Combat and Blast Exposure Blunt Sympathetic Response to Acute Exercise Stress in Specialized Military Men

Elevated cardiorespiratory fitness improves resting cerebral perfusion, although to what extent this is further amplified during acute exposure to exercise stress and the corresponding implications for cerebral oxygenation remain unknown. To examine this, we recruited 12 moderately active and 12 sedentary healthy males. Middle cerebral artery blood velocity (MCAv) and prefrontal cortical oxyhemoglobin (cO2Hb) concentration were monitored continuously at rest and throughout an incremental cycling test to exhaustion. Despite a subtle elevation in the maximal oxygen uptake (active: 52 ± 9 ml/kg per minute versus sedentary: 33 ± 5 ml/kg per minute, P < 0.05), resting MCAv was not different between groups. However, more marked increases in both MCAv (+28 ± 13% versus +18 ± 6%, P < 0.05) and cO2Hb (+5 ±4% versus −2 ± 3%, P < 0.05) were observed in the active group during the transition from low- to moderate-intensity exercise. Collectively, these findings indicate that the long-term benefits associated with moderate increase in physical activity are not observed in the resting state and only become apparent when the cerebrovasculature is challenged by acute exertional stress. This has important clinical implications when assessing the true extent of cerebrovascular adaptation.

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Abstract P317: Acute Exercise Stress and ROS Signaling: Activation of Nrf2/ARE-Dependent Antioxidant Defense Mechanisms in the Mouse Myocardium

Circulation Research ◽

10.1161/res.109.suppl_1.ap317 ◽

2011 ◽

Vol 109 (suppl_1) ◽

Author(s):

Corey J Miller ◽

Kalavathy Ramachandran ◽

Gayatri D Khanderao ◽

Sankaranarayanan Kannan ◽

Vasanthi Rajasekaran ◽

...

Keyword(s):

Defense Mechanisms ◽

Acute Exercise ◽

Nuclear Translocation ◽

Ischemia Reperfusion ◽

Antioxidant Response ◽

Exercise Stress ◽

Related Factor ◽

Paramagnetic Resonance ◽

Antioxidant Genes ◽

Age Dependent

Background: Cellular defense mechanisms are crucial for maintaining intracellular redox state and mitigating free radical accumulation with aging. Nuclear Erythroid 2 p45 related factor-2 (Nrf2) regulates basal and inducible expression of numerous cytoprotective/antioxidant genes. We hypothesize that acute exercise will induce ROS, which triggers Nrf2/ARE signaling and promotes myocardial defense mechanisms. Methods: Age-matched wild-type (WT) and Nrf2−/− (KO) mice at 2 and >20 months were subjected to acute exercise stress (AES) and then we assessed the activation of Nrf2/ARE-dependent transcriptional mechanisms in the heart. Myocardial ROS was measured by electron paramagnetic resonance (EPR) analysis. Results: Under basal conditions, total ROS and GSH levels were identical at 2 months, whereas they were significantly impaired in Nrf2-KO when compared to Wt myocardium at ∼20 months indicating that Nrf2-deficiency is coupled with blemished redox potential. Upon AES, the young WT and KO mice exhibited oxidative stress (OS), but the WT were able compensate for the stress by increasing Nrf2 nuclear translocation and subsequent upregulation of cytoprotective genes. However, the aged (WT & KO) mice developed OS in response to AES. The degree of OS was several fold higher in the aged Nrf2-KO mice when compared with WT, suggesting an important age dependent function for Nrf2 in the myocardium. Western blot analysis revealed significant down regulation of major antioxidants (GCS, Nqo1, Ho1, catalase, G6pd and Gsr) in KO mice, while WT mice exhibited compensatory antioxidant response to the AES. Gene expression (qPCR) analysis revealed profound upregulation of major antioxidants in WT, but there was no such response occurred in KO mice after AES, suggesting Nrf2 independent mechanisms are inadequate to protect the myocardium. Conclusions: Acute exercise induces ROS and thereby activates Nrf2 in the myocardium. However, disruption of Nrf2 increases susceptibility of the myocardium to OS induced damage. Thus Nrf2 signaling might be a potential therapeutic target to protect the heart from ROS and/or age dependent ischemia/reperfusion (I/R) injury and myocardial infarction (MI).

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Platelet Reactivity in Diabetic Patients Subjected to Acute Exercise Stress Test

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000386327.04689.d7 ◽

2010 ◽

Vol 42 ◽

pp. 137

Author(s):

Mickey Scheinowitz ◽

Rajbabu Pakala ◽

Itsik Ben-Dor ◽

Sara D. Collins ◽

Soha Ahmad ◽

...

Keyword(s):

Acute Exercise ◽

Platelet Reactivity ◽

Stress Test ◽

Exercise Stress Test ◽

Exercise Stress ◽

Diabetic Patients

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Role of GDF15 in active lifestyle induced metabolic adaptations and acute exercise response in mice

Scientific Reports ◽

10.1038/s41598-019-56922-w ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Carla Igual Gil ◽

Mario Ost ◽

Juliane Kasch ◽

Sara Schumann ◽

Sarah Heider ◽

...

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Acute Exercise ◽

Treadmill Running ◽

Exercise Stress ◽

Metabolic Phenotype ◽

Obese Mice ◽

Active Lifestyle ◽

Post Exercise ◽

Stress Markers

AbstractPhysical activity is an important contributor to muscle adaptation and metabolic health. Growth differentiation factor 15 (GDF15) is established as cellular and nutritional stress-induced cytokine but its physiological role in response to active lifestyle or acute exercise is unknown. Here, we investigated the metabolic phenotype and circulating GDF15 levels in lean and obese male C57Bl/6J mice with long-term voluntary wheel running (VWR) intervention. Additionally, treadmill running capacity and exercise-induced muscle gene expression was examined in GDF15-ablated mice. Active lifestyle mimic via VWR improved treadmill running performance and, in obese mice, also metabolic phenotype. The post-exercise induction of skeletal muscle transcriptional stress markers was reduced by VWR. Skeletal muscle GDF15 gene expression was very low and only transiently increased post-exercise in sedentary but not in active mice. Plasma GDF15 levels were only marginally affected by chronic or acute exercise. In obese mice, VWR reduced GDF15 gene expression in different tissues but did not reverse elevated plasma GDF15. Genetic ablation of GDF15 had no effect on exercise performance but augmented the post exercise expression of transcriptional exercise stress markers (Atf3, Atf6, and Xbp1s) in skeletal muscle. We conclude that skeletal muscle does not contribute to circulating GDF15 in mice, but muscle GDF15 might play a protective role in the exercise stress response.

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Cardiac troponin T levels and exercise stress testing in patients with suspected coronary artery disease: the Akershus Cardiac Examination (ACE) 1 study

Clinical Science ◽

10.1042/cs20110557 ◽

2012 ◽

Vol 122 (12) ◽

pp. 599-606 ◽

Cited By ~ 35

Author(s):

Ragnhild Røysland ◽

Gunnhild Kravdal ◽

Arne Didrik Høiseth ◽

Ståle Nygård ◽

Pirouz Badr ◽

...

Keyword(s):

Myocardial Ischaemia ◽

Cardiac Troponin ◽

Stress Testing ◽

Acute Exercise ◽

Troponin T ◽

Suspected Coronary Artery Disease ◽

Exercise Stress ◽

Exercise Stress Testing ◽

Peak Exercise ◽

Post Exercise

Whether reversible ischaemia in patients referred for exercise stress testing and MPI (myocardial perfusion imaging) is associated with changes in circulating cTn (cardiac troponin) levels is controversial. We measured cTnT with a sensitive assay before, immediately after peak exercise and 1.5 and 4.5 h after exercise stress testing in 198 patients referred for MPI. In total, 19 patients were classified as having reversible myocardial ischaemia. cTnT levels were significantly higher in patients with reversible myocardial ischaemia on MPI at baseline, at peak exercise and after 1.5 h, but not at 4.5 h post-exercise. In patients with reversible ischaemia on MPI, cTnT levels did not change significantly after exercise stress testing [11.1 (5.2–14.9) ng/l at baseline compared with 10.5 (7.2–16.3) ng/l at 4.5 h post-exercise, P=0.27; values are medians (interquartile range)]. Conversely, cTnT levels increased significantly during testing in patients without reversible myocardial ischaemia [5.4 (3.0–9.0) ng/l at baseline compared with 7.5 (4.6–12.4) ng/l, P<0.001]. In conclusion, baseline cTnT levels are higher in patients with MPI evidence of reversible myocardial ischaemia than those without reversible ischaemia. However, although cTnT levels increase during exercise stress testing in patients without evidence of reversible ischaemia, this response appears to be blunted in patients with evidence of reversible ischaemia. Mechanisms other than reversible myocardial ischaemia may play a role for acute exercise-induced increases in circulating cTnT levels.

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Chronic inhibition of nitric oxide synthase augments the ACTH response to exercise

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.90709.2008 ◽

2009 ◽

Vol 296 (3) ◽

pp. R728-R734 ◽

Cited By ~ 15

Author(s):

Ryan Jankord ◽

Richard M. McAllister ◽

Venkataseshu K. Ganjam ◽

M. Harold Laughlin

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Hpa Axis ◽

Acute Exercise ◽

Plasma Concentrations ◽

Exercise Stress ◽

Miniature Swine ◽

Arterial Blood ◽

Oxide Synthase ◽

Response To Exercise

Exercise can activate the hypothalamo-pituitary-adrenocortical (HPA) axis, and regular exercise training can impact how the HPA axis responds to stress. The mechanism by which acute exercise induces HPA activity is unclear. Therefore, the purpose of this study was to test the hypothesis that nitric oxide modulates the neuroendocrine component of the HPA axis during exercise. Female Yucatan miniature swine were treated with N-nitro-l-arginine methyl ester (l-NAME) to test the effect of chronic nitric oxide synthase (NOS) inhibition on the ACTH response to exercise. In addition, we tested the effect of NOS inhibition on blood flow to tissues of the HPA axis and report the effects of handling and treadmill exercise on the plasma concentrations of ACTH and cortisol. Chronic NOS inhibition decreased plasma NOx levels by 44%, increased mean arterial blood pressure by 46%, and increased expression of neuronal NOS in carotid arteries. Vascular conductance was decreased in the frontal cortex, the hypothalamus, and the adrenal gland. Chronic NOS inhibition exaggerated the ACTH response to exercise. In contrast, chronic NOS inhibition decreased the ACTH response to restraint, suggesting that the role of NO in modulating HPA activity is stressor dependent. These results demonstrate that NOS activity modulates the response of the neuroendocrine component of the HPA axis during exercise stress.

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Immunomodulatory Effects of Eisenia bicyclis on Innate Immune Cells in Acute Exercise-Stress Rat Model

Korean Journal of Plant Resources ◽

10.7732/kjpr.2011.24.3.286 ◽

2011 ◽

Vol 24 (3) ◽

pp. 286-291 ◽

Cited By ~ 1

Author(s):

Seung NamKoong ◽

Eui-Su Cheoung ◽

Hae-Mi Joo ◽

Seon-A Jang ◽

Yoon-Jung Yang ◽

...

Keyword(s):

Rat Model ◽

Immune Cells ◽

Acute Exercise ◽

Innate Immune ◽

Exercise Stress ◽

Innate Immune Cells ◽

Immunomodulatory Effects ◽

Eisenia Bicyclis

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PO-068 Influence of different intensity exercise on immune factor in the hot and humid environment

Exercise Biochemistry Review ◽

10.14428/ebr.v1i3.11263 ◽

2018 ◽

Vol 1 (3) ◽

Author(s):

Yan Meng ◽

Yu Yuan ◽

Xiquan Weng

Keyword(s):

Training Program ◽

Acute Exercise ◽

Statistical Significance ◽

Exercise Stress ◽

Time Interval ◽

Group Movement ◽

Hot Environment ◽

Humid Environment ◽

Before And After ◽

Normal Environment

Objective to study the influence of exercise on immune factor IL-2、IL-3、IL-6 in the hot and humid environment by comparing the changes of leukocytes after different intensity exercise with the normal environment，exploring the training program which is beneficial for the immune system in the hot and humid environment, and supply the theoretical basis for the sports training and National Physical Fitness in the hot and humid area. Methods The experimental subjects were 32 healthy male college students of Guangzhou Sports with an average age of 20.9 years. All the subjects tested the maximum oxygen uptake before the experiment, and then were divided into the control group, the 55%VO2max sports group, the 70%VO2max sports group and the 85%VO2max sports group. The experimental subjects took a treadmill running in the normal environment(20-25℃;RH: 55-60%) and finished the same exercise training program in the hot and humid environment(30-32℃；RH：90-95%) after a week, collected the elbow venous blood before and after exercise in the normal environment, The main test indicator contained IL-2、IL-3 and IL-6, Training program: control group sit quietly for 30 min; The 55%VO2max group: Movement×2, 15min one time, Interval 5 min; The 70% VO2max group: Movement×3, 10min one time , Interval 5 min; The 85%VO2max group: Movement ×4, 7.5 min one time , Interval 5 min; All data were calculated using SPSS 25.0, Mean + / - standard deviation (Mean + / - SD), paired T test, single factor variance and multifactor variance analysis. P<0.05 was the significant level, and P<0.01 was the very significant level. Results 1、IL-2 is mainly produced in activated T lymphocytes, which can promote T cell proliferation, improve the secretion and function level of NK cells, play an important role in immune regulation and is an important regulatory factor. Under normal circumstances, IL-2 of the body of each exercise group increased slightly after acute exercise, but there was no statistical significance (p>0.05). In the humid and hot environment, IL-2 decreased in all groups after exercise, and the decrease in the quiet group was large, but there was no statistical significance(p>0.05).2、IL-3 is a multipotent hematopoietic regulatory factor that ACTS on the proliferation and differentiation of hematopoietic cells, mainly produced by activated T lymphocytes. Under normal circumstances, the IL-3 increase of 55% VO2max and 85% VO2max group was not obvious after exercise, while that of 70% VO2max group was not obvious before and after exercise. After acute exercise in hot and humid environment, IL-3 increased in all groups, but there was no statistical significance(p>0.05). Compared with the normal environment, IL-3 increased after exercise in each group.3、IL-6 plays an important role in the regulation of motor mediated function, known as kinematic factor, mainly from stimulated mononuclear macrophages, fibroblasts and vascular endothelial cells. Skeletal muscle can also express IL-6 under exercise stress, which is involved in the repair of muscle cell injury and plays an important regulatory role in skeletal muscle metabolism. Under normal circumstances, after exercise, there was a significant increase in all the exercise groups, among which 55% of the VO2max group and 70% of the VO2max group had a significant difference in IL-6 before and after exercise (p<0.05), and 85% of the VO2max group had a very significant difference (p<0.01). In the humid and hot environment, IL-6 increased after thermal stress in the quiet group, and IL-6 increased significantly after acute exercise in all the exercise groups (p<0.01). Compared with the normal environment, IL-6 increased more significantly and significantly in each group after exercise. Conclusions The combined effect of heat stress and exercise stress on human immune function in the thermal environment is more significant than that of heat stress or exercise stress alone. The greater the intensity of exercise, the decrease of IL-2 and the significant change of IL-6, the more attention should be paid to the temporary immunosuppression caused by excessive intensity of exercise in the humid and hot environment.

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