Arie Rotstein

Normal cardiopulmonary responses during incremental exercise in 20- to 70-yr-old men.

Healthy men (N = 1424, age 20-70 yr) underwent a progressive incremental treadmill exercise test to volitional maximum. Cardiopulmonary variables were measured breath-by-breath. The aerobic power (VO2max) declined at an average yearly rate of 0.33 ml.kg.-1min-1, HRmax declined 0.685 beats.min-1.yr-1, and max O2 pulse declined at an annual rate of 0.115 ml.beat-1.kg-1*100. Gas exchange threshold (GET) expressed as percentage of VO2max was 58% and 69% in the youngest (20-30 yr) and oldest (61-70 yr) decades, respectively. The average decline in VE, Vt, f, and PETCO2 over the entire age range was 29%, 10%, 21%, and 7%, respectively. There were increases in VE/VO2, and VE/VECO2, from age 20-70 yr of 13% and 14%, respectively, but no changes across 5 decades in PETO2. Physical (height and weight) as well as life-style characteristics (leisure time activity, place of residency, smoking), were found to be potent predictors in most of the cardiopulmonary values at maximal exercise and therefore should be incorporated in the predictive equations for such variables. Normal response patterns of most cardiopulmonary variables throughout the range of exercise intensities were shown to be age-affected and thus should be standardized for age decades.

Specific inspiratory muscle training in well-trained endurance athletes

PURPOSE It has been reported that arterial O2 desaturation occurs during maximal aerobic exercise in elite endurance athletes and that it might be associated with respiratory muscle fatigue and relative hypoventilation. We hypothesized that specific inspiratory muscle training (SIMT) will result in improvement in respiratory muscle function and thereupon in aerobic capacity in well-trained endurance athletes. METHODS Twenty well-trained endurance athletes volunteered to the study and were randomized into two groups: 10 athletes comprised the training group and received SIMT, and 10 athletes were assigned to a control group and received sham training. Inspiratory training was performed using a threshold inspiratory muscle trainer, for 0.5 h x d(-1) six times a week for 10 wk. Subjects in the control group received sham training with the same device, but with no resistance. RESULTS Inspiratory muscle strength (PImax) increased significantly from 142.2 +/- 24.8 to 177.2 +/- 32.9 cm H2O (P < 0.005) in the training but remained unchanged in the control group. Inspiratory muscle endurance (PmPeak) also increased significantly, from 121.6 +/- 13.7 to 154.4 +/- 22.1 cm H2O (P < 0.005), in the training group, but not in the control group. The improvement in the inspiratory muscle performance in the training group was not associated with improvement in peak VEmax, VO2max breathing reserve (BR). or arterial O2 saturation (%SaO2), measured during or at the peak of the exercise test. CONCLUSIONS It may be concluded that 10 wk of SIMT can increase the inspiratory muscle performance in well-trained athletes. However, this increase was not associated with improvement in aerobic capacity, as determined by VO2max, or in arterial O2 desaturation during maximal graded exercise challenge. The significance of such results is uncertain and further studies are needed to elucidate the role of respiratory muscle training in the improvement of aerobic-type exercise capacity.

Physiological responses to incremental exercise in patients with chronic fatigue syndrome.

PURPOSE The purpose of this investigation was to characterize the physiological response profiles of patients with chronic fatigue syndrome (CFS), to an incremental exercise test, performed to the limit of tolerance. METHODS Fifteen patients (12 women and three men) who fulfilled the case definition for chronic fatigue syndrome, and 15 healthy, sedentary, age- and sex-matched controls, performed an incremental progressive all-out treadmill test (cardiopulmonary exercise test). RESULTS As a group, the CFS patients demonstrated significantly lower cardiovascular as well as ventilatory values at peak exercise, compared with the control group. At similar relative submaximal exercise levels (% peak VO(2)), the CFS patients portrayed response patterns (trending phenomenon) characterized, in most parameters, by similar intercepts, but either lower (VCO(2), HR, O(2pulse), V(E), V(T), PETCO(2)) or higher (B(f), V(E)/VCO(2)) trending kinetics in the CFS compared with the control group. It was found that the primary exercise-related physiological difference between the CFS and the control group was their significantly lower heart rate at any equal relative and at maximal work level. Assuming maximal effort by all (indicated by RER, PETCO(2), and subjective exhaustion), these results could indicate either cardiac or peripheral insufficiency embedded in the pathology of CFS patients. CONCLUSION We conclude that indexes from cardiopulmonary exercise testing may be used as objective discriminatory indicators for evaluation of patients complaining of chronic fatigue syndrome.

The effects of alkaline treatment on short‐term maximal exercise

Abstract The effects of alkalosis on submaximal and maximal exercise performance of a relatively long duration have been investigated previously. The present study examined the effects of sodium bicarbonate ingestion on cycling performance of the 30 s Wingate Anaerobic Test using 13 male physical education students. Three hours prior to exercise, subjects ingested either table salt (control) or sodium bicarbonate (alkalosis) of equimolar dosage (10 and 13 g, respectively) in capsule form. Biopsies were taken from the m. vastus lateralis for determination of muscle fibre composition. Resting blood pH was 7.43±0.01 (mean±s.e.) for the alkaline condition versus 7.37 + 0.01 for the control condition (P < 0.01). Mean power output increased significantly (P<0.05) following alkaline treatment. Peak power output was not affected. No relationship was found between fibre type distribution and sensitivity to the alkaline treatment. The increased alkali reserve reduced mean post‐exercise acidosis by 0.05 pH units (P<...

Estimation of %VO2 reserve from heart rate during arm exercise and running.

Abstract The purpose of the present investigation was to examine the relationship between the percent heart rate reserve (%HRR) in arm exercise and the corresponding percent oxygen uptake (V˙O2) reserve, and to compare this relationship to that occurring in running. Fourteen male physical education students took part in the study. Each subject performed a maximal running exercise test and a maximal arm cycling test. The subjects also performed three submaximal exercise bouts (in both exercise modes) at 30%, 60% and 80% of their HRR. The subjects were monitored for their heart rate (HR) at rest, maximal HR (HRmax), HR at submaximal work loads, maximal V˙O2 (V˙O2max), V˙O2 at rest and V˙O2 at submaximal loads. For each subject, load and exercise mode, %HRR and %V˙O2 reserve were calculated (from HRmax and V˙O2max as measured during running and arm cycling) and the relationship between the two was evaluated. The main finding of the present investigation is that the prediction of %V˙O2 reserve in arm cycling from %HRR is grossly overestimated when calculated from HRmax and V˙O2max measured during running. The prediction is better but still overestimated when calculated from HRmax and V˙O2max measured during arm cycling. The findings indicate a better prediction of %V˙O2 reserve from %HRR for running than for arm exercise. These findings should be taken into consideration when prescribing the target HR for arm training.

Left ventricular responses during prolonged treadmill walking with heavy load carriage

This study examined with metabolic cart and echo-Doppler the influence of different load carriage during 4 h of treadmill walking on left ventricular systolic function, hemodynamics, and cardiovascular responses. Twenty-six aerobically well-trained male subjects (VO2max = 65.2 +/- 5 ml.kg-1.min-1) volunteered for this study. Subjects carried a load of 38 kg during one session and a load of 50 kg during the other session. Following the 4-h exercise in each session, significant (P < 0.05) differences were noted between the 38-kg and 50-kg workloads with regard to VO2: 14.4 +/- 2 and 19 +/- 5 ml.kg-1.min-1; heart rate: 104 +/- 14 and 125 +/- 17 beats.min-1; diastolic blood pressure: 69 +/- 4 and 79 +/- 4 mm Hg; and rate pressure product 140.4 +/- 15 and 173.8 +/- 20 index.10(-2), respectively. No significant differences were noted between the workloads in regard to systolic blood pressure, perceived exertion rating, and aortic valve Doppler indices. We concluded that during prolonged treadmill walking in well-trained young subjects, the additional load above 50% up to 66% of body weight did not change the steady state of left ventricular systolic function, hemodynamics, and cardiovascular responses throughout the course of the 240 min of effort.

Relationships of marathon running to physiological, anthropometric and training indices

SummaryThis study was aimed at investigating the relationships between marathon performance time (MPT) and a set of variables wider in scope than that used to date in similar studies. Sixteen marathon runners of varying abilities were examined for the following variables prior to the start of a marathon race: age, weight (wt); height (ht); triceps, abdominal and subscapular (SSF) skinfolds; % fat; rectal temperature; average weekly training distance over the preceding 2–3 months and over the preceding year (ATD); hematocrit; creatine phosphokinase (CPK); aldosterone and cortisol. MPTs ranged between 2; 15:21 and 4; 54:31 h. The coefficients of the simple linear correlations with MPT were: age, 0.70; wt·ht−2, 0.57; SSF, 0.67; % fat, 0.61; ATD, −0,64; CPK, 0.52 and cortisol, −0.41. In order of relative strength, CPK, age, ATD, SSF and cortisol were found by a multiple linear regression analysis to be the best predictors of MPT (R=0.99; p<0.0001) — explaning 98% of its observed variance. The diversified approach may be supported by the high R value obtained. However, the significance of additional factors in determining MPT is expected and cannot be excluded.

Perceived speech difficulty during exercise and its relation to exercise intensity and physiological responses

AbstractThe aim of this study was to establish how ratings of perceived speech production difficulty (PSPD) during exercise of varying intensities are correlated with various physiological responses, in order to determine whether the PSPD is suitable for prescribing exercise training intensity. An incremental running test was performed to establish the subjects’ maximal oxygen consumption (V̇O2max) and ventilatory anaerobic threshold (VAT). During the test, the subjects were asked to read a written text. The subjects graded their PSPD at each stage of the test using a 13-level PSPD scale. Throughout the test, various cardiopulmonary parameters were measured breath-by-breath. Regressions of V̇O2, heart rate (HR), and pulmonary ventilation (V̇E), all as percentages of their respective measured maximal values, plotted as a function of PSPD showed that the overall associations among those variables are strong and statistically significant (P<0.05). However, the individual variability within each relative V̇O2, V̇E or HR was found to be rather large. The subjects’ distribution in relation to their PSPD at the VAT scattered widely across the PSPD scale. These results indicate that estimating exercise intensity by measuring speech difficulty is not valid. Thus it may be assumed that the “talk test”, in its present non-standardized form, is a questionable substitute for the anaerobic threshold, HR, or for any other objective physiological measure for prescribing individual training exercise intensity.

Physiological Characteristics of the Preferred Transition Speed in Racewalkers

PURPOSE The preferred transition speed (PTS) at which humans change their gait from walking to running was found to be lower than their energetically optimal transition speed (EOTS). This phenomenon has not been examined in racewalkers. The purpose of this study was to evaluate the PTS and the EOTS in racewalkers compared with controls. METHODS Eleven racewalkers and 13 control subjects participated in this study. Subjects arrived at the laboratory on three occasions. Visit I: determination of PTS. Subjects walked at a slow speed that was increased by 0.2 km x h every 30 s until they felt it was easier to run. Then, subjects ran at a high speed and the treadmill speed was reduced by 0.2 km x h every 30 s until they felt it was easier to walk. Visits II and III: subjects walked and ran at PTS - 1 km x h, PTS - 0.5 km x h, PTS, PTS + 0.5 km x h, and PTS + 1 km x h. At each stage, physiological measurements were recorded. RESULTS PTS was 7.33 +/- 0.33 km x h in controls and 8.20 +/- 0.54 km.h in racewalkers (P < 0.001), and EOTS was 8.00 +/- 0.48 km x h in controls and 8.46 +/- 0.55 km x h in racewalkers (P = 0.039). There was a trend for a smaller difference between PTS and EOTS in racewalkers. V O2 was higher during running at the PTS in both groups (F1, 22 = 5.972, P = 0.023), and there was a trend for a group interaction (F1, 22 = 3.442, P = 0.077). HR and V E were higher at the PTS in racewalkers compared with controls. CONCLUSION Racewalkers have a higher PTS and EOTS compared with controls. There is a trend for the difference between the PTS and the EOTS to be smaller in racewalkers compared with controls.

The effects of negative air ions on various physiological functions during work in a hot environment

The effects of negative air-ions on human physical performance has been investigated. Twenty-one healthy males, 20–25 years old (X=23.6±2.6) were exposed to two 180-min rest and exercise sessions two weeks apart. The subjects were randomly assigned into either an experimental group (n=12) or to a control group (n=9). The experimental group performed the first session in neutral air conditions and the second one in air containing 1.36 to 1.90×105 negative air ions and 1.40 to 1.66×102 positive air ions/ml. The control group performed both sessions under neutral air conditions. All sessions were held at Ta=40±1‡C and 25±5% RH. Each session included one hour of resting under the respective ionization conditions, followed by 3 30-min cycle ergometer work bouts, separated by 7-min rest periods. The mechanical work-load during the bicycle exercise was 1.64±0.6 W/kg BW. The experimental group showed a significant reduction with negative air-ions in heart rate (HR), in rectal temperature, and in the rating of perceived exertion (RPE), all when compared with their own neutral session. The control group showed no significant changes between the first and the second exposure. Although not statistically significant, being exposed to negative air-ions seems also to reduce total sweat rate and minute ventilation (VE), and to increase O2 pulse. It is suggested that under the conditions of this study negative air ions canimprove various cardiovascular and thermoregulatory functions as well as subjective feelings during physical effort. It is felt that such positive influences may be augmented by increasing the exposure time to negative ionized air and/or prolonging the stressful conditions.