motorized treadmill consisting of ten 6-s all-out sprints with 30-s recovery periods. Running speed, power output and oxygen uptake were determined during the test and blood samples were taken for the determination of blood lactate and pH. Games players tended to produce a higher peak power output (GP vs ET: 839 +/- 114 vs 777 +/- 89 W, N.S.) and higher peak speed (GP vs ET: 7.03 +/- 0.3 vs 6.71 +/- 0.3 m s-1, N.S.), but had a greater decrement in mean power output than endurance-trained runners (GP vs ET: 29.3 +/- 8.1% vs 14.2 +/- 11.1%, P less than 0.05). Blood lactate after the test was higher for the games players (GP vs ET: 15.2 +/- 1.9 vs 12.4 +/- 1.7 mM, P less than 0.05), but the decrease in pH was similar for both groups (GP vs ET: 0.31 +/- 0.08 vs 0.28 +/- 0.08, N.S.). Strong correlations were found between peak blood lactate and peak speed (r = 0.90, P less than 0.01) and between peak blood lactate and peak power fatigue (r = 0.92, P less than 0.01). The average increase in oxygen uptake above pre-exercise levels during the sprint test was greater for endurance-trained athletes than for the games players (ET vs GP: 35.0 +/- 2.2 vs 29.6 +/- 3.0 ml kg-1 min-1, P less than 0.05), corresponding to an average oxygen uptake per sprint (6-s sprint and 24 s of subsequent recovery) of 67.5 +/- 2.9% and 63.0 +/- 4.5% VO2 max respectively (N.S.). A modest relationship existed between the average increase in oxygen uptake above pre-exercise values during the sprint test and mean speed fatigue (r = -0.68, P less than 0.05). Thus, the greater decrement in performance for the games players may be related to higher glycolytic rates as reflected by higher lactate concentrations and to their lower oxygen uptake during the course of the 10 sprints.     

The effects of frequency of encouragement on performance during maximal exercise testing

The aim of this study was to determine the effects of frequency of verbal encouragement during maximal exercise testing. Twenty-eight participants (12 males, 16 females) aged 20.9 - 1.5 years (mean - s ) performed a maximal exercise test ( V O 2max ) on a treadmill without any verbal encouragement. The participants were matched according to their pre-test V O 2max and placed into either a control group or one of three experimental groups. They performed a second exercise test (post-test) 1 week later. During the second test, the control group received no verbal encouragement; the 20 s (20E), 60 s (60E) and 180 s (180E) encouragement groups received verbal encouragement every 20, 60 and 180 s, respectively, beginning with stage 3 of the exercise test. Relative V O 2max , exercise time, blood lactate concentration, respiratory exchange ratio (RER) and ratings of perceived exertion (RPE) were not significantly different from the first test to the second test for the control group without verbal encouragement and the 180E group that received infrequent encouragement. Post-test values were significantly higher than pre-test values for the 20E and 60E groups. The post-test values of the 20E group were significantly higher than their pre-test values for relative V O 2max ( P ? 0.001), exercise time ( P ? 0.0001), blood lactate concentr . ation ( P ? 0.05), RER ( P ? 0.01) and RPE ( P ? 0.0001); this was also the case for the 60E group for relative V O 2max ( P ? 0.01), blood lactate concentration ( P ? 0.05), RER ( P ? 0.05) and RPE ( P ? 0.05). The results suggest that frequent verbal encouragement (every 20 s and 60 s in the present study) leads to significantly greater maximum effort in a treadmill test than when no encouragement is given or when the encouragement is infrequent (i.e. every 180 s).     

The effects of frequency of encouragement on performance during maximal exercise testing

The aim of this study was to determine the effects of frequency of verbal encouragement during maximal exercise testing. Twenty-eight participants (12 males, 16 females) aged 20.9 +/- 1.5 years (mean +/- s) performed a maximal exercise test (VO2max) on a treadmill without any verbal encouragement. The participants were matched according to their pre-test VO2max and placed into either a control group or one of three experimental groups. They performed a second exercise test (post-test) 1 week later. During the second test, the control group received no verbal encouragement; the 20 s (20E), 60 s (60E) and 180 s (180E) encouragement groups received verbal encouragement every 20, 60 and 180 s, respectively, beginning with stage 3 of the exercise test. Relative VO2max, exercise time, blood lactate concentration, respiratory exchange ratio (RER) and ratings of perceived exertion (RPE) were not significantly different from the first test to the second test for the control group without verbal encouragement and the 180E group that received infrequent encouragement. Post-test values were significantly higher than pre-test values for the 20E and 60E groups. The post-test values of the 20E group were significantly higher than their pre-test values for relative VO2max (P < 0.001), exercise time (P < 0.0001), blood lactate concentration (P < 0.05), RER (P < 0.01) and RPE (P < 0.0001); this was also the case for the 60E group for relative VO2max (P < 0.01), blood lactate concentration (P < 0.05), RER (P < 0.05) and RPE (P < 0.05). The results suggest that frequent verbal encouragement (every 20 s and 60 s in the present study) leads to significantly greater maximum effort in a treadmill test than when no encouragement is given or when the encouragement is infrequent (i.e. every 180 s).     

Dietary salt alters pulmonary function during exercise in exercise-induced asthmatics.

Epidemiological and experimental studies have suggested that dietary salt may play a role in airway responsiveness. We have previously shown that a low salt diet improves and a high salt diet exacerbates post-exercise pulmonary function in individuals with exercise-induced asthma. The aim of this study was to determine the influence of both elevated and restricted salt diets on pulmonary function during exercise in individuals with exercise-induced asthma. Nine men and six women participated in this double-blind, crossover study. The participants entered the study on their normal salt diet and were placed on either a low or high salt diet for 2 weeks. Each diet was randomized, with a 1 week washout period between diets before crossing over to the alternative diet for 2 weeks. The participants underwent treadmill testing at 85% of their age-predicted heart rate on the normal salt diet and at the end of each treatment period. Pulmonary function was assessed during exercise by arterial saturation (ear oximetry) and indirect calorimetry. Twenty-four hour urine collections confirmed compliance with the diets. Arterial saturation was reduced on the high and improved on the low salt diet at higher exercise intensities. Tidal volume and frequency selection during exercise varied with the diets, with a higher tidal volume and lower frequency on the high salt diet, but a lower tidal volume and higher frequency on the low salt diet. This suggested greater airway resistance during the high salt diet. In conclusion, the low salt diet improved and the high salt diet exacerbated pulmonary function during exercise in individuals with exercise-induced asthma. The mechanism of action remains unclear.     

武术、体操女运动员最大有氧工作能力的预测

为准确预测运动员的最大吸氧量,本文对武术、体操女运动员定量工作时的心率、氧脉搏、肺通气量等生理指标,通过计算机分析处理,选择其中较显著的因素建立了三个最优逐步回归方程。通过验证,其预测结果能准确反映运动员的身体工作能力。     

有氧运动对肺动脉高压大鼠肺动脉舒张功能的影响

目的:了解有氧运动对肺动脉高压大鼠肺动脉血管舒张反应的影响。方法:8周大的雄性SD大鼠,随机分为4组,分别是常氧不运动组(N)、常氧运动组(EX)、肺动脉高压不运动组(H)、肺动脉高压运动组(HE)。将大鼠每天暴露在氧浓度为15.6%～16.1%的环境中8小时,每周7次,制作肺动脉高压模型。运动组分别进行8周每天1小时5天/周游泳训练,第9周分离出大鼠肺动脉,检测4组动脉环乙酰胆碱(Ach)诱导的内皮依赖性和硝普钠(SNP)诱导的非内皮依赖性舒张反应。结果:肺动脉高压组大鼠的肺动脉环的内皮依赖性血管舒张功能明显下降,动脉环经NO途径的最大舒张反应明显降低,有氧运动对肺动脉高压大鼠肺动脉的舒张功能有一定的改善作用,与肺动脉高压对照组及常氧运动组比较差异有统计学意义。结论:实验结果证实有氧运动对NO介导的血管舒张功能的有益调节作用,部分被低氧效应所抵消。长期低氧效应超过有氧运动对肺动脉血管的作用这个现象,很可能与NO途径受损有关。     

The effects of repeated maximal voluntary isokinetic eccentric exercise on recovery from muscle damage

This study investigated whether performing repeated bouts of maximal voluntary isokinetic eccentric exercise (MAX1) on 3 (MAX3) and 6 days (MAX6) after the initial bout would produce significant changes in the indirect markers of muscle damage and total work. A secondary purpose was to determine whether participants' psychological maximal effort was equivalent to the physiological maximal effort during muscle soreness. Male university students were assigned randomly to a control group (n = 12) and a group that repeated the exercise (EX; n = 12). The MAX1 was 3 x 10 repetitions of the nondominant elbow flexors on the Cybex 6000 system at a speed of 60 deg/s. The EX group performed the same exercise 3 days and 6 days after MAX1. The range of motion and maximal isometric force (MIF), muscle soreness index, plasma creatine kinase, and glutamic-oxaloacetate transaminase activities were measured before and every 24 hr for 9 days after MAX1 for both groups. MIF was also assessed once before and immediately after each MAX for the EX group. There were no significant changes (p > .05) between the groups for all criterion measures, except for total amount of work (p < .05). It is concluded that strenuous voluntary isokinetic eccentric exercise performed with damaged muscles does not appear to exacerbate damage or influence the recovery process. Although individuals could perform repeated MAXs, the total work performed was significantly reduced. This has practical implications in strength training for coaches and athletes during muscle damage.