Interleukin-6 response to exercise and high-altitude exposure: influence of α-adrenergic blockade

2001 ◽  
Vol 91 (5) ◽  
pp. 2143-2149 ◽  
Author(s):  
Robert S. Mazzeo ◽  
Danielle Donovan ◽  
Monika Fleshner ◽  
Gail E. Butterfield ◽  
Stacy Zamudio ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Interleukin 6 ◽  
Moderate Intensity ◽  
Adrenergic Blockade ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Altitude Exposure ◽  
Excretion Rates ◽  
Response To Exercise

Interleukin-6 (IL-6), an important cytokine involved in a number of biological processes, is consistently elevated during periods of stress. The mechanisms responsible for the induction of IL-6 under these conditions remain uncertain. This study examined the effect of α-adrenergic blockade on the IL-6 response to acute and chronic high-altitude exposure in women both at rest and during exercise. Sixteen healthy, eumenorrheic women (aged 23.2 ± 1.4 yr) participated in the study. Subjects received either α-adrenergic blockade (prazosin, 3 mg/day) or a placebo in a double-blinded, randomized fashion. Subjects participated in submaximal exercise tests at sea level and on days 1 and 12 at altitude (4,300 m). Resting plasma and 24-h urine samples were collected throughout the duration of the study. At sea level, no differences were found at rest for plasma IL-6 between groups (1.5 ± 0.2 and 1.2 ± 0.3 pg/ml for placebo and blocked groups, respectively). On acute ascent to altitude, IL-6 levels increased significantly in both groups compared with sea-level values (57 and 84% for placebo and blocked groups, respectively). After 12 days of acclimatization, IL-6 levels remained elevated for placebo subjects; however, they returned to sea-level values in the blocked group. α-Adrenergic blockade significantly lowered the IL-6 response to exercise both at sea level (46%) and at altitude (42%) compared with placebo. A significant correlation ( P = 0.004) between resting IL-6 and urinary norepinephrine excretion rates was found over the course of time while at altitude. In conclusion, the results indicate a role for α-adrenergic regulation of the IL-6 response to the stress of both short-term moderate-intensity exercise and hypoxia.

scholarly journals Catecholamine responses to α-adrenergic blockade during exercise in women acutely exposed to altitude

2001 ◽  
Vol 90 (1) ◽  
pp. 121-126 ◽  
Author(s):  
Robert S. Mazzeo ◽  
Joy D. Carroll ◽  
Gail. E. Butterfield ◽  
Barry Braun ◽  
Paul B. Rock ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Bicycle Ergometer ◽  
Plasma Norepinephrine ◽  
Adrenergic Blockade ◽  
Plasma Epinephrine ◽  
Exercise Tests ◽  
Altitude Exposure ◽  
Graded Exercise ◽  
Placebo Trial

We have previously documented the importance of the sympathetic nervous system in acclimatizing to high altitude in men. The purpose of this investigation was to determine the extent to which α-adrenergic blockade affects the sympathoadrenal responses to exercise during acute high-altitude exposure in women. Twelve eumenorrheic women (24.7 ± 1.3 yr, 70.6 ± 2.6 kg) were studied at sea level and on day 2 of high-altitude exposure (4,300-m hypobaric chamber) in either their follicular or luteal phase. Subjects performed two graded-exercise tests at sea level (on separate days) on a bicycle ergometer after 3 days of taking either a placebo or an α-blocker (3 mg/day prazosin). Subjects also performed two similar exercise tests while at altitude. Effectiveness of blockade was determined by phenylephrine challenge. At sea level, plasma norepinephrine levels during exercise were 48% greater when subjects were α-blocked compared with their placebo trial. This difference was only 25% when subjects were studied at altitude. Plasma norepinephrine values were significantly elevated at altitude compared with sea level but to a greater extent for the placebo (↑59%) vs. blocked (↑35%) trial. A more dramatic effect of both altitude (↑104% placebo vs. 95% blocked) and blockade (↑50% sea level vs. 44% altitude) was observed for plasma epinephrine levels during exercise. No phase differences were observed across any condition studied. It was concluded that α-adrenergic blockade 1) resulted in a compensatory sympathoadrenal response during exercise at sea level and altitude, and 2) this effect was more pronounced for plasma epinephrine.

Beta-adrenergic blockade does not prevent the lactate response to exercise after acclimatization to high altitude

1994 ◽  
Vol 76 (2) ◽  
pp. 610-615 ◽  
Author(s):  
R. S. Mazzeo ◽  
G. A. Brooks ◽  
G. E. Butterfield ◽  
A. Cymerman ◽  
A. C. Roberts ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Control Group ◽  
Adrenergic Blockade ◽  
Arterial O2 Saturation ◽  
Response To Exercise ◽  
Peak Blood

We examined the extent to which epinephrine influences blood lactate adjustments to exercise during both acute (AC) and chronic (CH) high-altitude exposure. Eleven male sea level residents were divided into a control group (n = 5) receiving a placebo or a drug group (n = 6) receiving 240 mg/day of propranolol. All subjects were studied at rest and during 45 min of submaximal exercise (approximately 50% of sea level maximal O2 uptake) at sea level (SL) and within 4 h of exposure to and after 3 wk residence at 4,300 m (summit of Pikes Peak). Blood samples were collected from the femoral artery for epinephrine and lactate concentration. Exercising blood lactate concentration was significantly different across all altitude conditions such that AC > CH > SL (P < 0.05). For a given arterial O2 saturation, mean exercising blood lactates were lower for the beta-blocked group compared with controls; however, both groups demonstrated similar patterns across all conditions. Epinephrine levels during exercise followed a similar pattern to that of lactate, averaging 0.67, 0.43, and 0.29 ng/ml for AC, CH, and SL, respectively. The correlation between lactate and epinephrine was 0.93 and 0.84 for control and beta-blocked subjects, respectively. Whereas during exercise epinephrine was consistently higher for the beta-blocked group than controls, this difference was only significant during CH exposure. The epinephrine response was related to the extent of hypoxia in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Catecholamine response during 12 days of high-altitude exposure (4,300 m) in women

1998 ◽  
Vol 84 (4) ◽  
pp. 1151-1157 ◽  
Author(s):  
Robert S. Mazzeo ◽  
Avon Child ◽  
Gail E. Butterfield ◽  
Jacinda T. Mawson ◽  
Stacy Zamudio ◽  
...  
Keyword(s):  
Blood Pressure ◽  
High Altitude ◽  
Sea Level ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Cycle Phase ◽  
Plasma Catecholamine ◽  
Nerve Activity ◽  
Altitude Exposure ◽  
Excretion Rates

We have previously demonstrated that acclimatization to high altitude elicits increased sympathetic nerve activity in men. The purpose of this investigation was to determine 1) whether women respond in a similar manner as found previously in men and 2) the extent to which menstrual cycle phase influences this response. Sixteen eumenorrheic women (age, 23.6 ± 1.2 yr; weight, 56.2 ± 4.3 kg) were studied at sea level and during 12 days of high-altitude exposure (4,300 m) in either their follicular (F; n = 11) or luteal (L; n = 5) phase. Twenty-four-hour urine samples were collected at sea level and during each day at altitude. Catecholamines were determined by high-performance liquid chromatography with electrochemical detection. Compared with sea-level values, urinary norepinephrine excretion increased significantly during altitude exposure, peaking on days 4–6. Thereafter, levels remained constant throughout the duration of altitude exposure. The magnitude of this increase was similar between the F (138%) and L (93%) phase. Urinary epinephrine levels were elevated on day 2 of altitude exposure compared with sea-level values for both F and L subjects (93%). Thereafter, urinary epinephrine excretion returned to sea-level values, and no differences were found between F and L subjects. Plasma catecholamine content was consistent with urinary values and supports the concept of an elevation in sympathetic activity over time at altitude. Mean and diastolic blood pressure as well as heart rate adjustments to high altitude correlated significantly with urinary norepinephrine excretion rates. It was concluded that 1) urinary and plasma catecholamine responses to 12 days of high-altitude exposure in women are similar to those previously documented to occur for men; 2) whereas no differences in catecholamine levels were observed between F- and L-phase assignments, for a given urinary norepinephrine excretion rate, blood pressure and heart rates were lower for F vs. L subjects; and 3) several cardiovascular adaptations associated with high-altitude exposure correlated with 24-h urinary norepinephrine excretion rates and thus sympathetic nerve activity.

scholarly journals Dietary nitrate supplementation attenuates the reduction in exercise tolerance following blood donation

2016 ◽  
Vol 311 (6) ◽  
pp. H1520-H1529 ◽  
Author(s):  
Sinead T. J. McDonagh ◽  
Anni Vanhatalo ◽  
Jonathan Fulford ◽  
Lee J. Wylie ◽  
Stephen J. Bailey ◽  
...  
Keyword(s):  
Exercise Tolerance ◽  
Peak Power ◽  
Blood Donation ◽  
Hemoglobin Concentration ◽  
Moderate Intensity ◽  
Beetroot Juice ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Dietary Nitrate ◽  
Nitrate Supplementation

We tested the hypothesis that dietary nitrate (NO3−)-rich beetroot juice (BR) supplementation could partially offset deteriorations in O2transport and utilization and exercise tolerance after blood donation. Twenty-two healthy volunteers performed moderate-intensity and ramp incremental cycle exercise tests prior to and following withdrawal of ∼450 ml of whole blood. Before donation, all subjects consumed seven 70-ml shots of NO3−-depleted BR [placebo (PL)] in the 48 h preceding the exercise tests. During the 48 h after blood donation, subjects consumed seven shots of BR (each containing 6.2 mmol of NO3−, n = 11) or PL ( n = 11) before repeating the exercise tests. Hemoglobin concentration and hematocrit were reduced by ∼8–9% following blood donation ( P < 0.05), with no difference between the BR and PL groups. Steady-state O2uptake during moderate-intensity exercise was ∼4% lower after than before donation in the BR group ( P < 0.05) but was unchanged in the PL group. The ramp test peak power decreased from predonation (341 ± 70 and 331 ± 68 W in PL and BR, respectively) to postdonation (324 ± 69 and 322 ± 66 W in PL and BR, respectively) in both groups ( P < 0.05). However, the decrement in performance was significantly less in the BR than PL group (2.7% vs. 5.0%, P < 0.05). NO3−supplementation reduced the O2cost of moderate-intensity exercise and attenuated the decline in ramp incremental exercise performance following blood donation. These results have implications for improving functional capacity following blood loss.

Altitude-induced erythrocytic 2,3-DPG and hemoglobin changes in rats of various ages

1975 ◽  
Vol 39 (2) ◽  
pp. 258-261 ◽  
Author(s):  
L. G. Martin ◽  
J. M. Connors ◽  
J. J. McGrath ◽  
J. Freeman
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Age Groups ◽  
Altitude Exposure ◽  
Simulated High Altitude ◽  
Erythropoietic Response ◽  
2,3 Dpg

Rats of various ages (2, 12, 24, and 40 mo of age) were exposed for 4 wk to either a simulated high altitude of 23,000 ft or to a Peoria, Ill., altitude of 650 ft above sea level. Hematocrit ratios, hemoglobin, and erythrocytic 2,3-diphospho-glycerate (2,3-DPG) concentrations were measured. Hematocrit and hemoglobin determinations revealed a decrease in erythrocytic content with increasing age, and the augmented erythropoietic response was seen in all age groups of animals as a result of altitude exposure. The maximal erythrocytic content of hemoglobin in the 40-mo-old animals was significantly lower than that of all other age groups. Erythrocytic 2,3-DPG levels were significantly changed by aging alone. In the 40-mo-old group there was a 35% increase over the next highest sea-level value. However, while erythrocytic 2,3-DPG content increased significantly in all other age groups following altitude exposure, it decreased 46% in the 40-mo-old group.

Regulation of hepatic glutamine metabolism during exercise in the dog

1998 ◽  
Vol 275 (4) ◽  
pp. E655-E664 ◽  
Author(s):  
Amy E. Halseth ◽  
Nathalie Rhéaume ◽  
Allison B. Messina ◽  
Erica K. Reed ◽  
Mahesh G. Krishna ◽  
...  
Keyword(s):  
Portal Vein ◽  
Acute Exercise ◽  
Vena Cava ◽  
Sampling Period ◽  
Glutamine Metabolism ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Arterial Blood ◽  
Exercise Period ◽  
Response To Exercise

The goal of this study was to determine how liver glutamine (Gln) metabolism adapts to acute exercise in the 18-h-fasted dogs ( n = 7) and in dogs that were glycogen depleted by a 42-h fast ( n = 8). For this purpose, sampling (carotid artery, portal vein, and hepatic vein) and infusion (vena cava) catheters and Doppler flow probes (portal vein, hepatic artery) were implanted under general anesthesia. At least 16 days later an experiment, consisting of a 120-min equilibration period, a 30-min basal sampling period, and a 150-min exercise period was performed. At the start of the equilibration period, a constant-rate infusion of [5-15N]Gln was initiated. Arterial Gln flux was determined by isotope dilution. Gut and liver Gln release into and uptake from the blood were calculated by combining stable isotopic and arteriovenous difference methods. The results of this study show that 1) in the 18-h-fasted dog, ∼10% and ∼35% of the basal Gln appearance in arterial blood is due to Gln release from the gut and liver, respectively, whereas ∼30% and ∼25% of the basal Gln disappearance is due to removal by these tissues; 2) extending the fast to 42 h does not affect basal arterial Gln flux or the contribution of the gut to arterial Gln fluxes but decreases hepatic Gln release, causing a greater retention of gluconeogenic carbon by the liver; 3) moderate-intensity exercise increases hepatic Gln removal from the blood regardless of fast duration but does not affect the hepatic release of Gln; and 4) Gln plays an important role in channeling nitrogen into the ureagenic pathway in the basal state, and this role is increased by ∼80% in response to exercise. These studies illustrate the quantitative importance of the splanchnic bed contribution to arterial Gln flux during exercise and the ability of the liver to acutely adapt to changes in metabolic requirements induced by the combined effects of fasting and exercise.

scholarly journals Effects of baseline heart rate at sea level on cardiac responses to high-altitude exposure

2020 ◽  
Vol 36 (5) ◽  
pp. 799-810
Author(s):  
Jingdu Tian ◽  
Chuan Liu ◽  
Yuanqi Yang ◽  
Shiyong Yu ◽  
Jie Yang ◽  
...  
Keyword(s):  
Heart Rate ◽  
High Altitude ◽  
Sea Level ◽  
Baseline Heart Rate ◽  
Altitude Exposure ◽  
Cardiac Responses

Effects of high altitude and water deprivation on arginine vasopressin release in men

2004 ◽  
Vol 286 (1) ◽  
pp. E20-E24 ◽  
Author(s):  
C. M. Maresh ◽  
W. J. Kraemer ◽  
D. A. Judelson ◽  
J. L. VanHeest ◽  
L. Trad ◽  
...  
Keyword(s):  
High Altitude ◽  
Sea Level ◽  
Arginine Vasopressin ◽  
Water Deprivation ◽  
Urine Volume ◽  
Plasma Osmolality ◽  
Vasopressin Release ◽  
Altitude Exposure ◽  
Blood Pressures ◽  
Healthy Males

High-altitude exposure changes the distribution of body water and electrolytes. Arginine vasopressin (AVP) may influence these alterations. The purpose of this study was to examine the effect of a 24-h water deprivation trial (WDT) on AVP release after differing altitude exposures. Seven healthy males (age 22 ± 1 yr, height 176 ± 2 cm, mass 75.3 ± 1.8 kg) completed three WDTs: at sea level (SL), after acute altitude exposure (2 days) to 4,300 m (AA), and after prolonged altitude exposure (20 days) to 4,300 m (PA). Body mass, standing and supine blood pressures, plasma osmolality (Posm), and plasma AVP (PAVP) were measured at 0, 12, 16, and 24 h of each WDT. Urine volume was measured at each void throughout testing. Baseline Posm increased from SL to altitude (SL 291.7 ± 0.8 mosmol/kgH2O, AA 299.6 ± 2.2 mosmol/kgH2O, PA 302.3 ± 1.5 mosmol/kgH2O, P < 0.05); however, baseline PAVP measurements were similar. Despite similar Posm values, the maximal PAVP response during the WDT (at 16 h) was greater at altitude than at SL (SL 1.7 ± 0.5 pg/ml, AA 6.4 ± 0.7 pg/ml, PA 8.7 ± 0.9 pg/ml, P < 0.05). In conclusion, hypoxia appeared to alter AVP regulation by raising the osmotic threshold and increasing AVP responsiveness above that threshold.

Heart rate response to exercise and cardiorespiratory fitness of young women at high familial risk for hypertension: effects of interval vs continuous training

2011 ◽  
Vol 18 (6) ◽  
pp. 824-830 ◽  
Author(s):  
Emmanuel G Ciolac ◽  
Edimar A Bocchi ◽  
Julia MD Greve ◽  
Guilherme V Guimarães
Keyword(s):  
Heart Rate ◽  
Exercise Training ◽  
Cardiorespiratory Fitness ◽  
Familial Risk ◽  
Moderate Intensity ◽  
Hypertensive Disorder ◽  
Moderate Intensity Exercise ◽  
Continuous Training ◽  
Response To Exercise

Exercise training is an effective intervention for treating and preventing hypertension, but its effects on heart rate (HR) response to exercise and cardiorespiratory fitness (CRF) of non-hypertensive offspring of hypertensive parents (FH+) has not been studied. We compared the effects of three times per week equal-volume high-intensity aerobic interval (AIT) and continuous moderate-intensity exercise (CME) on HR response to exercise and CRF of FH+. Forty-four young FH+ women (25.0 ± 4.4 years) randomized to control (CON; n = 12), AIT (80–90% of VO2MAX; n = 16), or CME (50–60% of VO2MAX; n = 16) performed a graded exercise test (GXT) before and after 16 weeks of follow-up to evaluate HR response to exercise and several parameters of CRF. Resting, maximal, and reserve HR did not change after the follow-up in all groups. HR recovery (difference between HRMAX and HR at 1 minute of GXT recovery phase) improved only after AIT (11.8 ± 4.9 vs. 20.6 ± 5.8 bpm, p < 0.01). Both exercise programmes were effective for improving CRF parameters, but AIT was more effective than CME for improving oxygen consumption at the respiratory compensation point (VO2RCP; 22.1% vs. 8.8%, p = 0.008) and maximal effort (VO2MAX; 15.8% vs. 8.0%, p = 0.036), as well as tolerance time (TT) to reach anaerobic threshold (TTAT; 62.0 vs. 37.7, p = 0.048), TTRCP (49.3 vs. 32.9, p = 0.032), and TTMAX (38.9 vs. 29.2, p = 0.042). Exercise intensity was an important factor in improving HR recovery and CRF of FH+women. These findings may have important implications for designing exercise-training programmes for the prevention of an inherited hypertensive disorder.

scholarly journals Limitations of skeletal muscle oxygen delivery and utilization during moderate-intensity exercise in moderately impaired patients with chronic heart failure

2016 ◽  
Vol 311 (6) ◽  
pp. H1530-H1539 ◽  
Author(s):  
Victor M. Niemeijer ◽  
Ruud F. Spee ◽  
Thijs Schoots ◽  
Pieter F. F. Wijn ◽  
Hareld M. C. Kemps
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Chronic Heart Failure ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Oxygen Uptake Kinetics ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Exercise Tests ◽  
Mean Response Time

The extent and speed of transient skeletal muscle deoxygenation during exercise onset in patients with chronic heart failure (CHF) are related to impairments of local O2 delivery and utilization. This study examined the physiological background of submaximal exercise performance in 19 moderately impaired patients with CHF (Weber class A, B, and C) compared with 19 matched healthy control (HC) subjects by measuring skeletal muscle oxygenation (SmO2) changes during cycling exercise. All subjects performed two subsequent moderate-intensity 6-min exercise tests (bouts 1 and 2) with measurements of pulmonary oxygen uptake kinetics and SmO2 using near-infrared spatially resolved spectroscopy at the vastus lateralis for determination of absolute oxygenation values, amplitudes, kinetics (mean response time for onset), and deoxygenation overshoot characteristics. In CHF, deoxygenation kinetics were slower compared with HC (21.3 ± 5.3 s vs. 16.7 ± 4.4 s, P < 0.05, respectively). After priming exercise (i.e., during bout 2), deoxygenation kinetics were accelerated in CHF to values no longer different from HC (16.9 ± 4.6 s vs. 15.4 ± 4.2 s, P = 0.35). However, priming did not speed deoxygenation kinetics in CHF subjects with a deoxygenation overshoot, whereas it did reduce the incidence of the overshoot in this specific group ( P < 0.05). These results provide evidence for heterogeneity with respect to limitations of O2 delivery and utilization during moderate-intensity exercise in patients with CHF, with slowed deoxygenation kinetics indicating a predominant O2 utilization impairment and the presence of a deoxygenation overshoot, with a reduction after priming in a subgroup, indicating an initial O2 delivery to utilization mismatch.

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