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MEYER, T., H. H. W. GABRIEL, M. RATZ, H. J. MULLER, and W. KINDERMANN. Anaerobic exercise induces moderate acute phase response. Med. Sci. Sports Exerc., Vol. 33, No. 4, 2001, pp. 549 -555. Purpose: It was intended to compare the immune reaction after single and repeated short bouts of anaerobic exercise. Methods: Twelve unspecifically trained male subjects (27 6 2 yr, 75 6 2 kg, VO2peak 52 6 2 mL·min -1 ·kg -1 ) performed one 60-s all-out test (SMT) on a cycling ergometer and the same test followed by eight 10-s all-out tests every 5 min (AN-TS). These tests and one control day (Co-Day) were applied in randomized order. At rest and 15 min, 2 h, and 24 h after cessation of exercise the following venous blood parameters were determined: concentration of neutrophils and (CD16 1 -) premacrophages (both flow-cytometrically), interleukin 6 and 8 (IL-6, IL-8), C-reactive protein (CRP) and cortisol. Results: Two hours after cessation of exercise the neutrophils increased stronger after AN-TS than after SMT (P , 0.01). The peak in the number of premacrophages occurred earlier after SMT (15 min post; P , 0.01 to Co-Day) than after AN-TS (2 h post; P , 0.05 to Co-Day). IL-6 was elevated at 15 min and 2 h after AN-TS (P , 0.01 to SMT and Co-Day) but only slightly 2 h after SMT (P , 0.01 to Co-Day). There were no significant changes in IL-8. CRP was the only elevated parameter 24 h postexercise exclusively after AN-TS (P , 0.05 to Co-Day). Conclusion: Repeated short anaerobic bouts of cycling lead to an acute phase response, which is more pronounced than after a single bout. Athletes should take care in performing such training sessions several times a week because signs

This study determined whether exercise (30 min)-rest (10 min) cycles alter physiologic tolerance to uncompensable heat stress (UCHS) when outdoors in the desert. In addition, the relationship between core temperature and exhaustion from heat strain previously established in laboratory studies was compared with field studies.Twelve men completed four trials: moderate intensity continuous exercise (MC), moderate intensity exercise with intermittent rest (MI), hard intensity continuous exercise (HC), and hard intensity exercise with intermittent rest (HI). UCHS was achieved by wearing protective clothing and exercising (estimated at 420 W or 610 W) outdoors in desert heat.Heat Stress Index values were 200%, 181%, 417%, and 283% for MC, MI, HC, and HI, respectively. Exhaustion from heat strain occurred in 36 of 48 trials. Core temperatures at exhaustion averaged 38.6 +/- 0.5 degrees, 38.9 +/- 0.6 degrees, 38.9 +/- 0.7 degrees, and 39.0 +/- 0.7 degrees C for MC, MI, HC, and HI, respectively. Core temperature at exhaustion was not altered (P0.05) by exercise intensity or exercise-rest cycles and 50% of subjects incurred exhaustion at core temperature of 39.4 degrees C. These field data were compared with laboratory and field data collected over the past 35 years. Aggregate data for 747 laboratory and 131 field trials indicated that 50% of subjects incurred exhaustion at core temperatures of 38.6 degrees and 39.5 degrees C, respectively. When heat intolerant subjects (exhaustion38.3 degrees C core temperature) were removed from the analysis, subjects from laboratory studies (who underwent short-term acclimation) still demonstrated less (0.8 degrees C) physiological tolerance than those from field studies (who underwent long-term acclimatization).Exercise-rest cycles did not alter physiologic tolerance to UCHS. In addition, subjects from field studies demonstrate greater physiologic tolerance than subjects from laboratory studies.

We measured substrate utilization during exercise performed with water (W), exogenous glucose (G), and exogenous fructose plus glucose (FG) ingestion in boys age 10–14 yr. Subjects ( n = 12) cycled for 90 min at 55% maximal O2uptake while ingesting either W (25 ml/kg), 6% G (1.5 g/kg), or 3% F plus 3% G (1.5 g/kg). Fat oxidation increased during exercise in all trials but was higher in the W (0.28 ± 0.023 g/min) than in the G (0.24 ± 0.023 g/min) and FG (0.25 ± 0.029 g/min) trials ( P = 0.04). Conversely, total carbohydrate (CHO) oxidation decreased in all trials and was lower in the W (0.63 ± 0.05 g/min) than in the G (0.78 ± 0.051 g/min) and FG (0.74 ± 0.056 g/min) trials ( P = 0.009). Exogenous CHO oxidation, as determined by expired13CO2, reached a maximum of 0.36 ± 0.032 and 0.31 ± 0.030 g/min at 90 min in G and FG, respectively ( P = 0.04). Plasma insulin levels decrease during exercise in all trials but were twofold higher in G than in W and FG ( P < 0.001). Plasma glucose levels decreased transiently after the onset of exercise in all trials and then returned to preexercise values in the W and FG (∼4.5 mmol/l) trials but were elevated by ∼1.0 mmol/l in the G trial ( P < 0.001). Plasma lactate concentrations decreased after the onset of exercise in all trials but were lower by ∼0.5 mmol/l in W than in G and FG ( P = 0.02). Thus, in boys exercising at a moderate intensity, the oxidation rate of G plus F is slightly less than G alone, but both spare endogenous CHO and fat to a similar extent. In addition, compared with flavored W, the ingestion of G alone and of G plus F delays exhaustion at 90% peak power by ∼25 and 40%, respectively, after 90 min of moderate-intensity exercise.

The purpose of this study was to assess the relationship between whole-body leucine oxidation and oxygen consumption during steady-state exercise. Our hypothesis was that leucine oxidation will be responsive to increased whole-body energy needs.Sixteen healthy individuals (7 women and 9 men) were infused with a stable isotope of leucine and, for comparison purposes, lysine during 60 min of moderate-intensity exercise.Leucine oxidation was increased (P0.05) and nonoxidative leucine disposal was decreased (P0.05), whereas leucine and lysine rate of appearance remained unchanged (P = NS) during exercise. Linear regression analysis indicated a modest relationship between leucine oxidation and steady-state oxygen consumption (R = 0.69; P0.003) during steady-state exercise. The coefficient of determination (R(2) = 0.49) indicates that approximately half of the variance in whole-body leucine oxidation during exercise can be explained by whole-body oxygen consumption.In a statistically appropriate sample size of humans whose dietary intake was controlled, the whole-body rate of leucine oxidation during exercise was only partially influenced by energy demands.

At the Third Pan-American Congress of Sport Physicians in Chicago in 1959 we reported the physiological and clinical significance of the spiroergometric determination of the aerobic-anaerobic turnover point for judging the performance of sick and healthy persons for the first time. In this context a distinction was made between a ventilatory and a lactate-related (arterial blood) method of determination. We called the former method the 'point of optimal ventilatory efficiency (PoW)', and the latter one 'endurance performance limit'. In the 1950s the clinical spiroergometric examination of patients and athletes for the determination of the aerobic performance capacity was consistently based on the measurement of the maximal oxygen uptake. As entering the individual border area of the performance capacity of a patient with, for example, cardiopulmonary disease, can provoke accidents, we started to think about a criterion in connection with submaximal work in 1954. Determination of pyruvate and lactic acid in the venous blood did not prove to be a valid parameter. If the spiroergometric values were entered into a coordinate system the most striking similarities during increasing exercise would become evident between the curve of the minute ventilation and the curve of the arterial lactate. The findings were interpreted as follows: during lower grades of performance the oxygen demand in the working muscle cells was saturated, whereas in the case of increasing exercise intensity an additional anaerobic metabolism was necessary. We termed the maximal work load which was covered nearly completely aerobically as the PoW and designated heart frequency at this point as 'pulse endurance limit'. The determination of the parameter was derived in the coordinate system with a tangent to the curve of the minute ventilation as well as to the curve of the arterial lactate. The results of patients and athletes were first published in 1959.

We performed maximal exercise tests on 6 men using a bicycle ergometer and then measured the ferric-reducing ability in plasma to clarify the relationship between antioxidant status and exercise intensity. The ferric-reducing ability showed a rectilinear increase with the increase in exercise intensity, whereas the generation of hydroxyl radicals showed a decrease with the increase in exercise intensity. Also, the generation of hydroxyl radicals showed a symmetrical correlation to lactate level in plasma. These results suggest that antioxidant ability is enhanced with an increase in exercise intensity, and that the lactate level, which increases with physical exercise, may act as a scavenger of free radicals.

Reports concerning the evaluation of therapeutic ergometer training are scarce. Most articles deal with cyclists. The longer the duration of the exercise, the lower the cadence should be. Well-trained cyclists use higher cadences than others because of their skill and coordination. At higher cadences, it is more difficult to direct forces optimally; on the other hand, the peak force generated per pedal thrust decreases with increasing cadence. A higher cadence also means a higher heart rate, ventilation, oxygen uptake and blood lactate concentration. Lowest oxygen uptake and highest efficiency shift to higher frequencies with increasing work load. There are some differences in stress response (central hemodynamics) with regard to pedal speed in normal individuals and in patients suffering from cardiac disease. For non-cyclists, the subjective rating of perceived exertion is supposed to be minimal between 60 and 80 rpm. Patients with coronary heart disease usually rate the exertion higher than do n...

The purpose of this study was to examine the effect of regular CHO beverage ingestion and restricted fluid intake on various salivary parameters during prolonged cycle exercise.In a randomized block design, 15 recreationally active men cycled for 2 h at 60% VO2max on three occasions, separated by 1 wk. On the CHO and placebo (PLA) treatments, subjects consumed either a glucose (60 g x L(-1)) or placebo drink before (400 mL), during (150 mL every 15 min), and after (400 mL) the exercise. On the restricted fluid intake (RFI) treatment subjects were given a total of 200 mL of placebo fluid to take as desired every 15-min during the exercise. Timed, unstimulated saliva samples were collected preexercise, at 1, 1.5, and 2 h of exercise and at 1 h postexercise. Blood samples were obtained from a subset of 8 subjects preexercise, postexercise, and at 1 h postexercise.Postexercise plasma glucose levels were 18% and 20% lower on the PLA and RFI treatments, respectively, compared with the CHO treatment (P0.01). Saliva flow rates were significantly higher on the CHO treatment compared with the RFI treatment at 1.5 h and 2 h of exercise (P0.01 and P0.05, respectively). Salivary IgA (s-IgA) concentration was significantly lower on the CHO treatment compared with the RFI treatment throughout the exercise (P0.05). No other differences were seen between treatments for either saliva flow rate or s-IgA concentration. Neither s-IgA secretion rate, alpha-amylase activity, nor alpha-amylase secretion rate were affected by treatment.These findings suggest that CHO and fluid intake influence the s-IgA and saliva flow rate response to prolonged submaximal exercise.

To assess i) the reproducibility of peak power output recorded during a maximal aerobic power test (MAP), and ii) its validity to predict endurance performance during a field based 16.1-km time trial (16.1-km TT).Two studies were completed: for part I, nine subjects performed three MAP tests; for part II, 16 subjects completed a MAP test and 16.1-km TT. Power output was recorded using an SRM power meter and was calculated as peak power output (PPO) recorded during 60 s of MAP and mean power output for the 16.1-km TT (16.1-km TT(PO)).There was no difference between PPO recorded during the three MAP trials, mean coefficient of variation for individual cyclists was 1.32% (95%CI = 0.97-2.03), and test-retest reliability expressed as an intraclass correlation coefficient was 0.99 (95%CI = 0.96-1.00). A highly significant relationship was found between PPO and 16.1-km TT(PO) (r = 0.99, P0.001) but not for PPO and 16.1-km TT time (r = 0.46. P0.05).The results show that PPO affords a valid and reliable measure of endurance performance which can be used to predict average power during a 16.1-km TT but not performance time.

The purpose of the present study was to determine the electromyographic (EMG) and mechanomyographic (MMG) responses to cycle ergometry at critical power (CP). Seven moderately active males (25 ± 3 years) completed a 60-min trial at their CP estimated from a nonlinear, 3 parameter regression model. EMG and MMG amplitudes were recorded from the vastus lateralis during 60-min continuous rides at CP. The mean CP was 175 ± 25 W, which represented 56 ± 5% of the subjects' peak power outputs. The results indicated that the slope coefficient for the EMG amplitude versus time relationship was not significantly different from zero; however, MMG amplitude decreased significantly over the 60 min. This dissociation between the electrical (EMG) and mechanical (MMG) aspects of muscular activity during cycle ergometry may be due to neuromuscular changes associated with "muscle wisdom" or changes in muscular compliance. Key words: cycle ergometry, fatigue, muscle wisdom, [Formula: see text] slow component

Based on the resistance-rpm relationship for cycling, which is not unlike the force-velocity relationship of muscle, it is hypothesized that the cadence which requires the minimal muscle activation will be progressively higher as power output increases.To test this hypothesis, subjects were instrumented with surface electrodes placed over seven muscles that were considered to be important during cycling. Measurements were made while subjects cycled at 100, 200, 300, and 400 W at each cadence: 50, 60, 80, 100, and 120 rpm. These power outputs represented effort which was up to 32% of peak power output for these subjects.When all seven muscles were averaged together, there was a proportional increase in EMG amplitude each cadence as power increased. A second-order polynomial equation fit the EMG:cadence results very well (r2 = 0.87- 0.996) for each power output. Optimal cadence (cadence with lowest amplitude of EMG for a given power output) increased with increases in power output: 57 +/- 3.1, 70 +/- 3.7, 86 +/- 7.6, and 99 +/- 4.0 rpm for 100, 200, 300, and 400 W, respectively.The results confirm that the level of muscle activation varies with cadence at a given power output. The minimum EMG amplitude occurs at a progressively higher cadence as power output increases. These results have implications for the sense of effort and preferential use of higher cadences as power output is increased.

Power tillers (single axle, two-wheel hand tractors) are widely used for paddy field cultivation in Thailand. Currently, over one million power tillers are being used as they suit both the economical and physical conditions of paddy farming in developing countries. Controlling these hand tractors while walking behind is often hard work. Safety and health concerns associated with the use of these machines have not been well documented. This study was aimed at evaluating the physical response of operators during various operations by power tillers in paddy field. The most popular power tiller model in Thailand was used for this investigation. Field tests were conducted to determine the physical response of operators while using this machine. The response was assessed through measurement of operator heart rates during different operations. The comfort, working posture and the task were also evaluated. The physical work capacity was established with the help of a bicycle ergometer. The field operations carried out were first-plowing, second-plowing and harrowing. The tillage equipment used were moldboard plow, disc plow and peg tooth harrow. A statistical analysis was conducted to compare the effects of environmental factors and working intensity in each activity and results were compared with the standards. It was observed that the physical response during some of the operations exceeded the physical work capacity of the operators. It was noticed that the excessive physiological response was contributed by power tiller use as well as environmental factors. Working with power tiller in muddy paddy fields in a hot and humid climate also contributed to excessive workload. Surface conditions in the field also had a direct effect on physiological response of the operator. Energy cost during wetland operation was also due to unfavorable working conditions. Some ways to improve the design of the power tiller to make it more comfortable for the operator were suggested.

Based on cross-sectional data, we recently reported that, in contrast to the prevailing view, the rate of decline in maximal oxygen consumption (V˙o 2 max) with age is greater in physically active compared with sedentary healthy women. We tested this hypothesis in men using a meta-analytic study ofV˙o 2 max values in the published literature. A total of 242 studies (538 subject groups and 13,828 subjects) met the inclusion criteria and were arbitrarily separated into sedentary (214 groups, 6,231 subjects), active (159 groups, 5,621 subjects), and endurance-trained (165 groups, 1,976 subjects) populations. Body fat percent increased with age in sedentary and active men ( P < 0.001), whereas no change was observed in endurance-trained men.V˙o 2 max was inversely and strongly related to age within each population ( r = −0.80 to −0.88, all P < 0.001) and was highest in endurance-trained and lowest in sedentary populations at any age. Absolute rates of decline inV˙o 2 max with age were not different ( P > 0.05) in sedentary (−4.0 ml ⋅ kg−1 ⋅ min−1 ⋅ decade−1), active (−4.0), and endurance-trained (−4.6) populations. Similarly, there were no group differences ( P > 0.05) in the relative (%) rates of decline inV˙o 2 max with advancing age (−8.7, −7.3, and −6.8%/decade, respectively). Maximal heart rate was inversely related to age within each population ( r = −0.88 to −0.93, all P < 0.001), but the rate of age-related reduction was not different among the populations. There was a significant decline in running mileage and speed with advancing age in the endurance-trained men. The present cross-sectional meta-analytic findings do not support the hypothesis that the rate of decline inV˙o 2 max with age is related to habitual aerobic exercise status in men.

The present study examined the sensitivity of carnitine palmitoyltransferase I (CPT I) activity to its inhibitor malonyl-CoA (M-CoA), and simulated metabolic conditions of rest and exercise, in aerobically trained and untrained humans. Maximal CPT I activity was measured in mitochondria isolated from resting human skeletal muscle. Mean CPT I activity was 492.8 ± 72.8 and 260.8 ± 33.6 μmol ⋅ min−1⋅ kg wet muscle−1in trained and untrained subjects, respectively (pH 7.0, 37°C). The sensitivity to M-CoA was greater in trained muscle; the IC50for M-CoA was 0.17 ± 0.04 and 0.49 ± 0.17 μM in trained and untrained muscle, respectively. The presence of acetyl-CoA, free coenzyme A (CoASH), and acetylcarnitine, in concentrations simulating rest and exercise conditions did not release the M-CoA-induced inhibition of CPT I activity. However, CPT I activity was reduced at pH 6.8 vs. pH 7.0 in both trained and untrained muscle in the presence of physiological concentrations of M-CoA. The results of this study indicate that aerobic training is associated with an increase in the sensitivity of CPT I to M-CoA. Accumulations of acetyl-CoA, CoASH, and acetylcarnitine do not counteract the M-CoA-induced inhibition of CPT I activity. However, small decreases in pH produce large reductions in the activity of CPT I and may contribute to the decrease in fat metabolism that occurs during moderate and intense aerobic exercise intensities.

For patients who have recently had a myocardial infarction (MI), domestic activities may demand a considerable and potentially hazardous amount of effort. The aim of this study was to analyse the cardiovascular load due to common household tasks. A method for measuring the workload of six standardized domestic activities was developed and tested in six healthy volunteers. The method was then used on 21 women who had had a recent MI. The women performed the test at their usual working pace. Heart rates and Borg rates of perceived exertion during these activities were compared with the values obtained at exercise testing (ET) on a bicycle ergometer before discharge from hospital after the acute MI and at a maximal ET 6 weeks after discharge. The results of a maximal ET in 16 women with non-recent coronary events were used as reference values. It was shown that resumption of common domestic work after a recent MI is indeed physically demanding. In 9 of the 21 patients, heart rates during domestic work, espec...

We tested the hypothesis that an elevation in albumin synthetic rate contributes to increased plasma albumin content during exercise-induced hypervolemia. Albumin synthetic rate was measured in seven healthy subjects at 1–5 and 21–22 h after 72 min of intense (85% peak oxygen consumption rate) intermittent exercise and after 5 h recovery in either upright (Up) or supine (Sup) postures. Deuterated phenylalanine (d5-Phe) was administrated by a primed-constant infusion method, and fractional synthetic rate (FSR) and absolute synthetic rate (ASR) of albumin were calculated from the enrichment of d5-Phe in plasma albumin, determined by gas chromatography-mass spectrometry. FSR of albumin in Up increased significantly ( P < 0.05) from 4.9 ± 0.9%/day at control to 7.3 ± 0.9%/day at 22 h of recovery. ASR of albumin increased from 87.9 ± 17.0 to 141.1 ± 16.6 mg albumin ⋅ kg body wt− 1 ⋅ day− 1. In contrast, FSR and ASR of albumin were unchanged in Sup (3.9 ± 0.4 to 4.0 ± 1.4%/day and 74.2 ± 8.9 to 85.3 ± 23.9 mg albumin ⋅ kg body wt− 1 ⋅ day− 1at control and 22 h of recovery, respectively). Increased albumin synthesis after upright intense exercise contributes to the expansion of greater albumin content and its maintenance. We conclude that stimuli related to posture are critical in modulating the drive for albumin synthesis after intense exercise.

This study compared the physiological responses and the mechanical efficiency during both arm cranking exercise and leg pedaling exercise with identical work loads, and determined whether arm cranking or unilateral leg pedaling performance could be used to estimate bilateral pedaling exercise capacity. Seven healthy adult males (mean age: 32 (27-36) years old) participated in this study. Arm cranking and leg pedaling exercise tests were carried out using an identical electrically controlled bicycle ergometer. The cranking/pedaling rate was set at 60 rpm. Exercise was performed under the following conditions: Bilateral leg pedaling (BLP), Unilateral leg pedaling (ULP), Bilateral arm cranking (BAC), and Unilateral arm cranking (UAC). By ramp load protocol in gradually increasing 20 W/min stages, . peak oxygen uptake (peak VO2) and peak heart rate (peak HR) were obtained using BLP, ULP, BAC, and UAC. The oxygen uptake and heart rate obtained using BLP, ULP, BAC, and UAC were compared under three exercise work loads (20 W, 40 W, 60 W). In comparison with ULP and UAC, the values of . peak VO2 and peak HR in BLP and BAC were high, and the response to the 20 W to 60 W exercise intensities rose in tandem with work load. Differences in physiological response due to disparities in the exerted muscle mass became large and showed a rising trend, particularly in ULP and UAC. There were . no significant correlations between BLP and the other types of exercise (BAC, ULP, UAC) in peak VO2 and peak HR. In conclusion, the physiological responses in bilateral and unilateral arm/leg exercise at an identical work load depend on the amount of muscle mass exerted. It is hard to estimate the aerobic

The Na+-K+-ATPase plays an important role in the maintenance of electrolyte balance in the working muscle and thus may contribute to endurance performance. This study aimed to investigate the associations between genetic variants at the Na+-K+-ATPase α2 locus and the response (Δ) of maximal oxygen consumption (V˙o2 max) and maximal power output (W˙max) to 20 wk of endurance training in 472 sedentary Caucasian subjects from 99 families. V˙o2 maxandW˙maxwere measured during two maximal cycle ergometer exercise tests before and again after the training program, and restriction fragment length polymorphisms at the Na+-K+-ATPase α2 (exons 1 and 21–22 with Bgl II) gene were typed. Sibling-pair linkage analysis revealed marginal evidence for linkage between the α2 haplotype and ΔV˙o2 max( P= 0.054) and stronger linkages between the α2 exon 21–22 marker ( P = 0.005) and α2 haplotype ( P = 0.003) and ΔW˙max. In the whole cohort, ΔV˙o2 maxin the 3.3-kb homozygotes of the exon 1 marker ( n = 5) was 41% lower than in the 8.0/3.3-kb heterozygotes ( n = 87) and 48% lower than in the 8.0-kb homozygotes ( n = 380; P = 0.018, adjusted for age, gender, baselineV˙o2 max, and body weight). Among offspring, 10.5/10.5-kb homozygotes ( n = 14) of the exon 21–22 marker showed a 571 ± 56 (SE) ml O2/min increase inV˙o2 max, whereas the increases in the 10.5/4.3-kb ( n = 93) and 4.3/4.3-kb ( n= 187) genotypes were 442 ± 22 and 410 ± 15 ml O2/min, respectively ( P = 0.017). These data suggest that genetic variation at the Na+-K+-ATPase α2 locus influences the trainability ofV˙o2 maxin sedentary Caucasian subjects.

The perception of pain in three groups of patients with angina pectoris has been studied. All patients went through a bicycle ergometer test with an increase of 10 watt each minute. Heart rates and ratings of pain were collected towards the end of each work load. Reliable results of diagnostic interest were obtained. The rating procedure is discussed and a new category rating scale with ratio properties is also presented.

〔目的〕安楽姿勢を応用した，体幹前傾を伴う上肢支持姿勢で自転車エルゴメータを駆動し，呼吸反応からその姿勢の特徴と効果を明らかにすることである。〔対象〕若年健常成人9名（年齢23.1±0.8歳）とした。〔方法〕体幹を前傾しハンドルで上肢を支持した姿勢（TF群）と，ハンドルを握った姿勢（HH群）の2群において，ATレベルで20分間の心拍数一定の定常負荷を施行し，呼吸反応を比較した。〔結果〕TF群は，呼気時間の延長を伴い呼吸数が少なく，換気効率が優れていた。〔結語〕TF群の駆動姿勢は安楽姿勢同様の身体的特徴を認め，慢性呼吸不全患者に特徴的な，浅く速い呼吸を呈する症例が自転車エルゴメータを継続するうえで有益であることが示唆された。

We propose that variations in fat and carbohydrate (CHO) oxidation by working muscle alter O2uptake (V˙o2) kinetics. This hypothesis provides two predictions: 1) the kinetics should comprise two exponential components, one fast and the other slow, and 2) their contribution should change with variations in fat and CHO oxidation, as predicted by steady-state respiratory exchange ratio (RER). The purpose of this study was to test these predictions by evaluating theV˙o2kinetic model:V˙o2( t) = αR+ αF{1 − exp[( t − TD)/−τF]} + αC{1 − exp[( t − TD)/−τC]} for short-term, mild leg cycling in 38 women and 44 men, whereV˙o2( t) describes the time course, αRis resting V˙o2, t is time after onset of exercise, TD is time delay, αFand τFare asymptote and time constant, respectively, for the fast (fat) oxidative term, and αCand τCare the corresponding parameters for the slow (CHO) oxidative term. We found that 1) this biexponential model accurately described the V˙o2kinetics over a wide range of RERs, 2) the contribution of the fast (αF, fat) component was inversely related to RER, whereas the slow (αC, CHO) component was positively related to RER, and 3) this assignment of the fast and slow terms accurately predicted steady-state respiratory quotient and CO2output. Therefore, the kinetic model can quantify the dynamics of fat and CHO oxidation over the first 5–10 min of mild exercise in young adult men and women.

The accumulated O2, calculated by an extrapolation procedure from measurements of the O2 uptake at moderate powers, has been suggested as a measure of the anaerobic energy release during high intensity exercise. While some suggest that repeated 10-min bouts are required to establish the relationships in question, other use bouts of shorter durations. The purpose of this study was to examine how different exercise durations influence the calculated accumulated O2 deficit.Eight endurance trained male cyclists with the following characteristics (Mean +/- SE): age, 25 +/- 3 yr; weight, 69.9 +/- 1.7 kg: height, 178.2 +/- 1.0 cm; and VO2max 57.5 +/- 2.4 mL x kg(-1) x min(-1) volunteered for participation in this study. The O2 uptake was measured at 2-4, 4-6, 6-8, and 8-10 min of exercise at ten different constant powers. These O2 uptakes were used to establish four relationships between the power and O2 demand for each subject. On a separate day the subjects cycled at a power of 336 +/- 42 W (corresponding to about 110% of the maximal O2 uptake) for 296 +/- 43 s to exhaustion while the O2 uptake was measured continuously. For each subject the accumulated O2 deficit was determined from the different relationships.The accumulated O2 deficit determined from the relationships from the 2 to 4-min exercises in the pretests were significantly less than the value calculated from the relationships obtained after the 8-10 min of exercise at constant power, the values being 39.6 +/- 11.6 mL O2 eq x kg(-1) and 53.4 +/- 14.6 mL O2 eq x kg(-1), respectively.This study suggests that reducing the exercise duration used in the pretests to establish the relationships between power and O2 demand from 10 min may lead to a too low accumulated O2 deficit.

Is determination of exercise intensities as percentages of VO2max or HRmax adequate? Med. Sci. Sports Exerc., Vol. 31, No. 9, pp. 1342-1345, 1999. Often exercise intensities are defined as percentages of maximal oxygen uptake (VO2max) or heart rate (HRmax).Purpose:The purpose of this inves

Resume Objectifs L'objet de cette etude etait de determiner les effets d'une charge orale en glucose (0,5 g.kg−1) sur les reponses metaboliques (glucose, acides gras non esterifies) et hormonales (insuline, catecholamines) lors d'un exercice sur ergocycle (30 minutes a 60 % de O2max) chez huit petites filles prepuberes (9,7±0,4 ans) et huit femmes adultes (21,5±0,9 ans). Methodes L'ingestion de glucose a lieu entre la 2e et la 3e minute de l'exercice. Des echantillons ont ete preleves sur sang veineux en position assise sur le cycloergometre ainsi qu'aux 3e, 5e, 10e, 15e et 30e minutes de l'exercice et apres 30 minutes de recuperation. Resultats Durant l'exercice, les concentrations plasmatiques de glucose etaient superieures chez la petite fille. Les valeurs absolues et l'evolution de l'insulinemie etaient strictement identiques dans les deux groupes. Les concentrations de noradrenaline durant l'exercice etaient semblables dans les deux groupes, alors que les concentrations d'adrenaline etaient inferieures chez l'enfant. Le rapport glucose/insuline, utilise comme indicateur de la sensibilite a l'insuline, etait toujours plus eleve chez la petite fille. Conclusion Nos resultats indiquent une plus faible tolerance au glucose durant l'exercice chez la petite fille prepubere. Une relative insulinoresistance, bien connue au repos en periode peripubertaire, est ici envisagee a l'exercice et pourrait engendrer une meilleure utilisation des graisses chez la petite fille, comme le suggerent les valeurs significativement plus elevees en acides gras non esterifies plasmatiques.

25 Patienten mit koronarer Herzerkrankung (KHK, 62 ± 9 Jahre) und 18 Herzgesunde (28 ± 6 Jahre) absolvierten je eine stufenformige fahrradergometrische Belastung in sitzender Position und eine Stresechokardiographie in halbliegender Linksseitenlage. Wahrend sich bei den Gesunden fur die Herzfrequenz, den Blutdruck und das Druck-Frequenz-Produkt keine wesentlichen Unterschiede zwischen den beiden Belastungsformen nachweisen liesen (2 × 3 ANOVA, t-Tests mit α-Adjustierung), zeigten die KHK-Patienten auf gleichen Belastungsstufen signifikant hohere Herzfrequenzen und ein signifikant hoheres Druck-Frequenz-Produkt (bei 50 W: 15 300 ± 2793 mmHg/min vs. 13 822 ± 3042 mmHg/min; bei 75 W. 18 028 ± 3479 mmHg/min vs. 16 337 ± 2619 mmHg/min) bei der Stresechokardiographie im Vergleich zur Fahrradergometrie in sitzender Position. Keine Unterschiede fanden sich in dieser Gruppe fur den systolischen Blutdruck; der diastolische Blutdruck war lediglich in Ruhe und bei der Eingangsstufe von 50 W im Sitzen hoher. Die Laktatkonzentrationen (nur bei den Gesunden gemessen) lagen auf allen Belastungsstufen der Stresechokardiographie signifikant hoher, die Leistung an der individuellen anaeroben Schwelle (IAS) war signifikant niedriger.

Three main sources of civilisation diseases like myocardial ischemic disorder or tumours are an insufficient physical activity, improper boarding customs and stress. A basic model of the life style intervention focuses on these areas. The psychic state control module uses a questionnaire that can show patient's predisposition to some kinds of diseases according to presence or absence of certain personality characteristics. The boarding control module determines patient's boarding customs by evaluating his or her personal diet and can recommend the composition of food for this patient. The physical activity control module controls the physical activity of patients by using a bicycle ergometer.

The purpose of this study was to estimate daily energy expenditure (EE) and daily activity factor (DAF: EE/basal metabolism - 1) of junior high school students in Japan using heart rate (HR) monitoring method. Daily activity recording and 24 hour HR monitoring were measured in all the subjects. The relational formulas between HR and oxygen consumption were obtained from bicycle ergometer test. Subjects were 112 junior high school students (68 male and 44 female) from the 1st to the 3rd year. The averages of EE (kcal/kg) of the 1st, 2nd, and 3rd year students were 54.3, 46.7, and 44.5 (kcal/kg) for males and 50.1, 44.4, and 40.5 (kcal/kg) for females respectively. In the same way DAF were 0.80, 0.61, and 0.59 for males and 0.77, 0.65, and 0.51 for females. It was shown that EE (kcal/kg) and DAF have a tendency to decrease as school year increases in both male and female students.

Twenty-five patients with clinically and histologically verified acute hepatitis were subjected to a submaximal bicycle ergometer exercise during the first week after inpatient admission and afterwards subdivided into two groups. The first group maintained bedrest, and the other group trained for 30 minutes a day over six weeks at an exercise level amounting to 70% of the submaximal performance of the initial ergometry. Histological, clinical and laboratory results did not differ between the groups. It is concluded that immobilization for a short time only is indicated in acute hepatitis.

The aim of this study was to compare optimal pedalling velocities during maximal (OVM) and submaximal (OVSM) cycling in human, subjects with different training backgrounds. A group of 22 subjects [6 explosive (EX), 6 endurance (EN) and 10 non-specialised subjects] sprint cycled on a friction-loaded ergometer four maximal sprints lasting 6 s each followed by five 3-min periods of steady-state cycling at 150 W with pedalling frequencies varying from 40 to 120 rpm. The OVM and OVSM were defined as the velocities corresponding to the maximal power production and the lowest oxygen consumption, respectively. A significant linear relationship (r2 = 0.52, P < 0.001) was found between individual OVM [mean 123.1 (SD 11.2) rpm] and OVSM [mean 57.0 (SD 4.9) rpm, P < 0.001] values, suggesting that the same functional properties of leg extensor muscles influence both OVM and OVSM. Since EX was greater than EN in both OVM and OVSM (134.3 compared to 110.9 rpm and 60.8 compared to 54.0 rpm, P < 0.01 and P < 0.05, respectively) it could be hypothesised that the distribution of muscle fibre type plays an important role in optimising both maximal and submaximal cycling performance.

Seven subjects exercised to exhaustion on a bicycle ergometer at a workload corresponding to an intensity of 70% maximal oxygen uptake (VO2max). On one occasion (FED), subjects consumed a preexercise carbohydrate (CHO) containing breakfast (100 g CHO) 3 h before exercise. On the other occasion (FASTED), subjects exercised after an overnight fast. Exercise time to fatigue was significantly longer (P0.05) when subjects consumed the breakfast (136+/-14 min) compared with when they exercised in the fasted state (109+/-12 min).Pre- and post-exercise muscle glycogen concentrations, respiratory exchange ratio, carbohydrate and fat oxidation, and lactate and insulin concentrations were not significantly different between the two trials. Insulin concentrations decreased significantly (P0.05) from 4.7+/-0.05 microIU.mL(-1) to 2.8+/-0.4 microIU.mL(-1) in FED and from 6.6+/-0.6 microIU.mL(-1) to 3.7+/-0.6 microIU.mL(-1) in FASTED subjects and free fatty acid concentrations (FFA) increased significantly (P0.05) from 0.09+/-0.02 mmol.L(-1) to 1.4+/-0.6 mmol.L(-1) in FED and from 0.17+/-0.02 mmol.L(-) to 0.74+/-0.27 mmol.L(-1) in FASTED subjects over the duration of the trials.In conclusion, the important finding of this study is the increased time to fatigue when subjects ingested the CHO meal with no negative effects ascribed to increased insulin concentrations and decreased FFA concentrations after CHO ingestion.

The significance of the time from anaerobic threshold to respiratory compensation point (RCP-AT time) in patients with chronic heart failure was investigated. Thirty-seven patients with chronic heart failure (New York Heart Association class II or III) were enrolled into the study. Cardiopulmonary exercise testing was performed using breath-by-breath gas sampling. A bicycle ergometer was used, and incremental exercise testing was carried out. Anaerobic threshold, respiratory compensation point (RCP), and the slope of oxygen uptake (VO2) as a function of work rate (deltaVO2/deltaWR) were measured. A positive correlation (r=0.53) between RCP-AT time and deltaVO2/deltaWR was found. RCP-AT time was corrected for the whole exercise period (ramp exercise-RCP point), and the correlation between corrected RCP-AT time and deltaVO2/deltaWR was still present (r=0.46). There was no correlation between RCP-AT time and anaerobic threshold. These findings suggest that RCP-AT time is a new parameter that reflects the rate of the aerobic and anaerobic metabolism after AT.

We investigated whether correction for body mass is appropriate when using variables derived from gas exchange measurements in the assessment of chronic heart failure. Patients with heart failure were studied either on a bicycle ergometer (22 subjects) or on a treadmill (28 subjects). For bicycle exercise testing either peak VO2 or peak VCO2 uncorrected for body mass reflected exercise capacity. However, for treadmill exercise, body mass correction was necessary to relate exercise capacity to peak VO2 or peak VCO2. Mass correction is therefore appropriate for treadmill but not for bicycle exercise.

The purpose of this study was to clarify the appropriate mode of exercise testing for detecting AT in patients with stroke. Forty subjects participated in this study. Bicycle ergometer, treadmill and one-leg exercise were used to detect AT. Each mode of exercise testing was conducted twice in every subject to investigate the test-retest reliability of AT. AT was determined by the V-slope method. Twenty-six of the subjects performed the test on a bicycle ergometer, 13 on a treadmill, and 17 underwent one-leg exercise. Test-retest reliability was assessed by intraclass correlation coefficient (ICC). Although ICC was good to excellent in all modes of exercise testing, the detection rate of AT was highest (92%) in exercise testing on a bicycle ergometer. This result suggested that the bicycle ergometer was the most appropriate mode of exercise testing for detecting AT in patients with stroke among the three modes used in this study.

The purpose of this study was to examine the influence of the type of exercise (running vs. cycling) on the O2uptake (V˙o 2) slow component. Ten triathletes performed exhaustive exercise on a treadmill and on a cycloergometer at a work rate corresponding to 90% of maximalV˙o 2 (90% work rate maximalV˙o 2). The duration of the tests before exhaustion was superimposable for both type of exercises (10 min 37 s ± 4 min 11 s vs. 10 min 54 s ± 4 min 47 s for running and cycling, respectively). TheV˙o 2 slow component (difference between V˙o 2 at the last minute and minute 3 of exercise) was significantly lower during running compared with cycling (20.9 ± 2 vs. 268.8 ± 24 ml/min). Consequently, there was no relationship between the magnitude of theV˙o 2 slow component and the time to fatigue. Finally, because blood lactate levels at the end of the tests were similar for both running (7.2 ± 1.9 mmol/l) and cycling (7.3 ± 2.4 mmol/l), there was a clear dissociation between blood lactate and the V˙o 2slow component during running. These data demonstrate that 1) theV˙o 2 slow component depends on the type of exercise in a group of triathletes and 2) the time to fatigue is independent of the magnitude of theV˙o 2 slow component and blood lactate concentration. It is speculated that the difference in muscular contraction regimen between running and cycling could account for the difference in theV˙o 2 slow component.

This investigation was conducted to study the effects on sprint performance of glucose and fructose ingestion during a 15-min rest period half way through 90 min of continuous and intermittent exercise. On three occasions, eight subjects cycled at 76 +/- 2% VO2max for 90 min (continuous trials: CON trials) with a 15-min half-time break.On another three occasions, they cycled for 90 min between moderate (65% VO2max) and high (100% VO2max) intensity (intermittent trials: INT trials) with the same half-time. In both trials, 90-min exercise was followed by a 40-s Wingate test to evaluate remaining sprint capacity. During half-time, they consumed either 20% glucose polymer (G), 20% fructose (F) or sweet placebo (P). Ingestion of G maintained plasma glucose levels, carbohydrate oxidation rate and lower value of ratings of perceived exertion (RPE) in both trials and indicated higher sprint performance compared with P (mean power of CON trials: 614.3 +/- 23.3 W vs 574.0 +/- 22.7 W, P0.001, INT trials: 629.5 +/- 27.6 W vs 596.3 +/- 25.5 W, P0.01).Ingestion of F showed similar effect in CON trials (603.8 +/- 26.1 W vs 574.0 +/- 22.7 W, P0.01) but had no positive effect in INT trials. Additionally, mean power of G was higher than F (629.5 +/- 27.6 W vs 598.4 +/- 34.2 W, P0.01) in INT trials.These results indicated that ingestion of G during half-time of 90-min exercise could maintain carbohydrate utilization and improve sprint performance in both CON and INT trials.

We evaluated the impact of diastolic function and gender on exercise capacity in sedentary, untreated hypertensive subjects (34 men, 23 women) using echocardiography and a bicycle ergometry with measurement of oxygen consumption (VO2). In men, peak (A) mitral inflow velocity and left ventricular (LV) mass were inversely related to peak VO2 (r = −0.64) and maximal workload (r = −0.57) and were the sole independent determinants of exercise capacity. In women, there was no relationship between any echocardiographic measure and exercise capacity. Thus, LV mass and Doppler-determined diastolic function predict maximal VO2 in hypertensive men but not in women. This finding may be related to gender differences in the contribution of diastolic filling to exercise capacity or may reflect limitations of resting Doppler echocardiography to predict exercise diastolic filling in hypertensive women.

Purpose To study a comparison of problems arising in pulmonary rehabilitation programs in North America, Europe, and Tokyo. Methods The survey instrument was a 13-item questionnaire sent in December 1994 to institutions in North America (n = 178), Europe (n = 179), and Tokyo (n = 399). Results Response rates were 51%, 40%, and 51% for North America, Europe, and Tokyo, respectively. Pulmonary rehabilitation programs were available at 56% of hospitals in North America and 74% in Europe, but at only 20% of hospitals in Tokyo. Most PRPs were conducted in an outpatient setting in North American (98%), whereas both outpatient (55%) and inpatient programs (65%) were adopted in Europe. Although the type of lung disease for which patients in both North America and Europe were referred to PRPs was mainly chronic obstructive pulmonary disease, this accounted for only 34% of referrals in Tokyo. However, referrals for primary tuberculosis sequelae (P = 0.028) and bronchiectasis (P = 0.021) were more common in Europe, similar to the situation in Tokyo. The following PRP items were available at significantly higher rates in North America than in Europe, and most were unavailable in Tokyo: family education, psychological support, nutritional instruction, treadmill, bicycle ergometer, walking training, and increasing the activity of daily living. Conclusion Pulmonary rehabilitation programs in North America are more multidimensional. However, target diseases differ among North America, Europe, and Tokyo. Pulmonary rehabilitation programs in Tokyo differed from those in North America and Europe and were poorly programmed. Problems arising in PRPs in the three regions include lack of staff and insufficient reimbursement.

To investigate the regulation of intramuscular fuel selection, we measured the malonyl-CoA (M-CoA) content in human skeletal muscle at three exercise power outputs [35, 65, and 90% maximal rate of O2consumption (V˙o2 max)]. Four males and four females cycled for 10 min at one power output on three separate occasions with muscle biopsies sampled at rest and at 1 and 10 min. The respiratory exchange ratio was 0.84 ± 0.03, 0.92 ± 0.02, and >1.0 at 35, 65 and 90%V˙o2 max, respectively. Muscle lactate content increased and phosphocreatine content decreased as a function of power output. Pyruvate dehydrogenase a activity increased from 0.40–0.64 mmol ⋅ kg wet muscle−1⋅ min−1at rest to 1.57 ± 0.28, 2.80 ± 0.41, and 3.28 ± 0.27 mmol ⋅ kg wet muscle−1⋅ min−1after 1 min of cycling at the three power outputs, respectively. Mean resting M-CoA contents were similar at all power outputs (1.85–1.98 μmol/kg dry muscle). During exercise at 35%V˙o2 max, M-CoA decreased from rest at 1 min (1.85 ± 0.29 to 1.20 ± 0.12 μmol/kg dry muscle) but returned to rest level by 10 min (1.86 ± 0.25 μmol/kg dry muscle). M-CoA content did not decrease during cycling at 65%V˙o2 max. At 90%V˙o2 max, M-CoA did not increase despite significant acetyl-CoA accumulation (the substrate for M-CoA synthesis). The data suggest that a decrease in M-CoA content is not required for the increase in free fatty acid uptake and oxidation that occurs during exercise at 35 and 65%V˙o2 max. Furthermore, M-CoA content does not increase during exercise at 90%V˙o2 maxand does not contribute to the lower rate of fat oxidation at this power output.

The aim of this study was to investigate the effect of different Recovery Duration (RD) between each sprint (30 s, 1 min, 3 min, 5 min, 10 min and 24 h) during the force-velocity test and to analyse associated anaerobic parameters such as maximal anaerobic power and blood lactate concentrations. Twelve male physical education students aged from 18 to 26 years took part in this study. Maximal anaerobic power (Pmax) was not statistically different whatever the recovery duration (from 885 to 938 watts, for RD 30 s to RD 24 h, respectively). This was associated with a tendency during the longer RD tests for optimal velocity to decrease (p = ns) while optimal force increased (p0.05). Blood lactate concentrations were regularly increased from 1.7 to a 9 mmol x l(-1) plateau at sprint 4 for RD tests10 min and were quite stable from the second sprint with an associated value from 2.2 to 4.7 mmol x l(-1) for RD 10 min and RD 24 h. In spite of statistically different values for [L]s between the tests, the power developed for each sprint remained unchanged. These data indicate that the attainment of maximal power seems independent from the recovery duration (10 s) and the pre-blood lactate values observed between each sprint during the force-velocity test. The way to reach Pmax was different between the tests. Different partition of energetic pathways are suggested. In conclusion, the force-velocity test could be performed with a shorter and the arbitrary five minutes recovery duration.

Dehydration and hyperthermia may impair gastric emptying (GE) during exercise; the effect of these alterations on intestinal water flux (WF) is unknown. Thus the purpose of this study was to determine the effect of hypohydration (∼2.7% body weight) on GE and WF of a water placebo (WP) during cycling exercise (85 min, 65% maximal oxygen uptake) in a cool environment (22°C) and to also compare GE and WF of three carbohydrate-electrolyte solutions (CES) while the subjects were hypohydrated. GE and WF were determined simultaneously by a nasogastric tube placed in the gastric antrum and via a multilumen tube that spanned the duodenum and the first 25 cm of jejunum. Hypohydration was attained 12–16 h before experiments by low-intensity exercise in a hot (45°C), humid (relative humidity 50%) environment. Seven healthy subjects (age 26.7 ± 1.7 yr, maximal oxygen uptake 55.9 ± 8.2 ml ⋅ kg−1⋅ min−1) ingested either WP or a 6% (330 mosmol), 8% (400 mosmol), or a 9% (590 mosmol) CES the morning following hypohydration. For comparison, subjects ingested WP after a euhydration protocol. Solutions (∼2.0 liters total) were ingested as a large bolus (4.6 ml/kg body wt) 5 min before exercise and as small serial feedings (2.3 ml/kg body wt) every 10 min of exercise. Average GE rates were not different among conditions ( P > 0.05). Mean (±SE) values for WF were also similar ( P > 0.05) for the euhydration (15.3 ± 1.7 ml ⋅ cm−1⋅ h−1) and hypohydration (18.3 ± 2.6 ml ⋅ cm−1⋅ h−1) experiments. During exercise after hypohydration, water absorption was greater ( P < 0.05) with ingestion of WP (18.3 ± 2.6) and the 6% CES (16.5 ± 3.7), compared with the 8% CES (6.9 ± 1.5) and the 9% CES (1.8 ± 1.7). Mean values for final core temperature (38.6 ± 0.1°C), heart rate (152 ± 1 beats/min), and change in plasma volume (−5.7 ± 0.7%) were similar among experimental trials. We conclude that 1) hypohydration to ∼3% body weight does not impair GE or fluid absorption during moderate exercise when ingesting WP, and 2) hyperosmolality (>400 mosmol) reduced WF in the proximal intestine.

We evaluated the effect of endurance training (cycling 3 times per week for 12 weeks) on succinate dehydrogenase (SDH) activity in the subsarcolemmal (SS) and intermyofibrillar (IMF) regions of vastus lateralis muscle fibres in 7 individuals (4 females and 3 males). SDH activity of the SS region increased 9.4% and 12.8% in type I and II fibres, respectively (p

The goal of diagnostic testing is to maximize information (I) of a specific disease of interest (D) resulting from the performance of a specific diagnostic test procedure (T). However, all tests suffer from errors which result in incomplete information and inaccurate diagnostic conclusions. The methods of Information Theory have successfully solved a range of signal transmission problems involving physical systems operating under conditions of noise. Medical testing procedures were found to be analogous to noisy systemss hence, Information Theory methods were applied to minimize errors in diagnostic testing. Prior to performing a diagnostic test, the quantity of information, Apriori Information (ID), regarding the presence or absence of the disease was only a function of the prevalence (P) of disease in the population. After performing a diagnostic test, the quantity of information, Aposteriori Information (IDIT) was a function of not only P but also the test sensitivity (A) and test specificity (B). The quantity of information gained by test performance was computed from the difference between aposteriori and apriori information. \Delta {\rm I}={\rm I_{\rm DIT}-I_D} To illustrate the relationship between pretest, apriori, and post-test, aposteriori, information the values ID and IDIT were computed for five common cardiovascular tests applied to populations with different coronary artery disease prevalence. This cross-sectional analysis studied the quantitative information obtained from Electrocardiography (ECG), Bicycle Ergometer Stress Tests (BEST), Stress-Echo Ergometer Tests (SEET), Thallium 201 Stress Tests (ThST), and Coronary Arteriography (CorA). Apriori information ranged from a minimum of 0 (for prevalence e 0.5) to a maximum of 1.0 (for prevalence e 0 or 1.0) The aposteriori information was computed for all apriori information and occupied the range between that of a “perfect” test (A e 1.0 and B e 1.0) and that of a “worthless” test (A e 0.5 and B e 0.5). All tests demonstrated greater information gain when apriori information was minimals Little additional information could be gained when the apriori information was close to certainty (i.e., for prevalence near 0 or 1.0). Electrocardiography demonstrated little significant IDIT at any value of ID. Thallium 201 stress tests provided similar aposteriori information values to those of Stress-Echo Ergometer Stress and either demonstrated greater information gain than Bicycle Ergometer Stress Tests. Coronary Arteriography provided the maximum values of aposteriori information. Information Theory methods provided an effective quantitative method to compare the effectiveness of diagnostic tests over a wide range of disease prevalence.

A number of studies have demonstrated considerable plasma volume changes during and after exposure to different environmental and physiological conditions. These changes are thought to result from transient fluid shifts into (haemodilution) and out of (haemoconcentration) the intravascular space. If the levels of plasma constituents are to be routinely measured for research purposes or used as indicators of training adaptation or the health of an athlete, then it is important to consider the dynamic nature of plasma volume. Controversy still exists over the relevance of plasma volume interactions with plasma constituent levels, and while some investigators have taken plasma volume shifts into account, others have chosen to ignore these changes. Bouts of acute exercise have been shown to produce a transient haemoconcentration immediately after long distance running, bicycle ergometry and both maximal and submaximal swimming exercise. While these changes are transient, lasting only a few hours, other studies have reported a longer term haemodilution following acute exercise. In addition, endurance training has been shown to cause long term expansion of the plasma volume. It would, therefore, seem important to consider the influence of plasma volume changes on plasma solutes routinely measured for research, and as markers of training adaptation, prior to arriving at conclusions and recommendations based purely on their measured plasma level. To further confound this issue, plasma volume changes are known to be associated with heat acclimatisation, hydration state, physical training and postural changes, all of which may differ from one experiment or exercise bout to the next, and should thus be taken into account.

Schmidt, W., A. Bub, M. Meyer, T. Weiss, D. Schneider, N. Maassen, and W. G. Forssmann. Is urodilatin the missing link in exercise-dependent renal sodium retention? J. Appl. Physiol. 84(1): 123–128, 1998.—The purpose of the present study was to investigate the behavior of plasma atrial natriuretic peptide [ANP-(99—126)] concentration ([ANP]) and renal urodilatin [Uro; ANP-(95—126)] excretion during and after exercise and their possible effects on renal Na+retention. Ten male subjects performed a cycle ergometer test for 60 min at 60% of maximum workload. Blood and urine samples were collected before, during, and up to 24 h after exercise. During exercise, plasma [ANP] and renal Uro excretion were oppositely affected: whereas [ANP] increased from 46.5 ± 5.1 to 124.1 ± 10.6 pg/ml, urinary Uro excretion decreased from 120.8 ± 16.0 to 49.5 ± 9.8 fmol/min and remained at a lower level until 1 h after exercise. Glomerular filtration rate showed lowest values during exercise (from 164.9 ± 15.3 to 75.8 ± 10.1 ml/min), and urine flow and the fractional excretion rate of Na+([Formula: see text]) and Cl−([Formula: see text]) had their nadir during the first hour after exercise. Positive relationships were observed between Uro excretion and[Formula: see text]( P < 0.05) and[Formula: see text], whereas a tendency toward a negative correlation was obtained between [ANP] and[Formula: see text]. It seems possible that Uro may be, among other factors, involved in the exercise-related regulation of renal Na+retention. The specific roles Uro and ANP play during exercise, however, remain to be investigated.