Effects of chronic beta-adrenergic blockade on exercise training in dogs

To assess the role of beta-adrenergic stimulation in cardiovascular conditioning we examined the effects of a beta-adrenergic blocker, propranolol, in mongrel dogs during an 8-wk treadmill-training program. Seven dogs were trained without a drug (NP), six were trained on propranolol 10 mg.kg-1.day-1 (P), and five served as caged controls (C). Effective beta-adrenergic blockade was documented by a decrease in peak exercise heart rate of 54 +/- 11 (SE) beats/min (P less than 0.05) and a one-log magnitude of increase in the isoproterenol-heart rate dose-response curve. Testing was performed before drug treatment or training and again after training without the drug for 5 days. Submaximal exercise heart rate decreased similarly in both NP and P (-26 +/- 4 NP vs. -25 +/- 9 beats/min P, P less than 0.05 for both) but peak heart rate decreased only with NP (-33 +/- 9 beats/min, P less than 0.05). Treadmill exercise time increased similarly in both groups: 3.4 +/- 0.6 min in NP and 3.0 +/- 0.2 min in P (both P less than 0.05). Blood volume also increased after training in both groups: 605 +/- 250 ml (26%) in NP and 377 +/- 140 ml (17%) in P (both P less than 0.05). Submaximal exercise arterial lactates were reduced similarly in both groups but peak exercise lactate was reduced more in NP (-1.4 +/- 0.3 NP vs -0.3 +/- 0.12 mmol/l P, P less than 0.05). Lactate threshold increased in both groups but the increase was greater in NP (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

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Effects of beta-adrenergic blockade on O2 uptake during submaximal and maximal exercise

Journal of Applied Physiology ◽

10.1152/jappl.1983.54.4.901 ◽

1983 ◽

Vol 54 (4) ◽

pp. 901-905 ◽

Cited By ~ 39

Author(s):

P. A. Tesch ◽

P. Kaiser

Keyword(s):

Heart Rate ◽

Maximal Exercise ◽

Pulmonary Ventilation ◽

Submaximal Exercise ◽

Beta Blockade ◽

Adrenergic Blockade ◽

Maximal Heart Rate ◽

O2 Consumption ◽

O2 Uptake ◽

Beta Adrenergic

Changes in cardiorespiratory variables and perceived rate of exertion (RPE) were studied in 13 trained men performing cycling exercise before and after beta-adrenergic blockade. Propranolol (Inderal, 80 mg) was administered orally 2 h prior to standardized maximal and submaximal exercises. Muscle biopsies were obtained from vastus lateralis at rest for subsequent histochemical analyses of muscle fiber type distribution and capillary supply. During submaximal exercise O2 consumption decreased from 2.76 to 2.59 l . min-1 following blockade (P less than 0.01), whereas heart rate decreased from 157 to 113 beats . min-1 (P less than 0.001). Maximal O2 uptake was lowered from 3.79 to 3.26 l . min-1 (P less than 0.001) and maximal heart rate was reduced from 192 to 142 beats . min-1 (P less than 0.001) as a result of the blockade. Pulmonary ventilation was unaltered in both exercise conditions. “Local” RPE was higher (P less than 0.001) than “central” RPE after beta-blockade in both submaximal and maximal exercise. During normal condition this difference did not appear. Changes in both local and central RPE during submaximal exercise were positively correlated to changes in O2 uptake. Individual variations in the metabolic profile of the exercising muscle had no influence on beta-blockade-induced changes in O2 uptake. It is concluded that blockade of beta-adrenergic receptors reduces O2 consumption during submaximal (approximately 73% maximal O2 uptake) and maximal exercise in habitually trained men.

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Role of nitric oxide in the renin and heart rate responses to beta-adrenergic stimulation.

Hypertension ◽

10.1161/01.hyp.23.1_suppl.i49 ◽

1994 ◽

Vol 23 (1_Suppl) ◽

pp. I49-I49 ◽

Cited By ~ 14

Author(s):

I. A. Reid ◽

H. Bui ◽

L. Chou

Keyword(s):

Nitric Oxide ◽

Heart Rate ◽

Adrenergic Stimulation ◽

Beta Adrenergic

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Safety and efficacy of omaveloxolone in patients with mitochondrial myopathy

Neurology ◽

10.1212/wnl.0000000000008861 ◽

2020 ◽

Vol 94 (7) ◽

pp. e687-e698 ◽

Cited By ~ 5

Author(s):

Karen L. Madsen ◽

Astrid E. Buch ◽

Bruce H. Cohen ◽

Marni J. Falk ◽

Angela Goldsberry ◽

...

Keyword(s):

Heart Rate ◽

Mitochondrial Myopathy ◽

Lactate Production ◽

Primary Outcome Measure ◽

Submaximal Exercise ◽

Peak Exercise ◽

Exercise Heart Rate ◽

Double Blind ◽

Safety And Efficacy ◽

6Mwt Distance

ObjectiveTo investigate the safety and efficacy of escalating doses of the semi-synthetic triterpenoid omaveloxolone in patients with mitochondrial myopathy.MethodsIn cohorts of 8–13, 53 participants were randomized double-blind to 12 weeks of treatment with omaveloxolone 5, 10, 20, 40, 80, or 160 mg, or placebo. Outcome measures were change in peak cycling exercise workload (primary), in 6-minute walk test (6MWT) distance (secondary), and in submaximal exercise heart rate and plasma lactate (exploratory).ResultsNo differences in peak workload or 6MWT were observed at week 12 with omaveloxolone treatment vs placebo for all omaveloxolone dose groups. In contrast, omaveloxolone 160 mg reduced heart rate at week 12 by 12.0 ± 4.6 bpm (SE) during submaximal exercise vs placebo, p = 0.01, and by 8.7 ± 3.5 bpm (SE) vs baseline, p = 0.02. Similarly, blood lactate was 1.4 ± 0.7 mM (SE) lower vs placebo, p = 0.04, and 1.6 ± 0.5 mM (SE) lower vs baseline at week 12, p = 0.003, with omaveloxolone 160 mg treatment. Adverse events were generally mild and infrequent.ConclusionsOmaveloxolone 160 mg was well-tolerated, and did not lead to change in the primary outcome measure, but improved exploratory endpoints lowering heart rate and lactate production during submaximal exercise, consistent with improved mitochondrial function and submaximal exercise tolerance. Therefore, omaveloxolone potentially benefits patients with mitochondrial myopathy, which encourages further investigations of omaveloxolone in this patient group.Clinicaltrials.gov identifierNCT02255422.Classification of evidenceThis study provides Class II evidence that, for patients with mitochondrial myopathy, omaveloxolone compared to placebo did not significantly change peak exercise workload.

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EFFECTS OF ALPHA-ADRENERGIC STIMULATION AND BLOCKADE ON PLASMA PARATHYROID HORMONE CONCENTRATIONS IN COWS

Acta Endocrinologica ◽

10.1530/acta.0.0880535 ◽

1978 ◽

Vol 88 (3) ◽

pp. 535-544 ◽

Cited By ~ 10

Author(s):

J. W. Blum ◽

A. Guillebeau ◽

U. Binswanger ◽

P. Kunz ◽

M. Da Prada ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Fatty Acid ◽

Parathyroid Hormone ◽

Free Fatty Acid ◽

Adrenergic Blockade ◽

Adrenergic Stimulation ◽

Beta Adrenergic ◽

Later Phase ◽

Immunoreactive Parathyroid Hormone

ABSTRACT Experiments were designed to investigate responses of immunoreactive parathyroid hormone (PTH) during alpha-adrenergic stimulation and blockade in cows. Alpha-adrenergic agonists (methoxamine, phenylephrine and noradrenaline, the beta-adrenergic action of which was blocked by propranolol) did not change PTH and free fatty acid levels, whereas they characteristically increased the blood pressure and decreased the heart rate. In contrast, alpha-adrenergic blockade by phentolamine progressively increased PTH levels. The elevated PTH concentrations, associated with increased plasma noradrenaline and free fatty acid levels, rising heart rate and decreasing blood pressure, indicated that all these changes can be related to a beta-adrenergic stimulatory mechanism. Beta-adrenergic stimulation was presumably responsible for the initial elevation of PTH concentrations, whereas, during the later phase of the phentolamine infusions, a concomitant hypocalcaemia probably also produced a stimulatory effect.

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Effects of Beta-Adrenergic Blockade on Heart Rate and Blood Lactate in Children during Maximal and Submaximal Exercise

Acta Paediatrica ◽

10.1111/j.1651-2227.1967.tb05260.x ◽

1967 ◽

Vol 56 (s177) ◽

pp. 123-125 ◽

Cited By ~ 8

Author(s):

C. THORÉN

Keyword(s):

Heart Rate ◽

Blood Lactate ◽

Submaximal Exercise ◽

Adrenergic Blockade ◽

Beta Adrenergic

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O2 extraction maintains O2 uptake during submaximal exercise with β-adrenergic blockade at 4,300 m

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.3.1092 ◽

1998 ◽

Vol 85 (3) ◽

pp. 1092-1102 ◽

Cited By ~ 34

Author(s):

Eugene E. Wolfel ◽

Mark A. Selland ◽

A. Cymerman ◽

George A. Brooks ◽

Gail E. Butterfield ◽

...

Keyword(s):

Heart Rate ◽

Cardiac Output ◽

Stroke Volume ◽

High Altitude ◽

Sea Level ◽

Submaximal Exercise ◽

Whole Body ◽

Exercise Heart Rate ◽

Adrenergic Blockade ◽

Mixed Venous

Whole body O2 uptake (V˙o 2) during maximal and submaximal exercise has been shown to be preserved in the setting of β-adrenergic blockade at high altitude, despite marked reductions in heart rate during exercise. An increase in stroke volume at high altitude has been suggested as the mechanism that preserves systemic O2 delivery (blood flow × arterial O2 content) and thereby maintainsV˙o 2 at sea-level values. To test this hypothesis, we studied the effects of nonselective β-adrenergic blockade on submaximal exercise performance in 11 normal men (26 ± 1 yr) at sea level and on arrival and after 21 days at 4,300 m. Six subjects received propranolol (240 mg/day), and five subjects received placebo. At sea level, during submaximal exercise, cardiac output and O2 delivery were significantly lower in propranolol- than in placebo-treated subjects. Increases in stroke volume and O2 extraction were responsible for the maintenance of V˙o 2. At 4,300 m, β-adrenergic blockade had no significant effect onV˙o 2, ventilation, alveolar Po 2, and arterial blood gases during submaximal exercise. Despite increases in stroke volume, cardiac output and thereby O2 delivery were still reduced in propranolol-treated subjects compared with subjects treated with placebo. Further reductions in already low levels of mixed venous O2 saturation were responsible for the maintenance ofV˙o 2 on arrival and after 21 days at 4,300 m in propranolol-treated subjects. Despite similar workloads and V˙o 2, propranolol-treated subjects exercised at greater perceived intensity than subjects given placebo at 4,300 m. The values for mixed venous O2 saturation during submaximal exercise in propranolol-treated subjects at 4,300 m approached those reported at simulated altitudes >8,000 m. Thus β-adrenergic blockade at 4,300 m results in significant reduction in O2delivery during submaximal exercise due to incomplete compensation by stroke volume for the reduction in exercise heart rate. Total bodyV˙o 2 is maintained at a constant level by an interaction between mixed venous O2 saturation, the arterial O2-carrying capacity, and hemodynamics during exercise with acute and chronic hypoxia.

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P.4.f.005 Beta-adrenergic blockade impairs fear extinction in rats: role of the medial prefrontal cortex

European Neuropsychopharmacology ◽

10.1016/s0924-977x(08)70755-7 ◽

2008 ◽

Vol 18 ◽

pp. S503

Author(s):

F.H.M. Do Monte ◽

G.C. Kincheski ◽

E. Pavesi ◽

A.P. Carobrez

Keyword(s):

Prefrontal Cortex ◽

Medial Prefrontal Cortex ◽

Fear Extinction ◽

Adrenergic Blockade ◽

Beta Adrenergic

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Effect of pharmacological blockade on cardiovascular responses to voluntary and forced diving in muskrats.

Journal of Experimental Biology ◽

10.1242/jeb.198.11.2307 ◽

1995 ◽

Vol 198 (11) ◽

pp. 2307-2315 ◽

Cited By ~ 5

Author(s):

P E Signore ◽

D R Jones

Keyword(s):

Heart Rate ◽

Neural Control ◽

Peripheral Resistance ◽

Cardiovascular Responses ◽

Adrenergic Blocker ◽

Adrenergic Blockers ◽

Pharmacological Blockade ◽

Parasympathetic Influences ◽

Neural Effect

Neural control of free and forced diving bradycardia and peripheral resistance was studied in the muskrat (Ondatra zibethicus) by means of acute pharmacological blockade with the muscarinic blocker atropine, the alpha-adrenergic blocker phentolamine and the beta-adrenergic blockers nadolol and propranolol. Saline injection was used as a control. Heart rate in control animals increased before voluntary dives and dropped markedly as soon as the animals submerged. Heart rate started increasing towards the end of voluntary dives and reached pre-dive values within the first 5 s of recovery. Pre-dive and post-dive tachycardia were reduced in beta-blocked animals, emphasizing the role of the sympathetic system during the preparatory and recovery periods of voluntary dives. Diving bradycardia and the acceleration in heart rate before surfacing were abolished by atropine and unaffected by nadolol, demonstrating the importance of vagal efferent activity during diving. The results after blockade with nadolol suggest that there is an accentuated antagonism between the two branches of the autonomic nervous system during diving, so that parasympathetic influences on the heart predominate. Propranolol-treated muskrats had a higher diving heart rate than saline- and nadolol-treated animals, which may be due to a sedative effect caused by propranolol crossing the blood-brain barrier, a blockade of central catecholaminergic pathways or a peripheral neural effect, due to the anaesthetic properties of propranolol. Phentolamine did not affect diving bradycardia, indicating that diving bradycardia occurs independently of peripheral vasoconstriction.(ABSTRACT TRUNCATED AT 250 WORDS)

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Using Submaximal Exercise Heart Rate for Monitoring Cardiorespiratory Fitness Changes in Professional Soccer Players: A Replication Study

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2020-0554 ◽

2020 ◽

pp. 1-7

Author(s):

Stefan Altmann ◽

Rainer Neumann ◽

Sascha Härtel ◽

Alexander Woll ◽

Martin Buchheit

Keyword(s):

Heart Rate ◽

Potential Role ◽

Lactate Concentration ◽

Soccer Players ◽

Exercise Heart Rate ◽

Incremental Test ◽

Professional Soccer ◽

Optimal Thresholds ◽

The Moment

Purpose: To assess the value of monitoring changes in fitness in professional soccer players, using changes in heart rate at submaximal intensity (HR12km/h) over the velocity at a lactate concentration of 4 mmol/L (v4mmol/L). The authors reexamined (1) a range of threshold magnitudes, which may improve detecting substantial individual changes and (2) the agreement between changes in these 2 variables. Methods: On at least 2 occasions during different moments of the season, 97 professional soccer players from Germany (first, second, and fourth division) completed an incremental test to determine HR12km/h and v4mmol/L. Optimal thresholds for changes in HR12km/h and v4mmol/L were assessed, using various methods (eg, smallest worthwhile change + typical error [TE], successive reiterations approach). Agreement between both variable changes was examined for the whole sample (225 comparisons), 4 different subgroups (depending on the moment of the season), and in an individual over 6 years (n = 23 tests). Results: Changes of 4.5% and 6.0% for HR12km/h and v4mmol/L, respectively, were rated as optimal to indicate substantial changes in fitness. Depending on the (sub)groups analyzed, these thresholds yielded 0% to 2% full mismatches, 22% to 38% partial agreements, and 60% to 78% full agreements in terms of fitness change interpretation between both variables. Conclusions: When lactate sampling during incremental tests is not possible, practitioners willing to monitor adult professional soccer players’ (Germany; first, second, and fourth division) training status can confidently implement short, 3-minute submaximal runs, with 4.5% changes in HR12km/h being indicative of true substantial fitness changes, with 60% to 78% accuracy. Future studies should investigate the potential role of confounding factors of HR12km/h to improve changes in fitness prediction.

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