Effect of naloxone on perceived exertion and exercise capacity during maximal cycle ergometry

2002 ◽  
Vol 93 (6) ◽  
pp. 2023-2028 ◽  
Author(s):  
Anthony L. Sgherza ◽  
Kenneth Axen ◽  
Randi Fain ◽  
Robert S. Hoffman ◽  
Christopher C. Dunbar ◽  
...  
Keyword(s):  
Exercise Capacity ◽  
Perceived Exertion ◽  
Minute Ventilation ◽  
Work Capacity ◽  
Cycle Ergometer ◽  
Endogenous Opioids ◽  
Opioid Antagonist ◽  
Double Blind ◽  
Cycle Ergometer Test ◽  
Physiological Limits

We assessed the effects of naloxone, an opioid antagonist, on exercise capacity in 13 men and 5 women (mean age = 30.1 yr, range = 21–35 yr) during a 25 W/min incremental cycle ergometer test to exhaustion on different days during familiarization trial and then after 30 mg (iv bolus) of naloxone or placebo (Pl) in a double-blind, crossover design. Minute ventilation (V˙e), O2 consumption (V˙o 2), CO2 production, and heart rate (HR) were monitored. Perceived exertion rating (0-10 scale) and venous samples for lactate were obtained each minute. Lactate and ventilatory thresholds were derived from lactate and gas-exchange data. Blood pressure was obtained before exercise, 5 min postinfusion, at maximum exercise, and 5 min postexercise. There were no control-Pl differences. The naloxone trial demonstrated decreased exercise time (96% Pl; P < 0.01), total cumulative work (96% Pl; P < 0.002), peakV˙o 2 (94% Pl; P < 0.02), and HR (96% Pl; P < 0.01). Other variables were unchanged. HR and V˙e were the same at the final common workload, but perceived exertion was higher (8.1 ± 0.5 vs. 7.1 ± 0.5) after naloxone than Pl ( P < 0.01). The threshold for effort perception amplification occurred at ∼60 ± 4% of Pl peakV˙o 2. Thus we conclude that peak work capacity was limited by perceived exertion, which can be attenuated by endogenous opioids rather than by physiological limits.

scholarly journals Special Training of Inspiratory Muscles in Fitness Activities and Exercise Capacity in Young Women

2017 ◽  
Vol 18 (3) ◽  
Author(s):  
Viktor Mishchenko ◽  
Stanislaw Sawczyn ◽  
Agnieszka Cybulska ◽  
Marcin Pasek
Keyword(s):  
Oxygen Uptake ◽  
Exercise Capacity ◽  
Young Women ◽  
Vital Capacity ◽  
Perceived Exertion ◽  
Minute Ventilation ◽  
Work Capacity ◽  
Control Group ◽  
Inspiratory Muscles ◽  
Fitness Training

AbstractPurpose. The aim of the study was to determine if an 8-week-long endurance fitness training with elastic belts would increase the strength-endurance of the inspiratory muscles and lung function characteristics, and to assess whether these changes were consistent with an increase in aerobic power and exercise capacity in healthy young women. Methods. Twenty-two females aged 20-25 years were randomly allocated into 2 groups. The experimental group preformed 8-week-long exercises on stationary bikes with an elastic belt on the lower part of the chest. The control group underwent the same workout, without elastic belts. Vital capacity, forced vital capacity, maximal voluntary ventilation, maximal inspiratory and expiratory pressure, sustained maximal inspiratory pressure, physical activity status, and perceived exertion scores were measured. In the incremental exercise test, work capacity and maximal oxygen uptake were assessed. Tidal volume, minute ventilation (VE), oxygen uptake (VO

Effect of beta-blockade on the drift in O2 consumption during prolonged exercise

1988 ◽  
Vol 64 (2) ◽  
pp. 753-758 ◽  
Author(s):  
J. K. Kalis ◽  
B. J. Freund ◽  
M. J. Joyner ◽  
S. M. Jilka ◽  
J. Nittolo ◽  
...  
Keyword(s):  
Heart Rate ◽  
Minute Ventilation ◽  
Cycle Ergometer ◽  
Beta Blockade ◽  
Adrenergic Blockade ◽  
Maximal Heart Rate ◽  
O2 Consumption ◽  
Double Blind ◽  
Cycle Ergometer Test ◽  
Ergometer Test

The effect of beta-adrenergic blockade on the drift in O2 consumption (VO2 drift) typically observed during prolonged constant-rate exercise was studied in 14 healthy males in moderate heat at 40% of maximal O2 consumption (VO2max). After an initial maximum cycle ergometer test to determine the subjects' control VO2max, subjects were administered each of three medications: placebo, atenolol (100 mg once daily), and propranolol (80 mg twice daily), in a randomized double-blind fashion. Each medication period was 5 days in length and was followed by a 4-day washout period. On the 3rd day of each medication period, subjects performed a maximal cycle ergometer test. On the final day of each medication period, subjects exercised at 40% of their control VO2max for 90 min on a cycle ergometer in a warm (31.7 +/- 0.3 degrees C) moderately humid (44.7 +/- 4.7%) environment. beta-Blockade caused significant (P less than 0.05) reductions in VO2max, maximal minute ventilation (VEmax), maximal heart rate (HRmax), and maximal exercise time. Significantly greater decreases in VO2max, VEmax, and HRmax were associated with the propranolol compared with the atenolol treatment. During the 90-min submaximal rides, beta-blockade significantly reduced heart rate. Substantially lower values for O2 consumption (VO2) and minute ventilation (VE) were observed with propranolol compared with atenolol or placebo. Furthermore, VO2 drift and HR drift were observed under atenolol and placebo conditions but not with propranolol. Respiratory exchange ratio decreased significantly over time during the placebo and atenolol trials but did not change during the propranolol trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Failure of Glycine-Arginine-α-Ketoisocaproic Acid to Improve High-Intensity Exercise Performance in Trained Cyclists

2011 ◽  
Vol 21 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Lukas Beis ◽  
Yaser Mohammad ◽  
Chris Easton ◽  
Yannis P. Pitsiladis
Keyword(s):  
Exercise Performance ◽  
High Intensity ◽  
Perceived Exertion ◽  
Cycle Ergometer ◽  
High Intensity Exercise ◽  
Ratings Of Perceived Exertion ◽  
Mean Power ◽  
Double Blind ◽  
Oral Supplementation ◽  
Experimental Trials

Oral supplementation with glycine-arginine-α-ketoisocaproic acid (GAKIC) has previously been shown to improve exhaustive high-intensity exercise performance. There are no controlled studies involving GAKIC supplementation in well-trained subjects. The aim of the current study was to examine the effects of GAKIC supplementation on fatigue during high-intensity, repeated cycle sprints in trained cyclists. After at least 2 familiarization trials, 10 well-trained male cyclists completed 2 supramaximal sprint tests each involving 10 sprints of 10 s separated by 50-s rest intervals on an electrically braked cycle ergometer. Subjects ingested 11.2 g of GAKIC or placebo (Pl) during a period of 45 min before the 2 experimental trials, administered in a randomized and double-blind fashion. Peak power declined from the 1st sprint (M ± SD; Pl 1,332 ± 307 W, GAKIC 1,367 ± 342 W) to the 10th sprint (Pl 1,091 ± 229 W, GAKIC 1,061 ± 272 W) and did not differ between conditions (p = .88). Mean power declined from the 1st sprint (Pl 892 ± 151 W, GAKIC 892 ± 153 W) to the 10th sprint (Pl 766 ± 120 W, GAKIC 752 ± 138 W) and did not differ between conditions (p = .96). The fatigue index remained at ~38% throughout the series of sprints and did not differ between conditions (p = .99). Heart rate and ratings of perceived exertion increased from the 1st sprint to the 10th sprint and did not differ between conditions (p = .11 and p = .83, respectively). In contrast to previous studies in untrained individuals, these results suggest that GAKIC has no ergogenic effect on repeated bouts of high-intensity exercise in trained individuals.

The Effects of Ingesting Polylactate or Glucose Polymer Drinks during Prolonged Exercise

1991 ◽  
Vol 1 (3) ◽  
pp. 249-256 ◽  
Author(s):  
Thomas D. Fahey ◽  
James D. Larsen ◽  
George A. Brooks ◽  
William Colvin ◽  
Steven Henderson ◽  
...  
Keyword(s):  
Perceived Exertion ◽  
Prolonged Exercise ◽  
Venous Blood ◽  
Sodium Lactate ◽  
Cycle Ergometer ◽  
Fluid Replacement ◽  
Double Blind ◽  
Sodium Potassium ◽  
Glucose Polymer ◽  
Skin Temperatures

Five trained, fasted male cyclists rode a cycle ergometer three times at 50% of,max for 180 min. Using a balanced order, double-blind procedure,subjects were given either a solution containing polylactate (PL: 80% polylactate, 20% sodium lactate, in 7% solution with water), glucose polymer (GP: multidextrin in 7% solution with water), or control (C: water sweetened with aspartame) 5 min before exercise and at 20-min intervals during exercise. Venous blood samples were taken at rest and at 20-min intervals during exercise. In general, PL and GP rendered similar results except that pH and bicarbonate () were higher in PL. There were no differences between treatments in perceived exertion, sodium, potassium, chloride, lactate, heart rate, oxygen consumption, rectal temperature, or selected skin temperatures. These data show that polylactate may help maintain blood glucose and enhance blood buffering capacity during prolonged exercise and could be a useful component in an athletic fluid replacement beverage.

scholarly journals Acetazolamide reduces exercise capacity following a five-day ascent to 4559 m on Monte Rosa

2017 ◽  
Author(s):  
Arthur R. Bradwell ◽  
Kimberly Ashdown ◽  
Carla Gallagher ◽  
John Delamere ◽  
Owen D. Thomas ◽  
...  
Keyword(s):  
Exercise Capacity ◽  
Minute Ventilation ◽  
Acute Mountain Sickness ◽  
Bicycle Ergometer ◽  
Gas Analysis ◽  
Base Line ◽  
Older Individuals ◽  
Double Blind ◽  
Age Related ◽  
End Tidal

Acetazolamide (Az) is widely used to prevent and treat the symptoms of acute mountain sickness (AMS) but whether it alters exercise capacity at high altitude is unclear. Az (250 mg twice daily) or placebo were administered to 20 healthy adults (age range, 21-77 years) in a double-blind, randomized manner. Participants ascended over five days to 4559 m, before undertaking an incremental exercise test to exhaustion on a bicycle ergometer, with breath-by-breath gas measurements recorded using a portable gas analysis system. Maximum power output (Pmax) was reduced on Az compared with placebo (p=0.03), as was maximum O2 uptake (VO2max) (20.7 vs 24.6 mL/kg/min; p=0.06) and maximum expired CO2 (VCO2max) (23.4 vs 29.5 mL/kg/min; p=0.01). Comparing individuals matched for similar characteristics, Az-treated participants had smaller changes than placebo-treated participants in minute ventilation (88 vs 116 L/min: p=0.05), end tidal O2 (6.6 vs 9.3 mm Hg: p=0.009), end-tidal CO2 (−2.3 vs −4.2 mm Hg: p=0.005), VO2max (9.8 vs 13.8 mL/kg/min; p=0.04) and VCO2max (14.7 vs 20.8 mL/kg/min; p=0.009). There was a negative correlation between the mean ages of paired vs placebo-treated individuals and differences in Pmax reductions from base-line to altitude (r =−0.83: p<0.005) and HRmax at altitude (r=−0.71; p=0.01). Glomerular filtration rate (measured at sea-level) declined with increasing age (r=−0.69; p=0.001). Thus, 250mg of Az twice daily reduced exercise performance, particularly in older individuals. The age-related effects of Az may reflect higher tissue concentrations due to reduced drug clearance in older people.

Effect of ENDUROX™ on Metabolic Responses to Submaximal Exercise

1999 ◽  
Vol 9 (4) ◽  
pp. 434-442 ◽  
Author(s):  
Samuel N. Cheuvront ◽  
Robert J. Moffatt ◽  
Kyle D. Biggerstaff ◽  
Shawn Bearden ◽  
Paul McDonough
Keyword(s):  
Oxygen Consumption ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Minute Ventilation ◽  
Rating Of Perceived Exertion ◽  
Peak Oxygen Consumption ◽  
Metabolic Responses ◽  
Double Blind ◽  
Serum Glycerol ◽  
Male Subjects

Claims that ENDUROX™ enhances performance by altering metabolic responses to exercise were tested. In a double-blind crossover design, 10 male subjects were randomly assigned to consume 400 mg of placebo or 800 mg ENDUROX™ for 7 days. Cycle ergometry was performed for 30 minutes at 25%, followed by 10 min at 65% of peak oxygen consumption. After a 1-week washout period, subjects performed the identical exercise protocol following 7 days of reciprocal supplemental conditions. Expired gases were collected and analyzed continuously for oxygen consumption, minute ventilation, and respiratory exchange ratio. Heart rate, blood pressure, rating of perceived exertion, blood lactate, and serum glycerol data were also collected at regular intervals. A two-way ANOVA with repeated measures revealed no significant main or interaction effects involving group differences (p > 0.05) between trials for any variable during rest, 25% or 65% (VO2 peak), or recovery. Our findings do not support the ergogenic claims for ENDUROX™.

Acetazolamide alters temperature regulation during submaximal exercise

1990 ◽  
Vol 69 (4) ◽  
pp. 1402-1407 ◽  
Author(s):  
W. F. Brechue ◽  
J. M. Stager
Keyword(s):  
Stroke Volume ◽  
Minute Ventilation ◽  
Exercise Bout ◽  
Cycle Ergometer ◽  
Submaximal Exercise ◽  
Whole Body ◽  
Co2 Removal ◽  
O2 Uptake ◽  
Double Blind ◽  
Hypoxic Conditions

Acetazolamide (ACZ), a potent carbonic anhydrase inhibitor, is known to decrease submaximal exercise tolerance under normoxic and hypoxic conditions. These decrements in performance occur despite the maintenance of O2 consumption and CO2 removal. Because ACZ is a diuretic, it induces a moderate hypohydration that may have a role in reducing the ability to sustain exercise through cardiovascular and thermoregulatory impairment. To investigate this potential impairment, seven healthy males between 21 and 35 yr of age were studied in a double-blind crossover design (placebo vs. ACZ). ACZ was administered in three 250-mg oral doses 14, 8, and 2 h before exercise. Subjects exercised at 70% peak O2 uptake for 30 min on a cycle ergometer in a normoxic thermoneutral environment (25 degrees C, 40% relative humidity). Results indicate that exercise minute ventilation was greater but O2 uptake, CO2 output, and respiratory exchange ratio did not differ with ACZ. ACZ led to lower mean skin (0.7 degrees C), higher rectal (0.6 degrees C), and higher mean body temperatures (0.4 degrees C) after 30 min of exercise. Whole-body sweat loss was reduced 23%, and heat storage during the exercise bout was increased 55%. Stroke volume decreased 25%, and arteriovenous O2 difference increased 15%. A significant inverse relationship (r = -0.63) between heart rate and stroke volume was observed. It is concluded that previously reported decreases in the ability to sustain submaximal exercise with ACZ may be related to hypohydration-induced impairment of the cardiovascular and thermoregulatory systems.

Effects of a Mineral Antioxidant Complex on Clinical Safety, Body Water, Lactate Response, and Aerobic Performance in Response to Exhaustive Exercise

2010 ◽  
Vol 20 (5) ◽  
pp. 381-392 ◽  
Author(s):  
Vincent J. Dalbo ◽  
Michael D. Roberts ◽  
Scott E. Hassell ◽  
Jordan R. Moon ◽  
Chad M. Kerksick
Keyword(s):  
Perceived Exertion ◽  
Rice Flour ◽  
Order Effect ◽  
Cycle Ergometer ◽  
Body Water ◽  
Interactive Effects ◽  
Aerobic Performance ◽  
Double Blind ◽  
Clinical Safety ◽  
Total Body

Background:This investigation examined the safety and efficacy of a silica-based mineral antioxidant complex (MAC) that has been suggested to influence body water and buffer lactate.Methods:In a double-blind, randomized crossover design, male participants completed testing for 3 conditions: water only (baseline), rice flour (placebo), and MAC supplementation. Participants visited the laboratory on 5 occasions: familiarization, baseline, Testing Day 1, washout, and Testing Day 2. Baseline and Testing Days 1 and 2 consisted of fasting blood, pre- to postexercise body-water assessment and determination of VO2peak on a cycle ergometer. The supplementation protocols were separated by 1 wk and balanced to minimize an order effect.Results:No differences between conditions were found for heart rate, blood pressure, or serum-safety markers (p > .05). Before exercise there were no differences between conditions for total body water (TBW), intracellular water (ICW), or extracellular water (ECW). No significant interactive effects for supplementation and exercise were found for TBW, ICW, or ECW (p > .05). A time effect for TBW (p < .01) and ICW (p < .001) was present. Within-group changes in TBW occurred in the MAC condition, and within-group changes for ICW occurred in the MAC and placebo conditions. Ratings of perceived exertion and blood lactate increased (p < .05) with exercise. No significant effects were found for performance variables.Conclusions:MAC supplementation had no impact on aerobic exercise performance and lactate response. Increases in TBW and ICW occurred after MAC consumption, but these changes appeared to have minimal physiological impact.

scholarly journals Redox and autonomic responses to acute exercise-post recovery following Opuntia ficus-indica juice intake in physically active women

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Marianna Bellafiore ◽  
Anna Maria Pintaudi ◽  
Ewan Thomas ◽  
Luisa Tesoriere ◽  
Antonino Bianco ◽  
...  
Keyword(s):  
Placebo Group ◽  
Acute Exercise ◽  
Redox Balance ◽  
Cycle Ergometer ◽  
Double Blind ◽  
Opuntia Ficus Indica ◽  
Physically Active ◽  
Cycle Ergometer Test ◽  
Post Test ◽  
Total Antioxidant

Abstract Background The aim of this study was to investigate if the supplementation with Opuntia ficus-indica (OFI) juice may affect plasma redox balance and heart rate variability (HRV) parameters following a maximal effort test, in young physically active women. Methods A randomized, double blind, placebo controlled and crossover study comprising eight women (23.25 ± 2.95 years, 54.13 ± 9.05 kg, 157.75 ± 0.66 cm and BMI of 21.69 ± 0.66 kg/m2) was carried out. A juice containing OFI diluted in water and a Placebo solution were supplied (170 ml; OFI = 50 ml of OFI juice + 120 ml of water; Placebo = 170 ml beverage without Vitamin C and indicaxanthin). Participants consumed the OFI juice or Placebo beverage every day for 3 days, before performing a maximal cycle ergometer test, and for 2 consecutive days after the test. Plasma hydroperoxides and total antioxidant capacity (PAT), Skin Carotenoid Score (SCS) and HRV variables (LF, HF, LF/HF and rMSSD) were recorded at different time points. Results The OFI group showed significantly lower levels of hydroperoxides compared to the Placebo group in pre-test, post-test and 48-h post-test. PAT values of the OFI group significantly increased compared to those of the Placebo group in pre-test and 48-h post-test. SCS did not differ between groups. LF was significantly lower in the OFI group 24-h after the end of the test, whereas rMSSD was significantly higher in the OFI group 48-h post-test. Conclusion OFI supplementation decreased the oxidative stress induced by intense exercise and improved autonomic balance in physically active women.

scholarly journals Caffeine, exercise physiology, and time-trial performance: no effect of ADORA2A or CYP1A2 genotypes

2020 ◽  
Author(s):  
Mark Glaister ◽  
Kiran Chopra ◽  
Ana Pereira De Sena ◽  
Cassie Sternbach ◽  
Liridon Morina ◽  
...  
Keyword(s):  
Perceived Exertion ◽  
Minute Ventilation ◽  
Physiological Responses ◽  
Exercise Physiology ◽  
Time Trial ◽  
Submaximal Exercise ◽  
Controlled Study ◽  
Double Blind ◽  
Time Trial Performance ◽  
Trial Performance

The aim of this study was to investigate the influence of ADORA2A and CYP1A2 genotypes on the physiological and ergogenic effects of caffeine. Sixty-six male cyclists were screened for ADORA2A and CYP1A2 genotypes; with 40 taking part subsequently in a randomised, double-blind, placebo-controlled study. Trial 1 was used to establish the V̇O2-power output relationship and V̇O2max. In trials 2 and 3, participants ingested 5 mg·kg-1 of caffeine or placebo one hour before completing a submaximal incremental cycling test, followed by a time-trial (~ 30 mins). Relative to placebo, caffeine led to a significant reduction in time to complete the time-trial (caffeine: 29.7 ± 1.8 mins; placebo: 30.8 ± 2.3 mins); but there was no effect of genotype. During submaximal exercise, caffeine reduced mean heart rate by 2.9 ± 3.7 b·min-1, with effects dissipating as exercise intensity increased. Caffeine also significantly reduced perceived exertion by 0.5 ± 0.8, and increased blood lactate by 0.29 ± 0.42 mmol·L-1, respiratory exchange ratio by 0.013 ± 0.032, and minute ventilation by 3.1 ± 6.8 L·min-1. Nonetheless, there were no supplement × genotype interactions. In conclusion, caffeine influences physiological responses to submaximal exercise and improves time-trial performance irrespective of ADORA2A or CYP1A2 genotypes. Novelty •Caffeine affects physiological responses at rest and during submaximal exercise independent of ADORA2A or CYP1A2 genotypes. •Variability in the effect of caffeine on time-trial performance is not explained by ADORA2A or CYP1A2 genotypes.

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