scholarly journals Adrenergic Response to Maximum Exercise of Trained Road Cyclists

2014 ◽  
Vol 40 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Grażyna Janikowska ◽  
Aleksandra Kochańska - Dziurowicz ◽  
Aleksandra Żebrowska ◽  
Aleksandra Bijak ◽  
Magdalena Kimsa
Keyword(s):  
Oxygen Uptake ◽  
Bicycle Ergometer ◽  
Adrenergic System ◽  
Plasma Catecholamine ◽  
Plasma Epinephrine ◽  
Adrenergic Response ◽  
Road Cyclists ◽  
Plasma Catecholamine Concentrations ◽  
Response To Exercise ◽  
Epinephrine Concentration

Abstract The aim of this study was to evaluate adrenergic responses in the peripheral blood of trained road cyclists at rest, at maximal intensity of incremental bicycle exercise test, and during 15 minutes of recovery, as well as the relationship between them. Competitive male road cyclists, in the pre-competitive phase of a season, mean age 21.7 ± 6.4 years, and BMI 20.7 ± 0.8 kg·m-2, performed an incremental test on a bicycle ergometer with unloaded cycling for 5 min, then increased the load to 40 W every 3 min, up to maximal exercise intensity. The plasma catecholamine concentrations (epinephrine, norepinephrine) and oxygen uptake were estimated. The expression of 132 genes related to the adrenergic system in leukocytes was measured. A statistically significant increase in plasma epinephrine concentration (p < 0.01) was observed in response to exercise. The mean of maximal oxygen uptake was 65.7 ± 5.5 ml·kg-1·min-1. The RGS2 gene expression was highest regardless of the test phase for all athletes. The effort had a statistically significant influence on ADRB2 and RAB2A expression. In addition, the RAB2A, ADM and HSPB1 expression level increased during recovery. We can conclude that plasma epinephrine concentration and genes related to the adrenergic system such as ADM, ADRB2, CCL3, GPRASP1, HSPB1, RAB2A, RGS2 and ROCK1 seem to have an influence on the response to high-intensity exercise in trained cyclists.

Catecholamine-fuel interrelationships during exercise in fasting men

1980 ◽  
Vol 48 (1) ◽  
pp. 109-113 ◽  
Author(s):  
J. M. Pequignot ◽  
L. Peyrin ◽  
G. Peres
Keyword(s):  
Maximal Oxygen Consumption ◽  
Plasma Catecholamines ◽  
Plasma Free Fatty Acid ◽  
Work Load ◽  
Bicycle Ergometer ◽  
Plasma Norepinephrine ◽  
Plasma Catecholamine ◽  
Adrenergic Response ◽  
Response To Exercise

Adrenergic response to exercise and the relationships between plasma catecholamines and blood energetic substrates were studied in sedentary men after 15 h of fasting. Subjects pedaled a bicycle ergometer until exhaustion at a work load approximating 80% maximal oxygen consumption. Working ability was diminished by the fast (P less than 0.025). Resting plasma norepinephrine level was increased by fasting. During exercise plasma epinephrine (E) and norepinephrine (NE) concentrations were more elevated in fasting subjects than in fed subjects. Plasma catecholamine (CA) levels in fasting men correlated with blood glucose, blood lactate, and plasma glycerol concentrations. There was no significative correlation between CA and plasma free fatty acid (FFA) levels. The increased adrenergic activity in fasting subjects correlated with reduced endurance time. This study emphasizes the role of CA release, probably combined with other hormonal factors, in the mobilization of energy substrates during submaximal exercise.

scholarly journals Effect of epinephrine on muscle glycogenolysis during exercise in trained men

1998 ◽  
Vol 84 (2) ◽  
pp. 465-470 ◽  
Author(s):  
M. A. Febbraio ◽  
D. L. Lambert ◽  
R. L. Starkie ◽  
J. Proietto ◽  
M. Hargreaves
Keyword(s):  
Oxygen Uptake ◽  
Muscle Glycogen ◽  
Respiratory Exchange Ratio ◽  
Peak Oxygen Uptake ◽  
Plasma Epinephrine ◽  
Epinephrine Infusion ◽  
Glycogen Utilization ◽  
Muscle Glycogen Concentration ◽  
Epinephrine Concentration

Febbraio, M. A., D. L. Lambert, R. L. Starkie, J. Proietto, and M. Hargreaves. Effect of epinephrine on muscle glycogenolysis during exercise in trained men. J. Appl. Physiol. 84(2): 465–470, 1998.—To test the hypothesis that an elevation in circulating epinephrine increases intramuscular glycogen utilization, six endurance-trained men performed two 40-min cycling trials at 71 ± 2% of peak oxygen uptake in 20–22°C conditions. On the first occasion, subjects were infused with saline throughout exercise (Con). One week later, after determination of plasma epinephrine levels in Con, subjects performed the second trial (Epi) with an epinephrine infusion, which resulted in a twofold higher ( P < 0.01) plasma epinephrine concentration in Epi compared with Con. Although oxygen uptake was not different when the two trials were compared, respiratory exchange ratio was higher throughout exercise in Epi compared with Con (0.93 ± 0.01 vs. 0.89 ± 0.01; P < 0.05). Muscle glycogen concentration was not different when the trials were compared preexercise, but the postexercise value was lower ( P < 0.01) in Epi compared with Con. Thus net muscle glycogen utilization was greater during exercise with epinephrine infusion (224 ± 37 vs. 303 ± 30 mmol/kg for Con and Epi, respectively; P < 0.01). In addition, both muscle and plasma lactate and plasma glucose concentrations were higher ( P < 0.05) in Epi compared with Con. These data indicate that intramuscular glycogen utilization, glycolysis, and carbohydrate oxidation are augmented by elevated epinephrine during submaximal exercise in trained men.

Delayed extra-adrenal epinephrine secretion after bilateral adrenalectomy in rats

1988 ◽  
Vol 254 (1) ◽  
pp. E52-E53 ◽  
Author(s):  
C. Ricordi ◽  
S. D. Shah ◽  
P. E. Lacy ◽  
W. E. Clutter ◽  
P. E. Cryer
Keyword(s):  
Detection Limit ◽  
Bilateral Adrenalectomy ◽  
Delayed Response ◽  
Plasma Catecholamine ◽  
Plasma Epinephrine ◽  
Plasma Catecholamine Concentrations ◽  
Over Time

Regulated systemic extra-adrenal epinephrine secretion has been demonstrated in long-term bilaterally adrenalectomized humans. To determine whether this is demonstrable immediately after adrenalectomy and therefore presumably ongoing when the adrenal medullas are intact or if it develops over time after the adrenal medullas are removed, we measured plasma catecholamine concentrations before and serially after bilateral adrenalectomy with cortical reimplantation in rats. We found plasma epinephrine concentrations to decrease from 244 +/- 41 pg/ml to levels that were not convincingly detectable, using a single-isotope derivative assay with a detection limit of 10 pg/ml, for up to 1 wk after bilateral adrenalectomy with cortical reimplantation. Plasma epinephrine concentrations increased thereafter, becoming detectable in all animals and averaging 31 +/- 6 pg/ml 4 wk after adrenalectomy. Thus extra-adrenal epinephrine secretion appears to be a delayed response to removal of the adrenal medullas and cannot be assumed to be ongoing when the adrenal medullas are intact.

Adrenergic blockade does not abolish elevated glucose turnover during bacterial infection

1988 ◽  
Vol 254 (1) ◽  
pp. E16-E22 ◽  
Author(s):  
D. M. Hargrove ◽  
G. J. Bagby ◽  
C. H. Lang ◽  
J. J. Spitzer
Keyword(s):  
Lactate Concentration ◽  
Glucose Turnover ◽  
Adrenergic System ◽  
Plasma Catecholamine ◽  
Adrenergic Blockade ◽  
Plasma Lactate ◽  
Glucose Kinetics ◽  
Elevated Glucose ◽  
Adrenergic Antagonists ◽  
Plasma Catecholamine Concentrations

Infusions of adrenergic antagonists were used to investigate the role of catecholamines in infection-induced elevations of glucose kinetics. Infection was produced in conscious catheterized rats by repeated subcutaneous injections of live Escherichia coli over 24 h. Glucose kinetics were measured by the constant intravenous infusion of [6-3H]- and [U-14C]glucose. Compared with noninfected rats, infected animals were hyperthermic (+1.4 degrees C) and showed increased rates of glucose appearance (45%), clearance (43%), and recycling (140%) as well as mild hyperlacticacidemia. Plasma catecholamine concentrations were increased by 50-70% in the infected rats, but there were no differences in plasma glucagon, corticosterone, and insulin levels. Adrenergic blockade was produced by primed constant infusion of both propranolol (beta-blocker) and phentolamine (alpha-blocker). A 2-h administration of adrenergic antagonists did not attenuate the elevated glucose kinetics or plasma lactate concentration in the infected rats, although it abolished the hyperthermia. In a second experiment, animals were infused with propranolol and phentolamine beginning 1 h before the first injection of E. coli and throughout the course of infection. Continuous adrenergic blockade failed to attenuate infection-induced elevations in glucose kinetics and plasma lactate. These results indicate that the adrenergic system does not mediate the elevated glucose metabolism observed in this mild model of infection.

Plasma Catecholamine Response in Trained Rats Following Hemorrhage

1996 ◽  
Vol 21 (6) ◽  
pp. 481-491 ◽  
Author(s):  
François Trudeau ◽  
Martin Milot
Keyword(s):  
Physical Training ◽  
The Other ◽  
Plasma Catecholamine ◽  
Plasma Epinephrine ◽  
Lower Heart Rate ◽  
Epinephrine Level ◽  
Similar Body ◽  
Relationship Of ◽  
The Relationship ◽  
Epinephrine Concentration

The purpose of this study was to evaluate the effect of physical training on hemorrhage-induced catecholamine release in rats. The training program consisted of swimming 5 days a week, from 15 min in the first week to 2.5 hours in the 14th week. The rats were divided into four groups. Two groups (one trained and the other untrained) were studied during hemorrhage. The third and fourth groups (one trained and the other untrained) were not subjected to hemorrhage. After 14 weeks, trained rats had a lower heart rate than untrained animals at rest (311.86 ± 8.9 vs. 361.33 ± 12.13 bpm, p <.002) for a similar body weight. The trained and untrained groups had the same blood pressure, hematocrit, and norepinephrine responses following hemorrhage. However, plasma epinephrine concentration was lower in the trained rats 15 and 25 min following hemorrhage. These results suggest a decrease of the hemorrhage-induced epinephrine secretion in trained rats. An alteration of the relationship of arterial baroreflexes and of their hormonal effectors is a potential mechanism for the reduced plasma epinephrine level in trained hemorrhaged rats. Key words: epinephrine, norepinephrine, hypotension, physical training

Decreased Platelet-Free Dopamine and Unchanged Noradrenaline and Adrenaline in Essential Hypertension

1988 ◽  
Vol 60 (02) ◽  
pp. 251-254 ◽  
Author(s):  
S E Kjeldsen ◽  
K Gjesdal ◽  
P Leren ◽  
I K Eide
Keyword(s):  
Body Weight ◽  
Essential Hypertension ◽  
Blood Platelets ◽  
Plasma Catecholamine ◽  
Catecholamine Synthesis ◽  
Hypertensive Group ◽  
Plasma Catecholamine Concentrations ◽  
Noradrenaline And Adrenaline ◽  
Over Time ◽  
Normotensive Control

SummaryThe content of free-catecholamines in blood platelets is much higher than in plasma and platelet catecholamines must be taken up from plasma, since platelets lack the enzymes for catecholamine synthesis. There is some evidence that platelet catecholamine content under certain circumstances may be an integrated measure of plasma catecholamine concentrations over time. Platelet-free catecholamines were therefore assayed in 18 untreated patients with essential hypertension and in 16 normotensive control subjects. Mean platelet-free dopamine in the hypertensive group was 3.7 ± 0.4 pg/mg platelet weight, i.e. significantly less than the 6.5 ± 0.9 pg/mg found in the normotensive (p <0.005). Platelet contents of noradrenaline and adrenaline did not differ. Decreased platelet-free dopamine and unchanged platelet noradrenaline and adrenaline persisted after adjustment for increased body weight in the hypertensive group. Although the reasons for decreased platelet-free dopamine in the hypertensive group remain unknown, this finding may add to previous result showing facilitated release of granular contents from blood platelets in patients with essential hypertension. Our data do not support platelet levels of free-catecholamines to be a marker of increased sympathetic tone in essential hypertension.

scholarly journals Physiological factors affecting performance in elite distance runners

2016 ◽  
Vol 22 ◽  
pp. 7 ◽  
Author(s):  
Leif Inge Tjelta ◽  
Shaher A. I. Shalfawi
Keyword(s):  
Oxygen Uptake ◽  
Energy System ◽  
Running Economy ◽  
Distance Runners ◽  
Energy Contribution ◽  
Physiological Factors ◽  
Factors Affecting ◽  
Air Resistance ◽  
Factors Affecting Performance ◽  
Response To Exercise

Running distances from 3000 m to the marathon (42 195 m) are events dominated by energy contribution of the aerobic energy system. The physiological factors that underlie success in these running events are maximal oxygen uptake (VO2max), running economy (RE), the utilization of the maximum oxygen uptake (%VO2max) and velocity at the anaerobic threshold (vAT). VO2max for distance runners competing on an international level has been between 70 and 87 ml/kg/min in men, and between 60 and 78.7 ml/kg/min in women, respectively. Due to lack of air resistance, laboratory testing of RE and vAT are recommended to be conducted on treadmill with 1% slope. %VO2max are in most studies expressed as the average fractional utilization of VO2max at vAT. Much of the current understanding regarding the response to exercise is based on studies of untrained and moderately trained individuals. To use this knowledge to give training recommendations to elite runners is hardly valid. Researchers should therefore exercise caution when giving training recommendations to coaches and elite distance runners based on limited available research.

Oxygen uptake, acid-base status, and performance with varied inspired oxygen fractions

1980 ◽  
Vol 49 (5) ◽  
pp. 863-868 ◽  
Author(s):  
R. P. Adams ◽  
H. G. Welch
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Uptake ◽  
Bicycle Ergometer ◽  
Carbon Dioxide Tension ◽  
Limiting Factor ◽  
Vo2 Max ◽  
And Performance ◽  
Lactate Levels ◽  
Performance Times ◽  
Inspired Oxygen

Six subjects rode a bicycle ergometer on three occasions breathing 17, 21, or 60% oxygen. In addition to rest and recovery periods, each subject worked for 10 min at 55% of maximal oxygen uptake (VO2 max) and then to exhaustion at approximately 90% VO2 max. Performance time, inspired and expired gas fractions, ventilation, and arterialized venous oxygen tension (PO2), carbon dioxide tension (PCO2), lactate, and pH were measured. VO2, carbon dioxide output, [H+]a, and [HCO3-]a were calculated. Performance times were longer in hyperoxia than in normoxia or hypoxia. However, VO2 was not different at exhaustion in normoxia compared with hypoxia or hyperoxia. During exercise, hypoxia was associated with increased lactate levels and decreased [H+]a, PCO2, and [HCO3-]a. The opposite trends were generally associated with hyperoxia. At exhaustion, [H+]a was not different under any inspired oxygen fraction. These results support the contention that oxygen is not limiting for exercise of this intensity and duration. The results also suggest that [H+] is a possible limiting factor and that the effect of oxygen on performance is perhaps related to control of [H+].

Comparison of maximal oxygen uptake values determined by predicted and actual methods

1965 ◽  
Vol 20 (3) ◽  
pp. 509-513 ◽  
Author(s):  
R. G. Glassford ◽  
G. H. Y. Baycroft ◽  
A. W. Sedgwick ◽  
R. B. J. Macnab
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Maximal Oxygen Uptake ◽  
Correlation Coefficients ◽  
Bicycle Ergometer ◽  
Exercise Heart Rate ◽  
Indirect Test ◽  
Physical Fitness Test ◽  
Mean Values ◽  
Fitness Test

Twenty-four male subjects aged 17–33 were given three direct tests of maximal oxygen uptake and one indirect test. The direct tests were those of Mitchell, Sproule, and Chapman (treadmill); Taylor, Buskirk, and Henschel (treadmill); and Åstrand (bicycle ergometer). The indirect test was the Åstrand-Ryhming nomogram (bicycle ergometer) employing heart rate response to submaximal work. In addition, the Johnson, Brouha, and Darling physical fitness test was administered. The two treadmill tests and the indirect test yielded significantly higher mean values than did the direct bicycle test. However no other significant differences in mean values occurred. Correlation coefficients between the various oxygen uptake tests as well as the fitness test were all found to be significant (.62–.83), i.e., greater than zero. No correlation obtained proved to be significantly greater than any other. The results indicate that direct treadmill tests, employing greater muscle mass, yield higher maximal oxygen uptake values (8%) than does the direct bicycle ergometer test. The Åstrand-Ryhming nomogram appears to produce a good estimation of maximal oxygen uptake, in a population unaccustomed to cycling. erobic capacity; exercise; heart rate Submitted on September 17, 1964

Sign in / Sign up

Export Citation Format

Share Document