Changes in sympathoadrenal response to standing in humans after spaceflight

1995 ◽  
Vol 79 (2) ◽  
pp. 428-433 ◽  
Author(s):  
P. A. Whitson ◽  
J. B. Charles ◽  
W. J. Williams ◽  
N. M. Cintron
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Stroke Volume ◽  
Space Shuttle ◽  
Cardiovascular Responses ◽  
Plasma Norepinephrine ◽  
Plasma Catecholamine ◽  
Blood Samples ◽  
Before And After ◽  
Catecholamine Levels

Plasma catecholamine levels and cardiovascular responses to standing were determined in astronauts before and after several Space Shuttle missions. Blood pressure, heart rate, and cardiac output were measured and blood samples for catecholamine analyses were drawn at the end of the supine and standing periods. Supine plasma norepinephrine and epinephrine concentrations increased 34 and 65%, respectively, on landing day compared with before flight. Standing on landing day resulted in a 65 and 91% increase in plasma norepinephrine and epinephrine, respectively. Supine and standing norepinephrine levels remained elevated 3 days after landing while epinephrine levels returned to preflight levels. On landing day, supine heart rate and systolic blood pressure increased 18 and 8.9%, respectively, and standing heart rate and diastolic blood pressure were elevated by 38 and 19%, respectively. On standing, stroke volume was decreased by 26% on landing day compared with before flight. Collectively, these data indicate that the decreased orthostatic function after spaceflight results largely from the decreased stroke volume. Possible mechanisms contributing to this condition are discussed.

Cardiovascular and norepinephrine responses of men and women to two cold pressor tests

1992 ◽  
Vol 70 (1) ◽  
pp. 36-42 ◽  
Author(s):  
J. K. McLean ◽  
P. Sathasivam ◽  
K. MacNaughton ◽  
T. E. Graham
Keyword(s):  
Blood Pressure ◽  
Gender Differences ◽  
Heart Rate ◽  
Latin Square ◽  
Cold Pressor ◽  
Plasma Norepinephrine ◽  
Plasma Catecholamine ◽  
The Face ◽  
Blood Pressure Responses ◽  
Venous Plasma

Two types of cold pressor tests were used to study gender differences in cardiovascular and plasma catecholamine responses. Ten male and ten female, young, healthy Caucasian subjects participated. The tests consisted of (1) 5 °C air blown at 3.5–4 m/s onto part of the face for 4 min and (2) the open right hand immersed to the wrist in water at 5 °C for 4 min. Heart rate, blood pressure (BP), and venous plasma norepinephrine were collected before, during, and 5 min after the 4 min of cold exposures. Test order was decided by a Latin square design, and the subjects rested in a quiet room for 30 min between the two tests. All parameters demonstrated significant (p < 0.01) increases from rest during the cold tests. Gender differences were significant (p < 0.01) in diastolic and systolic BP in each test with the males having a greater response, but gender differences were not found in heart rate or norepinephrine concentration. The study demonstrated that gender differences exist in the blood pressure responses to local cold, but that the mechanisms involved do not include a parallel difference in heart rate or venous plasma norepinephrine concentration.Key words: blood pressure, gender differences, stroke volume.

Orthostatic intolerance after spaceflight

1996 ◽  
Vol 81 (1) ◽  
pp. 7-18 ◽  
Author(s):  
J. C. Buckey ◽  
L. D. Lane ◽  
B. D. Levine ◽  
D. E. Watenpaugh ◽  
S. J. Wright ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Space Shuttle ◽  
Orthostatic Intolerance ◽  
Peripheral Resistance ◽  
Systemic Hemodynamic ◽  
Vasoconstrictor Response ◽  
Before And After ◽  
Underlying Mechanisms

Orthostatic intolerance occurs commonly after spaceflight, and important aspects of the underlying mechanisms remain unclear. We studied 14 individuals supine and standing before and after three space shuttle missions of 9-14 days. After spaceflight, 9 of the 14 (64%) crew members could not complete a 10-min stand test that all completed preflight. Pre- and postflight supine hemodynamics were similar in both groups except for slightly higher systolic and mean arterial pressures preflight in the finishers [15 +/- 3.7 and 8 +/- 1.2 (SE) mmHg, respectively; P < 0.05]. Postflight, finishers and nonfinishers had equally large postural reductions in stroke volume (-47 +/- 3.7 and -48 +/- 3.3 ml, respectively) and increases in heart rate (35 +/- 6.6 and 51 +/- 5.2 beats/min, respectively). Cardiac output during standing was also similar (3.6 +/- 0.4 and 4.1 +/- 0.3 l/min, respectively). However, the finishers had a greater postflight vasoconstrictor response with higher total peripheral resistance during standing (22.3 +/- 1.2 units preflight and 29.4 +/- 2.3 units postflight) than did the nonfinishers (20.1 +/- 1.1 units preflight and 19.9 +/- 1.4 units postflight). We conclude that 1) the primary systemic hemodynamic event, i.e., the postural decrease in stroke volume, was similar in finishers and nonfinishers and 2) the heart rate response and cardiac output during standing were not significantly different, but 3) the postural vasoconstrictor response was significantly greater among the finishers (P < 0.01).

Blood pressure and plasma catecholamines in acute and prolonged hypoxia: effects of local hypothermia

1999 ◽  
Vol 87 (6) ◽  
pp. 2053-2058 ◽  
Author(s):  
Inge-Lis Kanstrup ◽  
Troels Dirch Poulsen ◽  
Jesper Melchior Hansen ◽  
Lars Juel Andersen ◽  
Morten Heiberg Bestle ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Sea Level ◽  
High Pressures ◽  
Acute Mountain Sickness ◽  
Plasma Catecholamines ◽  
Plasma Norepinephrine ◽  
Plasma Catecholamine ◽  
Local Cooling ◽  
Local Hypothermia

This study measured the pressor and plasma catecholamine response to local hypothermia during adaptation to hypobaric hypoxia. Eight healthy men were studied at rest and after 10 and 45 min of local cooling of one hand and forearm as well as after 30 min of rewarming at sea level and again 24 h and 5 days after rapid, passive transport to high altitude (4,559 m). Acute mountain sickness scores ranged from 5 to 16 (maximal attainable score: 20) on the first day but were reduced to 0–8 by the fifth day. Systolic blood pressure, heart rate, and plasma epinephrine increased on day 1 at altitude compared with sea level but declined again on day 5, whereas diastolic and mean blood pressures continued to rise in parallel with plasma norepinephrine. With local cooling, an increased vasoactive response was seen on the fifth day at altitude. Very high pressures were obtained, and the pressure elevation was prolonged. Heart rate increased twice as much on day 5 compared with the other two occasions. Thoracic fluid index increased with cooling on day 5, suggesting an increase in pulmonary vascular resistance. In conclusion, prolonged hypoxia seems to elicit an augmented pressor response to local cooling in the systemic and most likely also the pulmonary circulation.

scholarly journals Reduced GABA inhibition of sympathetic function in renal-wrapped hypertensive rats

1998 ◽  
Vol 275 (5) ◽  
pp. R1523-R1529 ◽  
Author(s):  
Douglas S. Martin ◽  
Joseph R. Haywood
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Pressure ◽  
Paraventricular Nucleus ◽  
Plasma Norepinephrine ◽  
Plasma Catecholamine ◽  
Hypertensive Rats ◽  
Sympathetic Function ◽  
Arterial Pressure Measurement ◽  
Gaba Function

Animals with bilateral cannulas in the paraventricular nucleus were made hypertensive by a one-kidney, figure eight renal wrap procedure or sham operated. Femoral artery and vein catheters were inserted for arterial pressure measurement and plasma catecholamine determination. After recovery and 4 days after hypertension surgery, bicuculline methiodide or muscimol was microinjected into the paraventricular nucleus. In some rats, nitroprusside was infused intravenously to reflexly stimulate the sympathetic nervous system. In control rats, bicuculline increased blood pressure, heart rate, and plasma norepinephrine and epinephrine concentrations. In contrast, in hypertensive rats blood pressure did not change while the heart rate response was maintained. Plasma norepinephrine and epinephrine responses were reduced 75 and 68%, respectively. Muscimol injections decreased arterial pressure in the hypertensive rats. Heart rate responses to nitroprusside were similar in the two groups of rats, while the plasma catecholamine responses were attenuated in the hypertensive animals. These data suggest that GABA function in the paraventricular nucleus is reduced in renal wrap hypertension.

Hemodynamic and Catecholamine Responses to Laryngoscopy and Tracheal Intubation in Patients with Complete Spinal Cord Injuries

2001 ◽  
Vol 95 (3) ◽  
pp. 647-651 ◽  
Author(s):  
Kyung Y. Yoo ◽  
JongUn Lee ◽  
Hak S. Kim ◽  
Woong M. Im
Keyword(s):  
Blood Pressure ◽  
Spinal Cord ◽  
Heart Rate ◽  
Tracheal Intubation ◽  
Endotracheal Intubation ◽  
Spinal Cord Injuries ◽  
Plasma Concentrations ◽  
Cardiovascular Responses ◽  
Plasma Catecholamine ◽  
Cord Injury

Background Endotracheal intubation in patients undergoing general anesthesia often causes hypertension and tachycardia, which may be altered when the efferent sympathetic fiber to the cardiovascular system is interrupted. The aim of the current study was to investigate the effects of different levels of spinal cord injury on the cardiovascular responses to intubation. Methods Fifty-four patients with traumatic complete cord injuries requiring tracheal intubation were grouped into quadriplegics (above C7; n = 22), high paraplegics (T1-T4, n = 8), and low paraplegics (below T5, n = 24) according to the level of injury. Twenty patients without spinal injury served as controls. Arterial pressure, heart rate, and rhythm were recorded at intervals for up to 5 min after intubation. Plasma concentrations of catecholamines were also measured. Results The intubation increased the systolic blood pressure similarly in control, high-paraplegic, and low-paraplegic groups (P &lt; 0.05), whereas it did not alter the blood pressure in the quadriplegic group. Heart rate was significantly increased in all groups; however, the magnitude was more pronounced in the high-paraplegic group (67%) than in the control (38%) and quadriplegic (33%) groups. Plasma concentrations of norepinephrine were significantly increased after intubation in all groups; however, values were lower in the quadriplegic group and higher in the low-paraplegic group compared with those in the control group. Incidence of arrhythmias did not differ among groups. Conclusions The cardiovascular and plasma catecholamine changes associated with endotracheal intubation may differ according to the affected level in patients with complete spinal cord injuries.

Area postrema-induced inhibition of the exercise pressor reflex

1997 ◽  
Vol 272 (4) ◽  
pp. H1650-H1655 ◽  
Author(s):  
S. Bonigut ◽  
A. C. Bonham ◽  
C. L. Stebbins
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Area Postrema ◽  
Cardiovascular Responses ◽  
Thermal Lesion ◽  
Thermal Coagulation ◽  
Exercise Pressor Reflex ◽  
Before And After ◽  
Chemical Lesion ◽  
Pressor Reflex

The exercise pressor reflex is opposed by the arterial baroreflex, and circulating peptides may act in the area postrema to enhance this inhibition. Therefore, we tested the hypothesis that the area postrema exerts an inhibitory effect on this reflex. Consequently, in six alpha-chloralose-anesthetized cats, blood pressure and heart rate responses to 30 s of electrically stimulated hindlimb contraction were compared before and after thermal coagulation of the area postrema. In six other cats, the same contraction-induced cardiovascular responses were assessed before and after chemical lesion of the area postrema using kainic acid (214 +/- 9 nl, 2.5-5 mM). Thermal lesion of the area postrema augmented blood pressure and heart rate responses to contraction from 29 +/- 5 to 47 +/- 7 mmHg (P < 0.05) and from 8 +/- 2 to 14 +/- 2 beats/min (P < 0.05), respectively. Chemical lesion of the area postrema enhanced contraction-evoked blood pressure (30 +/- 7 vs. 47 +/- 6 mmHg, P < 0.05) and heart rate (12 +/- 4 vs. 17 +/- 4 beats/min, P < 0.05) responses. These data suggest that the area postrema attenuates the exercise pressor reflex, possibly through the actions of circulating peptides on baroreflex function.

Cardiovascular responses of heart transplant patients to exercise training

1991 ◽  
Vol 70 (6) ◽  
pp. 2627-2631 ◽  
Author(s):  
S. Keteyian ◽  
R. Shepard ◽  
J. Ehrman ◽  
F. Fedel ◽  
C. Glick ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Exercise Training ◽  
Comparison Group ◽  
Cardiovascular Responses ◽  
Orthotopic Heart Transplantation ◽  
O2 Consumption ◽  
Peak Heart Rate ◽  
Exercise Tests ◽  
Before And After

Orthotopic heart transplantation (OHT) represents an effective alternative for individuals with end-stage heart disease. The current literature reports only the responses of OHT patients to greater than or equal to 4 mo of exercise training (ET) and frequently lacks adequate controls. Most programs currently treating OHT patients usually provide 6-12 wk of ET. This study describes the effects of a 10-wk supervised ET program in 12 male OHT patients and 5 other male OHT patients who served as a comparison group. Graded exercise tests were performed before and after ET. After ET, maximal O2 consumption was significantly greater for the ET group than the comparison group (P less than 0.05) and the mean increase in peak heart rate was 18 +/- 4 and 6 +/- 4 (SE) min-1 for ET and comparison groups, respectively (P less than 0.05). Maximal ventilation was also significantly greater for the ET group at after ET, while resting heart rate and blood pressure and peak blood pressure, O2 pulse, respiratory rate, and ventilatory equivalents for O2 and CO2 were not significantly changed. We conclude that after OHT a 10-wk ET program improves maximal O2 consumption and, by improving peak heart rate, improves O2 delivery.

scholarly journals Cardiovascular Responses, Physical Activity Intensity, and Enjoyment Level of Nintendo Switch™ Exergaming, Comparing Different Tempos and Playing Modes: A Pilot Study

2021 ◽  
Vol 3 (2) ◽  
pp. 44
Author(s):  
Bayu Aji Mayogya Putra ◽  
Reni Hendrarati Masduchi ◽  
Martha Kurnia Kusumawardani
Keyword(s):  
Physical Activity ◽  
Blood Pressure ◽  
Heart Rate ◽  
Perceived Exertion ◽  
Cardiovascular Responses ◽  
Rating Of Perceived Exertion ◽  
Physical Activity Intensity ◽  
Activity Intensity ◽  
Before And After ◽  
Rate Sensor

Background: Physical activity (PA) has been associated with multiple health benefits. However, the global population does not meet the PA recommendations. Virtual reality exergaming (VR EXG) can become an option to increase PA because it is fun, relatively easy to access and affordable through popular commercial devices.Aim: To investigate the immediate cardiovascular responses(blood pressure, heart rate), quantification of PA intensity(percentage of maximum heart rate (%HRmax), Borg’s rating of perceived exertion (RPE), and the level of enjoyment using visual analog scale (VAS) while playing VR EXG.Material and Methods: Fifteen healthy men (aged 31.87±3.14 years old, body mass index 23.77±2.47 kg/m2) undergone three“Fitness Boxing” Nintendo Switch™ playing modes in the same order: (1) single player-normal tempo, (2) single player-fast tempo and (3) versus. During playing, participant’s HR was monitored using Polar H10 heart rate sensor. Blood pressure was measured before and after playing. Borg’s RPE and VAS were collected after playing.Results: Our results showed significant heart rate and systolic blood pressure increase (p = 0.001) in all three playing conditions, whereas diastolic blood pressure was relatively constant (p > 0.05). The Borg’s RPE were in 12-13 range (moderate) and %HRmax range between 72- 81% (vigorous). The enjoyment level was found greatest in versus mode compared to other playing modes.Conclusion: VR EXG Nintendo Switch™ “Fitness Boxing” can elicit immediate cardiovascular responses and provides an enjoyable moderate to vigorous PA intensity in healthy male adults, and can be used to meet the weekly PA recommendations. 

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