A double-blind, randomized, placebo-controlled trial on the effect of Ashwagandha (Withania somnifera dunal.) root extract in improving cardiorespiratory endurance and recovery in healthy athletic adults.

ETHNOPHARMACOLOGICAL RELEVANCE: Ashwagandha is a reputed herb in traditional Ayurveda, used for various ailments and improving general well-being. Improved cardiorespiratory endurance can aid in attaining better physiological, metabolic, and functional abilities in humans. According to Ayurveda, Ashwagandha has such potential to improve human health. AIM OF THE STUDY: This study aimed to evaluate the efficacy and safety of Ashwagandha root extract in enhancing cardiorespiratory endurance in healthy athletic adults. MATERIALS AND METHODS: Fifty healthy athletic adults were selected randomly and equally allocated to Ashwagandha and placebo groups. The Ashwagandha group received 300 mg of Ashwagandha root extract capsules, twice daily, for 8-weeks. Cardiorespiratory endurance was assessed by measuring the maximum aerobic capacity (VO2 max). Estimation of stress management was done through Total Quality Recovery Scores (TQR), Recovery-Stress Questionnaire for Athletes (RESTQ), and Daily Analysis of Life Demands for Athletes (DALDA) questionnaires along with the antioxidant level measurement. RESULTS: At the end of the study, a statistically significant improvement in VO2 max outcome was observed in the Ashwagandha group when compared to the placebo group (P = 0.0074). The subjects in the Ashwagandha group also displayed a statistically significant increase at the end of the study when compared to the baseline (P < 0.0001). Significantly improved TQR scores were observed in the Ashwagandha group members compared to their placebo counterparts (P < 0.0001). DALDA questionnaire analysis in the Ashwagandha group was found statistically significant (P < 0.0001) compared to the placebo group. RESTQ assessment also yielded better outcomes, especially for fatigue recovery (P < 0.0001), lack of energy (P < 0.0001), and fitness analysis (P < 0.0001). The enhanced antioxidant level was significant (P < 0.0001) in the Ashwagandha group. CONCLUSION: The present findings suggest that Ashwagandha root extract can successfully enhance cardiorespiratory endurance and improve the quality of life in healthy athletic adults. No adverse events were reported by any of the subjects in this study.

Efficacy of Shenling Baizhu San on stable chronic obstructive pulmonary disease patients: A systematic review and meta-analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Shenling Baizhu San (SBS) as a classic Chinese medicine prescription, has been extensively used in gastrointestinal diseases, such as ulcerative colitis and chronic diarrhea. In recent years, SBS has shown a beneficial effect on chronic obstructive pulmonary disease (COPD) patients. However, clinical trials had shown conflicting results of SBS on improving pulmonary function and other related indicators of patients with stable COPD. The efficacy of SBS on stable COPD patients has not been fully assessed. AIM OF THE STUDY: To determine whether the SBS used in the treatment of gastrointestinal disease was effective to treat COPD, we assessed the clinical evidence and efficacy of SBS supplemental treatment on stable COPD patients by a systematic review and meta-analysis of clinical trials. MATERIALS AND METHODS: Nine electronic databases were searched to include clinical trials (published until August 31, 2020) with SBS as a supplementation treatment on stable COPD. Mean difference (MD) was used to evaluate continuous variables, odds ratio (OR) was calculated to evaluate dichotomous. The Egger's test was applied for publication bias. RESULTS: A total of 770 COPD participants from 11 trials that met the inclusion criteria were included. The meta-analysis showed that modified SBS could improve the exercise endurance, life quality scores of stable COPD patients, and also showed the potential benefits to pulmonary function of COPD patients than original SBS. CONCLUSION: The methodological quality of included trials may limit the conclusions that indicate that modified SBS may have a promising treatment for improving FEV1/FVC and MVV, increasing exercise endurance and life quality scores on stable COPD patients.

Influence of sex, menstrual cycle, and oral contraceptives on the cerebrovascular response to paced deep breathing.

PURPOSE: Deep breathing assesses autonomic function; however, many researchers/clinicians do not account for hyperventilation, brain blood flow or blood pressure. METHODS: Men and women (with/without oral contraceptives) participated. women participated during low and high hormone phases of the menstrual cycle. Blood pressure, end-tidal carbon dioxide, middle cerebral artery velocity and cerebrovascular resistance were assessed. RESULTS: Deep breathing decreased end-tidal carbon dioxide and middle cerebral artery velocity while increasing cerebrovascular resistance in all participants; blood pressure decreased in men. There were no influences of menstrual cycle or oral contraceptives. CONCLUSIONS: Men have different autonomic responses to deep breathing compared to women.

Enhanced recovery of breathing capacity from combined adenosine 2A receptor inhibition and daily acute intermittent hypoxia after chronic cervical spinal injury.

Daily acute intermittent hypoxia (dAIH) improves breathing capacity after C2 spinal hemisection (C2HS) in rats. Since C2HS disrupts spinal serotonergic innervation below the injury, adenosine-dependent mechanisms underlie dAIH-induced functional recovery 2weeks post-injury. We hypothesized that dAIH-induced functional recovery converts from an adenosine-dependent to a serotonin-dependent, adenosine-constrained mechanism with chronic injury. Eight weeks post-C2HS, rats began dAIH (10, 5-min episodes, 10.5% O2; 5-min intervals; 7days) followed by AIH 3× per week (3×wAIH) for 8 additional weeks with/without systemic A2A receptor inhibition (KW6002) on each AIH exposure day. Tidal volume (VT) and bilateral diaphragm (Dia) and T2 external intercostal motor activity were assessed in unanesthetized rats breathing air and during maximum chemoreflex stimulation (MCS: 7% CO2, 10.5% O2). Nine weeks post-C2HS, dAIH increased VT versus time controls (p<0.05), an effect enhanced by KW6002 (p<0.05). dAIH increased bilateral Dia activity (p<0.05), and KW6002 enhanced this effect in contralateral (p<0.05) and ipsilateral Dia activity (p<0.001), but not T2 inspiratory activity. Functional benefits of combined AIH plus systemic A2A receptor inhibition were maintained for 4weeks. Thus, in rats with chronic injuries: 1) dAIH improves VT and bilateral diaphragm activity; 2) VT recovery is enhanced by A2A receptor inhibition; and 3) functional recovery with A2A receptor inhibition and AIH "reminders" last 4weeks. Combined dAIH and A2A receptor inhibition may be a simple, safe, and effective strategy to accelerate/enhance functional recovery of breathing capacity in patients with respiratory impairment from chronic spinal injury.

Pulmonary Functions, Oxidative Stress and DNA Damage in Workers of a Copper Processing Industry.

BACKGROUND: Occupational exposure to excessive level of copper results in many adverse health effects. OBJECTIVE: To measure pulmonary function, oxidative stress, and extent of DNA damage in workers of a copper processing industry. METHODS: 30 men working in a copper processing industry and 30 men matched for age and socioeconomic status (comparison group) were included in this study. Pulmonary function test parameters were measured for all participants. Serum malondialdehyde (MDA), ferric reducing ability of plasma (FRAP), glutathione (GSH) content in RBCs and 8-OHdG were assayed by ELISA. Extent of DNA damage in leucocytes was assayed by comet assay. RESULTS: Pulmonary function parameters, FVC, FEV1, PEFR, and MVV measured in workers were significantly (p<0.05) lower than those observed in the comparison group. Compared to the comparison group, MDA was significantly (p=0.002) increased in studied workers; TAOC (p=0.017), and GSH (p=0.020) were significantly lower in workers than the comparison group. There was significant DNA damage in leucocytes in workers compared to the comparison group (difference in olive tail moment p<0.001). PEFR, FEF25-75%, and MEF50% were negatively correlated with MDA. CONCLUSION: The observed DNA damage would be due to increased oxidative stress resulting from excessive exposure to copper.

PPARgamma agonist pioglitazone does not enhance performance in mice.

Peroxisome-proliferator-activated receptor (PPAR) delta and adenosine monophosphate (AMP)-activated protein kinases (AMPKs) regulate the metabolic and contractile characteristics of myofibres. PPAR proteins are nuclear receptors that function as transcription factors and regulate the expression of multiple genes. AMPK has been described as a master metabolic regulator which also controls gene expression through the direct phosphorylation of some nuclear proteins. Since it was discovered that both PPARdelta agonists (GW1516) and AMPK activators (5-aminoimidazole-4-carboxamide-1-ß-D-ribofuranoside, known as AICAR) are very effective performance-enhancing substances in sedentary mice, the World Anti-doping Agency (WADA) included AICAR and GW1516 in the prohibited list of substances as metabolic modulators in the class 'Hormone and metabolic modulators'. Thiazolidinediones are PPARgamma agonists that can induce similar biological effects to those of PPARdelta and PPARdelta-AMPK agonists. Thus in this study, the effects of pioglitazone on mitochondrial biogenesis and performance were evaluated. Blood glucose levels and the protein expression of the intermediates involved in the mitochondrial biogenesis pathway and the citrate synthase activity were determined in both gastrocnemius and soleus muscles. Maximal aerobic velocity (MAV), endurance capacity, and grip strength before and after the training period were also determined. The MAV endurance capacity and grip strength of trained animals significantly increased. We found that the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and the nuclear respiratory factor-1 (NRF-1) protein content and citrate synthase activity significantly increased in the soleus muscle of trained animals. No effect of treatment was found. Therefore in our study, pioglitazone administration did not affect mitochondrial biogenesis signaling pathway.

[Autonomic regulation at emotional stress under hypoxic conditions in the elderly with physiological and accelerated aging: effect of hypoxic training].

The effect of hypoxic training on autonomic regulation in psycho-emotional stress conditions in hypoxic conditions in older people with physiological (25 people) and accelerated (28 people) aging respiratory system. It is shown that hypoxic training leads to an increase in vagal activity indicators (HF) and reduced simpatovagal index (LF/HF), have a normalizing effect on the autonomic balance during stress loads in older people with different types of aging respiratory system.

No adverse effects of statins on muscle function and health-related parameters in the elderly: an exercise study.

The aim of the present study was to investigate the effects of a repeated bout of eccentric exercise on health-related parameters and muscle performance on subjects undergoing atorvastatin therapy. Twenty-eight elderly men participated in the investigation and were assigned either in a control (n = 14) or in a statin therapy group (n = 14). All participants performed two isokinetic eccentric exercise bouts separated by 3 weeks. Muscle damage indices, resting energy expenditure, substrate metabolism, lipid and lipoprotein profile, as well as insulin sensitivity, were evaluated before and after eccentric. No differences in muscle function were observed between the two groups either at rest or after exercise. Eccentric exercise increased resting energy expenditure, increased fat oxidation, improved lipid profile, and increased insulin resistance 2 days after both eccentric exercise bouts. However, these changes appeared to lesser extent after the second bout. No differences were observed in the responses in the health-related parameters in the control and in the statin therapy group. Eccentric exercise affected similarly the control and the atorvastatin-treated individuals. The present results indicate that atorvastatin-treated elderly individuals may participate in various physical activities, even high-intensity muscle-damaging activities, without negative impact on muscle function and adaptation.

Epigallocatechin-3-gallate increases maximal oxygen uptake in adult humans.

UNLABELLED: Epigallocatechin-3-gallate (EGCG), a component of green tea, increases endurance performance in animals and promotes fat oxidation during cycle ergometer exercise in adult humans. PURPOSE: We have investigated the hypothesis that short-term consumption of EGCG delays the onset of the ventilatory threshold (VT) and increases maximal oxygen uptake (VO2max). METHODS: In this randomized, repeated-measures, double-blind study, 19 healthy adults (11 males and 8 females, age = 26 ± 2 yr (mean ± SE)) received seven placebo or seven EGCG (135-mg) pills. Forty-eight hours before data collection, participants began consuming three pills per day; the last pill was taken 2 h before exercise testing. VT and VO2max were determined from breath-by-breath indirect calorimetry data collected during continuous incremental stationary cycle ergometer exercise (20-35 W·min(-1)), from rest until volitional fatigue. Each condition/exercise test was separated by a minimum of 14 d. RESULTS: Compared with placebo, short-term EGCG consumption increased VO2max (3.123 ± 0.187 vs 3.259 ± 0.196 L·min(-1), P = 0.04). Maximal work rate (301 ± 15 vs 301 ± 16 W, P = 0.98), maximal RER (1.21 ± 0.01 vs 1.22 ± 0.02, P = 0.27), and maximal HR were unaffected (180 ± 3 vs 180 ± 3 beats·min(-1), P = 0.87). In a subset of subjects (n = 11), maximal cardiac output (determined via open-circuit acetylene breathing) was also unaffected by EGCG (29.6 ± 2.2 vs 30.2 ± 1.4 L·min(-1), P = 0.70). Contrary to our hypothesis, EGCG decreased VO2 at VT (1.57 ± 0.11 vs 1.48 ± 0.10 L·min(-1)), but this change was not significant (P = 0.06). CONCLUSIONS: Short-term consumption of EGCG increased VO2max without affecting maximal cardiac output, suggesting that EGCG may increase arterial-venous oxygen difference.

Sildenafil improves the alveolar-capillary function in heart failure patients.

BACKGROUND: Sildenafil is used for pulmonary hypertension treatment and its use is safe in chronic heart failure (HF) patients. AIMS: To analyze the effects of sildenafil on lung mechanics, gas diffusion, exhaled nitric oxide (eNO) at rest and during exercise in chronic HF. We did so to evaluate if sildenafil prevents exercise-induced pulmonary edema formation. METHODS: We studied 22 chronic HF males. We measured after a single dose of placebo, sildenafil (25 mg) and sildenafil (100 mg), lung diffusion (DLCO), molecular diffusion (DM), pulmonary capillary volume (VC), eNO, all at rest and during exercise, standard pulmonary function, and maximal cardiopulmonary exercise. RESULTS: At rest sildenafil improved pulmonary mechanics and DLCO from 23.1+/-6.3 ml/mmHg/min to 23.9+/-6.4 (25 mg, p<0.05) and to 25.3+/-6.7 100 mg, p<0.02). Sildenafil (100 mg) prevents edema formation (highest DM/VC during exercise). At rest eNO was low and not affected by tested drugs. With light exercise eNO was higher with sildenafil 100 mg. Peak VO(2) increased with sildenafil from 1376+/-331 ml/min to 1471+/-375 (25 mg, p<0.01) and 1524+/-461 (100 mg, p<0.02). Peak VO(2) increase was related to DLCO improvement. CONCLUSION: In chronic HF sildenafil increases exercise performance, improves lung mechanics and gas diffusion and prevents exercise-induced pulmonary edema formation probably by restoring NO pathways.

Impact of acute exposure to air pollution on the cardiorespiratory performance of military firemen.

The objective of the present study was to determine the impact of acute short-term exposure to air pollution on the cardiorespiratory performance of military firemen living and working in the city of Guarujá, São Paulo, Brazil. Twenty-five healthy non-smoking firemen aged 24 to 45 years had about 1 h of exposure to low and high levels of air pollution. The tests consisted of two phases: phase A, in Bertioga, a town with low levels of air pollution, and phase B, in Cubatão, a polluted town, with a 7-day interval between phases. The volunteers remained in the cities (Bertioga/Cubatão) only for the time required to perform the tests. Cumulative load 10 +/- 2 min-long exertion tests were performed on a treadmill, consisting of a 2-min stage at a load of 7 km/h, followed by increasing exertion of 1 km h-1 min-1 until the maximum individual limit. There were statistically significant differences (P < 0.05) in anaerobic threshold (AT) between Cubatão (35.04 +/- 4.91 mL kg-1 min-1) and Bertioga (36.98 +/- 5.62 mL kg-1 min-1; P = 0.01), in the heart rate at AT (AT HR; Cubatão 152.08 +/- 14.86 bpm, Bertioga 157.44 +/- 13.64 bpm; P = 0.001), and in percent maximal oxygen consumption at AT (AT%VO2max; Cubatão 64.56 +/- 6.55%, Bertioga 67.40 +/- 5.35%; P = 0.03). However, there were no differences in VO2max, maximal heart rate or velocity at AT (ATvel) observed in firemen between towns. The acute exposure to pollutants in Cubatão, SP, caused a significant reduction in the performance at submaximal levels of physical exertion.

Impact of acute exposure to air pollution on the cardiorespiratory performance of military firemen

The objective of the present study was to determine the impact of acute short-term exposure to air pollution on the cardiorespiratory performance of military fireman living and working in the city of Guarujá, São Paulo, Brazil. Twenty-five healthy non-smoking firemen aged 24 to 45 years had about 1 h of exposure to low and high levels of air pollution. The tests consisted of two phases: phase A, in Bertioga, a town with low levels of air pollution, and phase B, in Cubatão, a polluted town, with a 7-day interval between phases. The volunteers remained in the cities (Bertioga/Cubatão) only for the time required to perform the tests. Cumulative load 10 ± 2 min-long exertion tests were performed on a treadmill, consisting of a 2-min stage at a load of 7 km/h, followed by increasing exertion of 1 km h-1 min-1 until the maximum individual limit. There were statistically significant differences (P < 0.05) in anaerobic threshold (AT) between Cubatão (35.04 ± 4.91 mL kg-1 min-1) and Bertioga (36.98 ± 5.62 mL kg-1 min-1; P = 0.01), in the heart rate at AT (AT HR; Cubatão 152.08 ± 14.86 bpm, Bertioga 157.44 ± 13.64 bpm; P = 0.001), and in percent maximal oxygen consumption at AT (AT percentVO2max; Cubatão 64.56 ± 6.55 percent, Bertioga 67.40 ± 5.35 percent; P = 0.03). However, there were no differences in VO2max, maximal heart rate or velocity at AT (ATvel) observed in firemen between towns. The acute exposure to pollutants in Cubatão, SP, caused a significant reduction in the performance at submaximal levels of physical exertion.

Changes in ventilatory threshold at high altitude: effect of antioxidants.

PURPOSE: To investigate the effects of prolonged hypoxia and antioxidant supplementation on ventilatory threshold (VT) during high-altitude (HA) exposure (4300 m). METHODS: Sixteen physically fit males (25 +/- 5 yr; 77.8 +/- 8.5 kg) performed an incremental test to maximal exertion on a cycle ergometer at sea level (SL). Subjects were then matched on VO2peak, ventilatory chemosensitivity, and body mass and assigned to either a placebo (PL) or antioxidant (AO) supplement group in a randomized, double-blind manner. PL or AO (12 mg of beta-carotene, 180 mg of alpha-tocopherol acetate, 500 mg of ascorbic acid, 100 mug of selenium, and 30 mg of zinc daily) were taken 21 d prior to and for 14 d at HA. During HA, subjects participated in an exercise program designed to achieve an energy deficit of approximately 1400 kcal.d(-1). VT was reassessed on the second and ninth days at HA (HA2, HA9). RESULTS: Peak power output (Wpeak) and VO2peak decreased (28%) in both groups upon acute altitude exposure (HA2) and were unchanged with acclimatization and exercise (HA9). Power output at VT (WVT) decreased from SL to HA2 by 41% in PL, but only 32% in AO (P < 0.05). WVT increased in PL only during acclimatization (P < 0.05) and matched AO at HA9. Similar results were found when VT was expressed in terms of % Wpeak and % VO2peak. CONCLUSIONS: VT decreases upon acute HA exposure but improves with acclimatization. Prior AO supplementation improves VT upon acute, but not chronic altitude exposure.

Measurement of neural respiratory drive in patients with COPD.

Assessment of neural respiratory drive may be useful in patients with chronic obstructive pulmonary disease (COPD) for diverse clinical and academic reasons. We hypothesised that the oesophageal diaphragm EMG during CO2 rebreathing and treadmill exercise could be used for this purpose. The oesophageal catheter consisted of nine consecutive recording electrode coils, which formed five pairs of electrodes with an inter-electrode distance 3.2 cm within a recording pair. Each coil was 1cm in length and the gap between adjacent coils was 0.5 mm. Maximal isometric contractions at functional residual capacity (FRC) and maximal voluntary inspirations from FRC to total lung capacity (TLC) were performed. All subjects performed CO2 rebreathing until end-tidal CO2 was approximately 9% or they became intolerably breathless. There was a good linear relationship between peak of root mean square (RMS) of the diaphragm EMG and end-tidal CO2 (r = 0.92 +/- 0.06) during CO2 rebreathing. The method was also shown to be feasible during exercise. It is concluded that the diaphragm EMG recorded from an oesophageal electrode is a useful technique to assess neural respiratory drive in patients with COPD.

Effects of inhaled furosemide on exertional dyspnea in chronic obstructive pulmonary disease.

The aim of this study is to investigate the effects of inhaled furosemide on the sensation of dyspnea produced during exercise in patients with stable chronic obstructive pulmonary disease (COPD). In a double-blind, randomized, crossover study we compared the effect of inhaled furosemide on dyspneic sensation during exercise testing with that of placebo. Spirometry and incremental and constant-load exercise testing were performed after inhalation of placebo or furosemide on 2 separate days in 19 patients with moderate or severe COPD. Subjects were asked to rate their sensation of respiratory discomfort using a 100-mm visual analog scale. There was significant improvement in mean FEV1 and FVC after inhalation of furosemide (p = 0.038 and 0.005, respectively) but not after placebo. At standardized exercise time during constant-load exercise testing but not during incremental exercise, the mean dyspneic visual analog scale score was lower after inhalation of furosemide compared with placebo (33.7 +/- 25.2 vs. 42.4 +/- 24.0 mm, respectively, p = 0.014). We conclude that inhalation of furosemide alleviates the sensation of dyspnea induced by constant-load exercise testing in patients with COPD and that there is significant bronchodilation after inhalation of furosemide compared with placebo in these patients.

Acute formoterol administration has no ergogenic effect in nonasthmatic athletes.

PURPOSE: To determine the effect of formoterol (formoterol fumarate dihydrate) on the aerobic and anaerobic capacities of highly trained athletes. METHODS: 10 male athletes (age = 26.2 +/- 0.9, VO(2max) = 65.6 +/- 2.4 mL x kg(-1) x min(-1)) with minimal bronchial reactivity to aerosols (i.e., negative methacholine challenge test) completed three identical exercise sessions differing only by the medication administered. Formoterol (F) a long-acting beta(2)-agonist, presently not approved for international competition by the I.O.C. Medical committee, was compared with salbutamol (S), an accepted bronchodilator, and a placebo (P). Formoterol (12 microg), salbutamol (400 microg), or placebo was administered by a Turbuhaler, 10 min before exercise testing in a double-blind, randomized, three-way crossover design. Testing sessions included a Wingate anaerobic test followed 15 min later by an incremental cycle ergometer test to exhaustion. RESULTS: There were no significant differences between the groups in VO(2max) (F = 66.5 +/- 2.7; S = 67.8 +/- 2.5; P = 67.5 +/- 2.1 mL x kg(-1) x min(-1)) or Wingate peak power (F = 885 +/- 40; S = 877 +/- 40; P = 885 +/- 44 W) values. During the maximal aerobic test, no differences were observed in maximum minute ventilation, respiratory exchange ratio, heart rate, or work between the three experimental conditions. Also, there were no differences in the Wingate anaerobic test variables, total work, or fatigue index. CONCLUSION: Formoterol, administered in one aerosolized therapeutic dose, does not have an ergogenic effect in elite athletes without asthma.

Decreased respiratory depression during emergence from anesthesia with sevoflurane/N2O than with sevoflurane alone.

PURPOSE: To investigate ventilation and gas elimination during the emergence from inhalational anesthesia with controlled normoventilation with either sevoflurane/N2O or sevoflurane alone. METHODS: Twenty-four ASA I-II patients scheduled for abdominal hysterectomy were randomly allocated to receive either 1.3 MAC sevoflurane/N2O (n = 12) or equi-MAC sevoflurane (n = 12) in 30% oxygen (O2). Expired minute ventilation volumes (V(E)), end-tidal (ET) concentrations of O2, carbon dioxide (CO2), sevoflurane and N2O as well as pulse oximetry saturation (SpO2) and CO2 elimination rates (VCO2) were measured. The ET concentrations of sevoflurane and N2O were converted to total MAC values and gas elimination was expressed in terms of MAC reduction. Time to resumption of spontaneous breathing and extubation were recorded and arterial blood gas analysis was performed at the end of controlled normoventilation and at the beginning of spontaneous breathing. RESULTS: Resumption of spontaneous breathing and extubation were 8 and 13 min less, respectively, in the sevoflurane/N2O than in the sevoflurane group. Spontaneous breathing was resumed in both groups when pH had decreased by 0.07-0.08 and PaCO2 increased by 1.3-1.5 kPa. Depression of V(E) and VCO2 were less, and MAC reduction more rapid in the sevoflurane/N2O than in the sevoflurane group. CONCLUSIONS: Respiratory recovery was faster after sevoflurane/N2O than sevoflurane anesthesia. Changes in pH and PaCO2 rather than absolute values were important for resumption of spontaneous breathing after controlled normoventilation. In both groups, the tracheas were extubated at about 0.2 MAC.

The effect of training and epinephrine infusion on ratings of perceived exertion (RPE).

Seven untrained males (mean age [+/-SD] = 25.6+/-3.9 yr, mean ht = 177.0+/-5.9 cm, mean wt = 65.8+/-7.4 kg) completed a 6-week exercise program (cycle ergometer). Prior to training, and at the end of each week of training, each subject performed a 20 min constant-power exercise test (absolute power was the same each week). At the end of the six week training program (within a few days), an additional 20 min constant-power test was performed, during which epinephrine was infused at a rate of 100 ng x kg(-1) x min(-1) over the final 10 min of exercise. Training significantly (P<0.05) reduced end-exercise ratings of perceived exertion (RPE), plasma epinephrine concentration [Epi], plasma norepinephrine concentration [NE], blood lactate concentration [La-], minute ventilation (V(E)), heart rate (HR), and blood glucose concentration [Glc]. Epinephrine infusion failed to increase RPE despite significant (p < 0.05) increases in [Epi], [La-], V(E) and [Glc]. Therefore, the present data indicate that RPE during exercise is not causally related to changes in plasma [Epi]. It also appears that modest changes in plasma [NE], blood [La-], V(E) and blood [Glc] during constant-power cycle ergometry (as observed during Epi infusion) do not impact RPE.

Effects of almitrine on the ventilatory control, breathing pattern and maximal exercise tolerance in hypoxemic patients with chronic obstructive pulmonary disease.

Almitrine bismesylate improves arterial blood gases in patients with chronic obstructive pulmonary disease (COPD), but side effects such as increase of ventilatory drive and dyspnea have been reported in some studies. We studied 18 COPD patients (mean age = 59.1 years; mean FEV1 = 0.92 1; mean PaO2 = 58.6 mmHg) in a double-blind randomized study using placebo or almitrine 50 mg twice a day by mouth, for 60 days. In contrast to the placebo group, 40% of the patients in the almitrine group presented a significant increase in PaO2 and a decrease in P(A-a)O2 > or = 5 mmHg during submaximal exercise after 60 days of treatment. Ventilatory drive and the breathing pattern were measured at rest and during submaximal exercise. Both groups showed high levels of ventilatory drive and a tachypneic breathing pattern before drug treatment and no modification was found 30 and 60 days after treatment. Metabolic, cardiovascular and ventilatory variables were studied during an incremental to maximum exercise symptom-limited test (cycloergometry). Maximal VO2 ranged from 46 to 52% and heart rate from 76 to 78% in relation to the predicted values. The percent ratio of ventilation at maximal exercise to maximal voluntary ventilation at rest ranged from 86 to 94%. These results show that the reduction of ventilatory capacity was the main factor decreasing the aerobic performance of our COPD patients. Maximal exercise tolerance (VO2 max) did not change after almitrine treatment. Negative factors like an increase in neuromuscular drive did not occur, and positive factors like an increase in PaO2 and oxygen transport had no critical influence on exercise performance in our ventilatory-limited COPD patients.