scholarly journals Moderate Exercise Based on Artificial Gravity Preserves Orthostatic Tolerance and Exercise Capacity During Short-Term Head-Down Bed Rest

2017 ◽  
pp. 567-580 ◽  
Author(s):  
X.-T. LI ◽  
C.-B. YANG ◽  
Y.-S. ZHU ◽  
J. SUN ◽  
F. SHI ◽  
...  
Keyword(s):  
Aerobic Exercise ◽  
Plasma Volume ◽  
Systolic Function ◽  
Bed Rest ◽  
Control Group ◽  
Orthostatic Tolerance ◽  
Short Term ◽  
Exercise Endurance ◽  
Physical Deconditioning ◽  
Cardiac Systolic Function

Numerous countermeasures have been proposed to minimize microgravity-induced physical deconditioning, but their benefits are limited. The present study aimed to investigate whether personalized aerobic exercise based on artificial gravity (AG) mitigates multisystem physical deconditioning. Fourteen men were assigned to the control group (n=6) and the countermeasure group (CM, n=8). Subjects in the CM group were exposed to AG (2 Gz at foot level) for 30 min twice daily, during which time cycling exercise of 80-95 % anaerobic threshold (AT) intensity was undertaken. Orthostatic tolerance (OT), exercise tests, and blood assays were determined before and after 4 days head-down bed rest (HDBR). Cardiac systolic function was measured every day. After HDBR, OT decreased to 50.9 % and 77.5 % of pre-HDBR values in control and CM groups, respectively. Exercise endurance, maximal oxygen consumption, and AT decreased to 96.5 %, 91.5 % and 91.8 % of pre-HDBR values, respectively, in the control group. Nevertheless, there were slight changes in the CM group. HDBR increased heart rate, sympathetic activity, and the pre-ejection period, but decreased plasma volume, parasympathetic activity and left-ventricular ejection time in the control group, whereas these effects were eliminated in the CM group. Aldosterone had no change in the control group but increased significantly in the CM group. Our study shows that 80-95 % AT aerobic exercise based on 2 Gz of AG preserves OT and exercise endurance, and affects body fluid regulation during short-term HDBR. The underlying mechanisms might involve maintained cardiac systolic function, preserved plasma volume, and improved sympathetic responses to orthostatic stress.

scholarly journals Effect of intermittent hypoxic training on orthostatic tolerance in humans before and after simulated microgravity

2020 ◽  
Author(s):  
VP Katuntsev ◽  
TV Sukhostavtseva ◽  
AN Kotov ◽  
MV Baranov
Keyword(s):  
Orthostatic Intolerance ◽  
Bed Rest ◽  
Daily Basis ◽  
Tilt Test ◽  
Control Group ◽  
Orthostatic Tolerance ◽  
Pronounced Increase ◽  
Intermittent Hypoxic Training ◽  
Hypoxic Training ◽  
Before And After

Reduced orthostatic tolerance (OT) is a serious concern facing space medicine. This work sought to evaluate the effects of intermittent hypoxic training (IHT) on OT in humans before and after 3 days of head-down bed rest (HDBR) used to model microgravity. The study was carried out in 16 male volunteers aged 18 to 40 years and included 2 series of experiments with 11-day and 21-day IHT administered on a daily basis. During the first IHT session, the concentration of oxygen in the inspired gas mixture was 10%; for other sessions it was adjusted to 9%. OT was assessed by a 20-minute-long orthostatic tilt test (OTT) conducted before and after HDBR. Before HDBR, orthostatic intolerance was observed in 3 participants, while after HDBR, it was observed in 9 of 16 volunteers (p < 0.05). During OTT conducted after HDBR, the heart rate (HR) exceeded control values by 26.8% (p < 0.01). Preexposure to any of the applied IHT regimens led to a reduction in the number of volunteers with orthostatic intolerance. After the 11-day IHT program, there was a less pronounced increase in HR during OTT before HDBR; with the extended IHT regimen, less pronounced changes were observed for HR, systolic, diastolic and mean blood pressure (BP). The increase in HR during OTT after HDBR was significantly lower in the group that had completed the 11-day IHT program, while BP remained stable. The changes in HR and systolic BP were less pronounced in the group that had completed the 21-day IHT program than in the control group (p < 0.05). Thus, IHT reduced the risk of orthostatic disorders and mitigated changes in cardiovascular parameters during the orthostatic test.

scholarly journals Transcutaneous Electrical Acupuncture Stimulation as a Countermeasure against Cardiovascular Deconditioning during 4 days of Head-Down Bed Rest in Humans

2015 ◽  
Vol 33 (5) ◽  
pp. 381-387 ◽  
Author(s):  
Jing Sun ◽  
Xiaotao Li ◽  
Changbin Yang ◽  
Yongchun Wang ◽  
Fei Shi ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Plasma Volume ◽  
Bed Rest ◽  
Control Group ◽  
Acupuncture Stimulation ◽  
Cardiovascular Deconditioning ◽  
Electrical Acupuncture ◽  
Before And After ◽  
Registration Number ◽  
Plasma Hormones

Objective Spaceflight is associated with cardiovascular deregulation. However, the influence of microgravity on the cardiovascular system and its mechanisms and countermeasures remain unknown. Our previous studies have demonstrated that transcutaneous electrical acupuncture stimulation (TEAS) is effective in improving orthostatic tolerance (OT). The purpose of this study was to determine if TEAS treatment can attenuate cardiovascular deconditioning induced by a 4-day −6° head-down bed rest (HDBR). Methods Fourteen healthy male subjects were randomly allocated to a control group (control, n=6, 4 days HDBR without countermeasures) and a TEAS treatment group (TEAS, n=8, 4 days HDBR with TEAS at Neiguan (PC6) for 30 min each day for 4 consecutive days during HDBR). OT, plasma hormones, plasma volume and heart rate variability were assessed before and after HDBR. Cardiac function and cerebral blood flow were measured before, during and after HDBR. Results The data showed that TEAS treatment mitigated the decrease in OT that was observed in the control group and cardiac function, alleviated autonomic dysfunction, and partially prevented plasma volume reduction after HDBR. Angiotensin II and aldosterone were significantly increased by 129.3% and 133.3% after HDBR in the TEAS group (p<0.05). Conclusions These results indicate that 30 min of daily TEAS treatment at PC6 is partially effective in maintaining OT, probably due to increased plasma volume-regulating hormones and activation of the peripheral sympathetic nervous system. TEAS treatment appears effective at reducing cardiovascular deconditioning induced by HDBR for 4 days. Trial Registration Number NCT02300207.

scholarly journals OR-052 Effects of Exercise Intervention on Cancer-Related Fatigue in Breast Cancer Survivors

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Zhiling Xie ◽  
Weibing Ye
Keyword(s):  
Breast Cancer ◽  
Cancer Survivors ◽  
Aerobic Exercise ◽  
Breast Cancer Survivors ◽  
Exercise Intervention ◽  
Moderate Intensity ◽  
Control Group ◽  
Short Term ◽  
Cancer Related Fatigue ◽  
Significant Difference

Objective cancer-related fatigue(CRF) is the most commonly reported and most distressing symptom in cancer patient.The purpose of this study was to review the effect of exercise intervention on cancer-related fatigue in breast cancer survivors. Methods From 1998 to 2018 in Chinese and English literature of Wanfang Database, Pubmed, SportDiscus and Springer databases, picked out the randomized controlled trials which up to standard. Keywords cancer, exercise, fatigue, etc. were used for systematic search and tracking. 12 experiments were reviewed to analyze the effect differences between exercise intervention and exercise-related fatigue. Results Most interventions use aerobic exercise as the primary form of exercise. Generally, exercise interventions are effective for cancer-related fatigue, but some findings are not. Many studies have shown that moderate intensity aerobic exercise has a significant effect on cancer-related fatigue, with 50-70% heart rate reserve and 3-5 times of exercise per week for at least 30 minutes each time. Exercise methods mainly include walking, yoga, cycling and tai chi. Firstly, Supervised aerobic exercise was statistically more effective than conventional care in improving CRF among breast cancer survivors. It has been shown that group-based, supervised exercise produces positive psychosocial‘side-effects’ due to social interactions, improved self-efficacy, and attention from a trainer. Secondly, Cancer fatigue is divided into acute and chronic fatigue, 18 weeks of exercise intervention can reduce the short-term fatigue, at 36 weeks, baseline levels of fatigue index responses and contrast on the issue of the multivariate statistics. Thirdly, usual-care group were reported that they had been actively engaged in regular exercise before study enrollment. During the exercise intervention, most studies on the control ways are according to the daily life or to take care of, but studies have reported, before intervention, to a high level of 40% in the control group often exercise, exercise also as usual during the intervention, which causes the control to the baseline level is higher, but the intervention group and control group will be difference, no significant difference, lead to the result is invalid. Conclusions First, the exercise intervention of cancer-related fatigue needs to be supervised; second, the exercise intervention is effective for short-term cancer-related fatigue; third, the daily exercise level of the control group will affect the intervention effect.

Effectiveness of Aerobic Exercise on Smoking Cessation in Adults: A Systematic Review and Meta-Analysis

2021 ◽  
Vol 18 (2) ◽  
pp. 230-242
Author(s):  
Caroline Pereira Santos ◽  
Mahara Proença ◽  
Tamara dos Santos Gouveia ◽  
Crystian Bitencourt Soares de Oliveira ◽  
Guilherme Yassuki Tacao ◽  
...  
Keyword(s):  
Systematic Review ◽  
Smoking Cessation ◽  
Aerobic Exercise ◽  
Usual Care ◽  
Meta Analysis ◽  
Control Group ◽  
Short Term ◽  
Continuous Abstinence ◽  
Different Characteristics

Background: The specific benefits of aerobic exercises in smoking cessation are unclear, as they have different characteristics, intensities, and durations. The purpose of this systematic review with meta-analysis was to evaluate the effects of aerobic exercise, with or without co-interventions, compared with a control group of cognitive behavior treatment on smoking cessation. Methods: This review was prospectively registered on PROSPERO, and the searches were performed from 2016 to 2018. Randomized controlled trials evaluating the effects of aerobic exercise, with or without nicotine therapy replacement, compared with usual care were included. The primary outcome was smoking cessation defined as the prevalence of those who quit or continuous abstinence. Meta-analysis was calculated using random effects model in the comprehensive meta-analysis software. Results: The authors identified 18 trials reporting data for a total of 2815 participants. There was moderate-quality evidence that aerobic exercise was better than usual care in promoting smoking cessation at short term (11 trials, risk ratio 0.79; 95% confidence interval, 0.66–0.94). However, there were no differences between aerobic exercises and usual care at medium- or long-term follow-ups. Conclusions: According to review, aerobic exercise may be effective in promoting smoking cessation at short-term, but not at medium- and long-term follow-ups.

scholarly journals Lower-body negative pressure/ergometer exercise in bed rest: Effects on female orthostatic tolerance

2020 ◽  
Vol 4 (2) ◽  
pp. 040-048
Author(s):  
Wang Linjie ◽  
Li Zhili ◽  
Tan Cheng ◽  
Wang Huijuan ◽  
Zhou Xiangjie ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Orthostatic Intolerance ◽  
Lower Body Negative Pressure ◽  
Bed Rest ◽  
Tilt Test ◽  
Control Group ◽  
Orthostatic Tolerance ◽  
Lower Body ◽  
Interval Exercise ◽  
Ergometer Exercise

Introduction: Alternatively using gradient lower-body negative pressure (LBNP) and ergometer exercise (LBNP + ergo) under a flight schedule framework was explored to detect its orthostatic capacity maintenance effects in female subjects after 15 days of -6° head-down bed rest (HDBR). Methods: Twenty-two female university students were divided into a control group (n = 8), an LBNP group (n = 7), and an LBNP + ergo group (n = 7). Ergometer exercise consisted of an interval exercise protocol with 2 min intervals alternating between 41% and 70% VO2max. Gradient LBNP was decompressed in 10 mm Hg intervals to -40 mmHg every 5 min. intermittent ergometer exercise and LBNP were alternatively performed. Tilt test was performed 2 days before HDBR (R-2), on the day of HDBR termination (R+1), and 5 days after HDBR (R+5). Results: Fifty percent of the participants (11/22) did not pass the tilt test on R+1. The orthostatic tolerance time decreased from 20 to 16.1 ± 2.1 min in the control group, to 10.0 ± 2.7 min in the LBNP group (p = 0.01) and to 16.3 ± 2.0 min in the LBNP + ergo group. The HRs and BPs were at similar level among three groups during tilt test on different test days. Compared with the control group, the LBNP + ergo group had higher SV and CO percentage changes at R+1(p < 0.023) and R+5 (p < 0.00001) during the tilt test. Conclusion: LBNP combined with ergometer exercises fails to prevent orthostatic intolerance but it induced some positive hemodynamic changes during tilt test after 15 days HDBR.

Abstract P192: Orthostatic Tolerance Before And After 60 Days Of Strict Head Down Tilt Bedrest With And Without Daily Artificial Gravity Training

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Jan Hoenemann ◽  
Fabian Hoffmann ◽  
Stefan Moestl ◽  
Karten Heusser ◽  
Edwin Mulder ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Plasma Volume ◽  
Orthostatic Intolerance ◽  
Lower Body Negative Pressure ◽  
Cardiovascular Responses ◽  
Pooled Analysis ◽  
Artificial Gravity ◽  
Control Group ◽  
Orthostatic Tolerance ◽  
Before And After

Background: Orthostatic intolerance occurs after space flight, immobilization and in patients with autonomic diseases, so there is a need for more effective countermeasures. We hypothesized that daily artificial gravity elicited through short-arm centrifugation attenuates plasma volume loss and orthostatic intolerance following 60 days of HDTBR, which models cardiovascular responses to weightlessness. Methods: We studied 24 healthy persons (8 women, 33.4±9.3 yr, 24.3±2.1 kg/m2) exposed to 60d HDTBR. Subjects were assigned to 30 min/d continuous short arm centrifugation (cAG), 6x5 min short arm centrifugation (iAG), or a control group (ctr, no countermeasures). Head-up tilt testing (15 min of 80°) followed by incremental lower body negative pressure (-10 mmHg every 3 min) until presyncope was performed before and at the end of HDTBR. Plasma volume was measured (CO rebreathing) 12-2 days before and after 56d of HDTBR. Stroke volume was measured by cMRI. Norepinephrine, epinephrine, aldosterone, and renine plasma levels were measured before and after HDTBR. Results: Time to presyncope decreased in all groups following bedrest (ctr: 22:56 min pre and 9:35 min post, cAG 15:34 min pre and 10:11 min post; iAG 14:56 min pre and 10:00 min post, p<0.001). The significant interaction (p=0.025) between bedrest and intervention was explained by greater baseline orthostatic tolerance time in the ctr. AG Data was pooled analysis. The reduction in stroke volume (ctr, pre: 93±19 ml, HDTBR: 69±13 ml, AG, pre: 88±20 ml, HDTBR: 67±17 ml) and plasma volume was similar (ctr, pre: 4155±1085 ml, HDTBR: 3855±1087 ml, AG, pre: 4114±1250 ml, HDTBR: 3674± 1313 ml). Catechols and aldosterone did not change significantly during bedrest. The increase in renine was similar between groups (ctr pre: 18±12 mE/L, HDTBR: 21±8 mE/L, AG pre: 21±10 mE/L, HDTBR: 31±12 mE/L). Conclusions: 30 min daily AG didn’t prevent a reduction in orthostatic tolerance following 60d HDTBR. Whether numerically smaller reductions in orthostatic tolerance in the AG groups indicate efficacy or result from baseline differences can’t be ascertained. A stronger AG stimulus or combination with other countermeasures might be required to maintain orthostatic tolerance and to attenuate the volume reduction.

Exercise plus volume loading prevents orthostatic intolerance but not reduction in cerebral blood flow velocity after bed rest

2012 ◽  
Vol 302 (2) ◽  
pp. H489-H497 ◽  
Author(s):  
Sung-Moon Jeong ◽  
Shigeki Shibata ◽  
Benjamin D. Levine ◽  
Rong Zhang
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Blood Flow Velocity ◽  
Orthostatic Intolerance ◽  
Bed Rest ◽  
Left Ventricular ◽  
Stress Index ◽  
Control Group ◽  
Orthostatic Tolerance ◽  
Volume Loading

This study tested the hypothesis that reduction in cerebral blood flow (CBF) during orthostatic stress after bed rest can be ameliorated with volume loading, exercise, or both. Transcranial Doppler was used to measure changes in CBF velocity during lower body negative pressure (LBNP) before and after an 18-day bed rest in 33 healthy subjects. Subjects were assigned into four groups with similar age and sex: 1) supine cycling during bed rest (Exercise group; n = 7), 2) volume loading with Dextran infusion after bed rest to restore reduced left ventricular filling pressure (Dextran group; n = 7), 3) exercise combined with volume loading to prevent orthostatic intolerance (Ex-Dex group; n = 7), and 4) a control group ( n = 12). LBNP tolerance was measured using a cumulative stress index (CSI). After bed rest, CBF velocity was reduced at a lower level of LBNP in the Control group, and the magnitude of reduction was greater in the Ex-Dex group. However, reduction in orthostatic tolerance was prevented in the Ex-Dex group. Notably, volume loading alone prevented greater reductions in CBF velocity after bed rest, but CSI was reduced still by 25%. Finally, decreases in CBF velocity during LBNP were correlated with reduction in cardiac output under all conditions ( r2 = 0.86; P = < 0.001). Taken together, these findings demonstrate that volume loading alone can ameliorate reductions in CBF during LBNP. However, the lack of associations between changes in CBF velocity and orthostatic tolerance suggests that reductions in CBF during LBNP under steady-state conditions by itself are unlikely to be a primary factor leading to orthostatic intolerance.

Effect of prolonged bed rest on lung volume in normal individuals

1986 ◽  
Vol 61 (3) ◽  
pp. 919-925 ◽  
Author(s):  
W. S. Beckett ◽  
N. B. Vroman ◽  
D. Nigro ◽  
S. Thompson-Gorman ◽  
J. E. Wilkerson ◽  
...  
Keyword(s):  
Plasma Volume ◽  
Measurement Techniques ◽  
Bed Rest ◽  
Control Group ◽  
Base Line ◽  
Lung Capacity ◽  
Exogenous Estrogen ◽  
Normal Individuals ◽  
Residual Capacity ◽  
Helium Dilution

Pulmonary function was assessed in supine subjects before, during, and after three separate bed-rest studies of 11 and 12 days duration. Forced vital capacity (FVC) increased during bed rest in each subject. Total lung capacity (TLC) was measured by helium dilution in one bed-rest study and increased in each subject, while residual volume and functional residual capacity of the respiratory system did not change. No change in FVC was found in an ambulatory control group using identical measurement techniques. Maintaining base-line plasma volume during one bed rest by the use of exogenous estrogen did not prevent an increase in FVC, and decreasing plasma volume with diuretics in ambulatory subjects to the same degree as seen in the bed rests did not cause an increase in FVC. We conclude that prolonged bed rest results in a small significant increase in TLC and that this change is not dependent on alterations in plasma volume.

scholarly journals Combined administration of nicorandil and atorvastatin in patients with acute myocardial infarction after coronary intervention, and its effect on postoperative cardiac systolic function

2021 ◽  
Vol 20 (11) ◽  
pp. 2425-2431
Author(s):  
Zhirui Sun ◽  
Yachao Zhang ◽  
Yanxiang Shen
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Adverse Reactions ◽  
Systolic Function ◽  
Blood Lipid ◽  
Coronary Intervention ◽  
Control Group ◽  
Study Group ◽  
Atorvastatin Calcium ◽  
Cardiac Systolic Function

Purpose: To study the effect of a combination of nicorandil and atorvastatin calcium in patients with acute myocardial infarction after coronary intervention, and its effect on postoperative cardiac systolic function of patients.Methods: Retrospective analysis was performed on 100 patients with acute myocardial infarctiontreated with coronary interventional therapy in The Third Affiliated Hospital of Qiqihaer MedicalUniversity from April 2019 to August 2020. The patients were randomised into control and study groups, with 50 patients in each group. The control group was treated with nicorandil, while the study group was treated with a combination of nicorandil and atorvastatin. Treatment response, cardiac structural indices, cardiac systolic function, blood lipid profiles, quality of life (QLI) score, Barthel Index (BI), Fugl- Meyer assessment (FMA), motor function score, incidence of adverse reactions, and blood pressure changes on days 1, 2, 3 and 4 after surgery, were compared between the two groups.Results: Treatment effectiveness, cardiac systolic function, QLI score, BI index and FMA motor function score in the study group were higher than the corresponding control values (p < 0.05). However, lower cardiac structure indices, blood lipid profiles and incidence of adverse reactions were greater in the study group than in the control group (p < 0.05). No significant disparity in blood pressure was found between the two groups on post-surgery days 1, 2, 3 and 4.Conclusion: The combination of nicorandil and atorvastatin calcium tablets produced better outcomes in patients with acute myocardial infarction after coronary intervention therapy; furthermore, the combination therapy significantly improved the cardiac systolic function of patients.

Cardiac function during heat stress: impact of short-term passive heat acclimation

2020 ◽  
Vol 319 (4) ◽  
pp. H753-H764
Author(s):  
Lukas D. Trachsel ◽  
Hadiatou Barry ◽  
Hugo Gravel ◽  
Parya Behzadi ◽  
Christine Henri ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Cardiac Function ◽  
Systolic Function ◽  
Heat Exposure ◽  
Heat Acclimation ◽  
Passive Heating ◽  
Lower Heart Rate ◽  
Short Term ◽  
Cardiac Systolic Function

A lower heart rate during heat exposure is a classic marker of heat acclimation (HA). It remains unknown if improved cardiac function contributes to this response. A 7-day passive HA protocol did not alter cardiac systolic function during passive heating, whereas it improved some indexes of diastolic function in young adults. Nonetheless, heart rate during heating was unaffected by HA. These results suggest that passive HA induces limited adaptations in cardiac function during passive heating.

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