The repeatability of submaximal endurance exercise testing in cystic fibrosis

Submaximal endurance cycle ergometer exercise tests are used to measure the efficacy of an exercise intervention, but the repeatability of these tests in patients with cystic fibrosis (CF) has not been established. The purpose of this study was to examine the repeatability of submaximal endurance testing in stable CF. Fifteen adults with CF underwent two submaximal endurance tests carried out over a 7-day period. A subset of six subjects returned 28 days later for a third submaximal endurance test. Workload was set at 80% of maximum workload and exercise was performed to exhaustion. Oxygen consumption, minute ventilation, tidal volume, carbon dioxide output, respiratory rate, heart rate, and oxygen saturation were measured at rest, at end exercise and at four matched times during the submaximal endurance tests (20, 40, 60, and 80% of exercise duration calculated from the first endurance test). Submaximal endurance test time was highly repeatable with no significant learning effect identified on multiple testing. Submaximal endurance exercise time demonstrated a variability of 5.7% which is consistent with high levels of repeatability. Metabolic, ventilatory and cardiac variables were all also highly reproducible between test days. Submaximal endurance testing is repeatable in stable CF, confirming that submaximal endurance tests are a reliable tool for assessment of therapeutic benefit in patients with CF.     

The effect of endurance exercise on both skeletal muscle and systemic oxidative stress in previously sedentary obese men

Background:

Obesity is associated with low-grade systemic inflammation, in part because of secretion of proinflammatory cytokines, resulting into peripheral insulin resistance (IR). Increased oxidative stress is proposed to link adiposity and chronic inflammation. The effects of endurance exercise in modulating these outcomes in insulin-resistant obese adults remain unclear. We investigated the effect of endurance exercise on markers of oxidative damage (4-hydroxy-2-nonenal (4-HNE), protein carbonyls (PCs)) and antioxidant enzymes (superoxide dismutase (SOD), catalase) in skeletal muscle; urinary markers of oxidative stress (8-hydroxy-2-deoxyguanosine (8-OHdG), 8-isoprostane); and plasma cytokines (C-reactive protein (CRP), interleukin-6 (IL-6), leptin, adiponectin).

Methods:

Age- and fitness-matched sedentary obese and lean men (n=9 per group) underwent 3 months of moderate-intensity endurance cycling training with a vastus lateralis biopsy, 24-h urine sample and venous blood samples taken before and after the intervention.

Results:

Obese subjects had increased levels of oxidative damage: 4-HNE (+37% P⩽0.03) and PC (+63% P⩽0.02); evidence of increased adaptive response to oxidative stress because of elevated levels of copper/zinc SOD (Cu/ZnSOD) protein content (+84% P⩽0.01); increased markers of inflammation: CRP (+737% P⩽0.0001) and IL-6 (+85% P⩽0.03), and these correlated with increased markers of obesity; and increased leptin (+262% P⩽0.0001) with lower adiponectin (−27% P⩽0.01) levels vs lean controls. Training reduced 4-HNE (−10% P⩽0.04), PC (−21% P⩽0.05), 8-isoprostane (−26% P⩽0.02) and leptin levels (−33% P⩽0.01); had a tendency to decrease IL-6 levels (−21% P=0.07) and IR (−17% P=0.10); and increased manganese SOD (MnSOD) levels (+47% P⩽0.01).

Conclusion:

Endurance exercise reduced skeletal muscle-specific and systemic oxidative damage while improving IR and cytokine profile associated with obesity, independent of weight loss. Hence, exercise is a useful therapeutic modality to reduce risk factors associated with the pathogenesis of IR in obesity.     

Resistance exercise and physical performance in adults aged 60 to 83

OBJECTIVES: This investigation examined the effect of 6 months of high- or low-intensity resistance exercise on muscular strength and endurance and stair climbing ability in adults aged 60 to 83. DESIGN: A randomized controlled trial. SETTING: University of Florida Center for Exercise Science. PARTICIPANTS: Sixty-two men and women completed the study protocol. Subjects were matched for strength and randomly assigned to a control (n = 16), low-intensity (LEX, n = 24), or high-intensity (HEX, n = 22) group. INTERVENTION: Six months of progressive, whole-body resistance training. Subjects trained at 50% of their one-repetition maximum (1RM) for 13 repetitions (LEX) or 80% of 1RM for eight repetitions (HEX) three times per week for 24 weeks using resistance machines. One set each of 12 exercises was performed. MEASUREMENTS: One-repetition maximum was measured for eight different exercises. Muscular endurance was measured using leg press and chest press machines. Low back strength was measured using a lumbar extension machine. Stair climbing ability was assessed as the time to ascend one flight of stairs.RESULTS: 1RM significantly increased for all exercises tested for the HEX and LEX groups (P < or =.050). The increases in total strength (sum of all eight 1RMs) were 17.2% and 17.8% for the LEX and HEX groups, respectively. Muscular endurance improved by 79.2% and 105.0% for the leg press, and 75.5% and 68.0% for the chest press for the LEX and HEX groups, respectively. The time to ascend one flight of stairs significantly decreased for both the LEX and HEX groups (P < or =.050). Lumbar extension strength increased by 62.6% and 39.5% for the LEX and HEX groups, respectively. CONCLUSIONS: These data indicate that significant and similar improvements in strength, endurance, and stair climbing time can be obtained in older adults as a consequence of high- or low-intensity resistance exercise training. These findings may have an effect on how resistance exercise is prescribed to older adults.     

Cellular and humoral immune response to a third generation hepatitis B vaccine

Liver transplantation is often the ultimate option of therapy for chronically hepatitis B virus (HBV) infected patients. Adoptive transfer of HBV immunity with the liver after vaccination of living liver donors (LLD) could be a new approach to prevent reinfection in the recipients. The time to achieve HBV immunity in LLD is usually short (1-2 months). Therefore, we established a short time immunization protocol (four injections in 2 weeks intervals) using Hepimmune, a recombinant vaccine that contains the L, M and S proteins of HBV. We examined cellular and humoral immune responses after immunization with Hepimmune and compared its immunogenicity to that of a standard HBV vaccine containing only the S protein (HBVAXPRO). Cellular immunity was measured by interferon (IFN)-gamma ELISpot and proliferation assay. HBV-specific T cells were detectable in the Hepimmune group after the second and in the standard group after the third vaccination. IFN-gamma production of T cells was significantly higher (P < 0.001) after the third vaccination with Hepimmune. Proliferative responses were also significantly (P < 0.01) higher in the Hepimmune group after the second to fourth vaccination. The humoral immune response could already be detected after the first immunization in nine of 15 Hepimmune vaccinated test persons while it was only observed in one of 15 probands of the later group. Titres differed significantly (P < 0.01) following all four vaccinations. Thus, Hepimmune appears to be a good candidate for short time immunization protocols.     

Cellular immune response to the hepatitis C virus

Hepatitis C virus (HCV) infection is most often clinically inapparent and rarely associated with symptoms of acute hepatitis. Most patients, however, fail to resolve the acute infection and proceed to develop chronic hepatitis with the risk of liver cirrhosis and hepatocellular carcinoma later in life. Since the kinetics of the earliest events of virus–host interaction are likely to determine the outcome of infection, research has focused on the characterization of the strength and kinetics of the antiviral immune response in different stages of disease. The identification of the immunological correlates of viral clearance is pivotal for the development of vaccines and efficient therapies.     

围手术康复干预对老年全髋关节置换术后功能水平及运动耐力的影响

目的 探讨围手术康复干预对老年全髋关节置换术(total hip arthroplasty,THA)术后功能水平及运动耐力的影响.方法 选取2020年2月-2021年6月火箭军特色医学中心收治的40例老年全髋关节置换术后患者作为研究对象,用随机数字表法分为观察组和对照组,每组各20例.对照组行THA手术前采取常规健康教...     

Resistance exercise dosage in older adults: single- versus multiset effects on physical performance and body composition

OBJECTIVES: To determine whether variation in resistance exercise volume affects muscle function and physical performance response in older adults. DESIGN: A randomized trial with subjects assigned to a single-set (1-SET) or three-set (3-SET) exercise group. SETTING: An exercise facility at the University of Queensland. PARTICIPANTS: Twenty-eight community-dwelling men and women aged 65 to 78. INTERVENTION: Progressive resistance training consisting of seven exercises targeting the major muscle groups of the upper and lower body performed on exercise machines twice weekly for 20 weeks at eight-repetition maximum (RM) intensity. MEASUREMENTS: Muscle function included isotonic muscle strength (1-RM) of the seven exercises, isokinetic and isometric knee extensor strength, and muscle endurance for the chest press and leg press exercises. Physical performance included timed chair rise, usual and fast 6-m walk, 6-m backwards walk, 400-m walk, floor rise to standing, and stair climbing ability. In addition, body composition was determined using dual energy x-ray absorptiometry. RESULTS: Isotonic muscle strength increased in both exercise groups for all seven exercises (P<.01), with the gain in the 3-SET group greater (P<.05) for the seated row, triceps extension, and knee extension (analysis of covariance). Similarly, muscle endurance gains were greater for the 3-SET than the 1-SET group (P<.01), with no significant difference between groups for isokinetic and isometric knee extensor strength. Both groups improved (P<.05) in the chair rise (1-SET, 10.1%; 3-SET, 13.6%), 6-m backwards walk (1-SET, 14.3%; 3-SET, 14.8%), 400-m walk (1-SET, 3.8%; 3-SET, 7.4%), and stair climbing test (1-SET, 7.7%; 3-SET, 6.4%), with the only difference between groups for the 400-m walk (P<.05). There was no difference between groups for change in body composition. CONCLUSION: Resistance training consisting of only single-set exercises is sufficient to significantly enhance muscle function and physical performance, although muscle strength and endurance gains are greater with higher-volume work. These findings have application in designing time-efficient exercise regimens to enhance neuromuscular function in older adults.     

The acute phase inflammatory response to maximal exercise testing in children and young adults with sickle cell anaemia

Although individuals with sickle cell anaemia (SCA) have elevated baseline inflammation and endothelial activation, the acute phase response to maximal exercise has not been evaluated among children with SCA. We measured the acute phase response to maximal exercise testing for soluble vascular cell adhesion molecule (sVCAM) as well as interleukin 6 (IL6), total white blood cell (WBC) count, C‐reactive protein (CRP) and D‐dimer in a cohort of children with SCA and matched controls at baseline, immediately after, and 30, 60 and 120 min following exercise. Despite higher baseline levels of all biomarkers except CRP, the acute phase response from baseline to immediately after exercise was significantly greater in subjects versus controls for CRP (2·1 vs. 0·2 mg/l, P = 0·02) and D‐dimer (160 vs. 10 μg/l, P < 0·01) only. Similar between‐group trends were observed over time for all biomarkers, including sVCAM, IL6, total WBC, CRP and D‐dimer. Lower fitness, defined by peak oxygen consumption (VO₂), was independently associated with greater acute phase responses to exercise for sVCAM. Our results suggest maximal exercise may not be associated with any greater escalation of endothelial activation or inflammation in SCA and provide preliminary biomarker evidence for the safety of brief, high‐intensity physical exertion in children with SCA.     

Aging-associated insulin resistance predisposes to hypertension and its reversal by exercise: the role of vascular vasorelaxation to insulin

Aging is an independent risk factor for hypertension, and hypertension and insulin resistance commonly coexist in the elderly. This study was designed to examine the effects of aging-related insulin resistance on blood pressure (BP) and its underlying mechanisms, with specific focus on the role of exercise in reversing hypertensive response. Adult (6-month-old) and aging (24-month-old) male Sprague-Dawley rats were subjected to a 10 weeks free-of-loading swim training (60 min/day, 5 days/week). Arterial vasorelaxation, cardiac contraction, eNOS activation, and iNOS and gp91^phox expression were determined. Under aging-related insulin resistance conditions, insulin infusion significantly elevated BP (P < 0.05). Aging caused significant endothelial dysfunction (P < 0.05 − 0.01), which was responsible for decreased arterial vasorelaxation to insulin. Aging attenuated myocardial contractile response to insulin, decreased eNOS expression and its phosphorylation by insulin, and increased iNOS and gp91^phox expression in aging arteries (P < 0.01). Exercise improved insulin sensitivity, potentiated insulin’s positive inotropic effects, facilitated arterial vasorelaxation to insulin, increased arterial eNOS activation in adult and aging rats, and thus attenuated insulin resistance-related hypertensive response to insulin. Moreover, exercise markedly reversed increased iNOS and gp91^phox expression in aging arteries. Inhibition of eNOS with Cavtratin or L-NAME significantly blocked exercise-facilitated arterial vasorelaxation to insulin and exercise-lowered BP response to insulin. In conclusion, these results demonstrate that endothelial dysfunction in response to insulin, but not insulin’s positive inotropic effects, plays an important role in the development of aging-related hypertension. The reversal of hypertensive response to insulin by exercise is most likely associated with improved insulin sensitivity in an eNOS-dependent manner and reduced oxidative and nitrative stresses. Electronic supplementary material:  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Returned for 1. Revision: 18 February 2008 1. Revision received: 11 August 2008 Returned for 2. Revision: 10 September 2008 2. Revision received: 15 September 2008     

Effect of long-term diltiazem treatment on central haemodynamics and exercise endurance in essential hypertension

The effects of long-term treatment with diltiazem on blood pressure,central haemodynamics and exercise endurance were studied in16 men (mean age 52 years) with essential hypertension. Intra-arterialpressureand heart rate (HR) were monitored continuously. Cardiac output(CO) was measured by Cardiogreen at rest (supine and sitting)and during 50 W, 100 Wand 150 W bicycle exercise. Haemodynamicmeasurements were repeated after continous bicycling at 150Wfor 20 min or until exhaustion. After 1 year on diltiazem (meandaily dose 278 mg) intra-arterial pressure was reduced (P <0001)in all situations (at rest sitting from 183/ 108 mmHg to 157/92mmHg (14%)) due to reduction in total peripheral resistance.HR was reduced at rest (7%) and during exercise (10%). Strokevolume tended to increase while CO was unchanged. Exercise timeat constant workload increased by 25%. After apeak level, intra-arterialpressure fell by 3% to 5% (P<0.05) due to a decrease in totalperipheral resistance both before and during diltiazem treatment.Stroke volume and CO remained unchanged during endurance exercisewhile HR showed a small increase. Thus, there was no reductionin the overall cardiac pump function after long-term diltiazemtreatment, and blood flow during exercise was maintained.     

Afterload reduction by nifedipine--the acute haemodynamic response to exercise in hypertensive subjects

In 16 people with essential hypertension, heart rate (HR), bloodpressure (BP) and relative cardiac volumes were measured atrest and during submaximal upright exercise before and after10 mg of sublingual nifedipine using radionuclide ventriculography. In 10 patients who had had no previous therapy (BP 152/103±5/3mmHg) nifedipine produced a fall in BP of 6/12±3/3 mmHg(SEM) and a rise in HR of 15±5 bpm (P<0.001). Thiswas associated with a rise in LVEF of 0.07±0.02 (P<0.005)and in cardiac output of 44±9%, presumably as a resultof ventricular offloading. The cardiac response to exercisegiven the different starting values, was unchanged by nifedipine.Thus the HR was 101±6 bpm at rest after nifedipine andon exercise rose to 124±6 bpm (P<0.001): stroke volumewas +22±8% at rest after nifedipine and rose to +43±12%on exercise. Thus cardiac output which had increased by 44±9%after nifedipine increased by 100±10% from the initialvalue. In 6 patients pre-treated with atenolol (100 mg) and with similarresting BP (158/101±5/4 mmHg) there was a fall in BPof 32/15±3/2 mmHg after nifedipine which was greaterthan in the previously untreated group (P<0.01). In thisgroup HR increased by 8±3 bpm (P<0.05). Followingnifedipine the exercise response was similar given the differentstarting values. The combination of nifedipine and a beta adrenoceptor antagonistcan depress myocardial function and the difference between pressure–volumeratios in the two groups supports this view but there was noimportant depressant effect. We conclude that the combinationof beta blocker and nifedipine therapy is effective and safein hypertensive subjects without significant myocardial dysfunction.     

基于HAPA模式的渐进式抗阻训练对老年慢性阻塞性肺气肿患者健康行为和运动耐力的影响

目的 探讨基于HAPA模式的渐进式抗阻训练对老年慢性阻塞性肺气肿患者健康行为和运动耐力的影响.方法 选取2018年1月至2020年1月我院收治的98例老年慢性阻塞性肺气肿患者,分为观察组63例和对照组35例.对照组采取渐进式抗阻训练进行干预,观察组在对照组的基础上采取健康行动过程模型(HAPA)进行干预,比较两组患者干...     

Influence of Echinococcus multilocularis infection on reproduction and cellular immune response of mice

The influence of secondary Echinococcus multilocularis infection on reproduction and cellular immune response of mice was studied in BALB/c mice infected with 2000 E. multilocularis protoscoleces. Of the total infected mothers, 11·7% did not give birth and 10% of uninfected ones did not deliver. Both, healthy and infected mothers, produced on average 6–7 offspring per litter. The changes in production of seral IFN‐γ, TNF and IL‐10 did not significantly influence the course of gravidity. On the other hand, more intensive metacestode growth was observed after the delivery. This study confirmed the ability of host organism to adapt to severe damage caused by E. multilocularis, not only in normal conditions, but also during pregnancy.     

慢性心力衰竭患者耐量运动训练后体内神经激素的变化

目的　研究耐量运动训练能否对慢性心力衰竭 (CHF)患者血浆中精氨酸血管加压素 (AVP) ,心钠素 (ANP) ,血管紧张素Ⅱ (AngⅡ )和醛固酮 (Aldo)水平有影响 ,延缓病程进展。方法　 12例CHF患者 (冠心病 ,心功能为Ⅱ～Ⅲ级 ,NYHA)隔天在监护下进行耐量运动训练 ,为期 12 0d。在进行耐量运动训练之前和之后 ,采用放射免疫法检测每一患者血浆中在静息状态下和极量平板运动后上述神经激素的水平。结果　经 12 0d的耐量运动训练后 ,静息状态下上述血浆神经激素水平较耐量运动训练前显著降低 (P <0 .0 5 ) ,但极量平板运动后与耐量运动训练前比较则差异无显著性意义 (P >0 .0 5 )。结论　耐量运动训练可降低CHF患者在静息状态下血浆AVP、ANP、AngⅡ和Aldo的水平 ,因此 ,可能有益于延缓CHF患者病程进展。     

Neuromuscular dysfunction in type 2 diabetes: underlying mechanisms and effect of resistance training

Diabetic patients are at higher risk of developing physical disabilities than non‐diabetic subjects. Physical disability appears to be related, at least in part, to muscle dysfunction. Several studies have reported reduced muscle strength and power under dynamic and static conditions in both the upper and lower limbs of patients with type 2 diabetes. Additional effects of diabetes include a reduction in muscle mass, quality, endurance and an alteration in muscle fibre composition, though the available data on these parameters are conflicting. The impact of diabetes on neuromuscular function has been related to the co‐existence of long‐term complications. Peripheral neuropathy has been shown to affect muscle by impairing motor nerve conduction. Also, vascular complications may contribute to the decline in muscle strength. However, muscle dysfunction occurs early in the course of diabetes and affects also the upper limbs, thus suggesting that it may develop independently of micro and macrovascular disease. A growing body of evidence indicates that hyperglycaemia may cause an alteration of the intrinsic properties of the muscle to generate force, via several mechanisms. Recently, resistance exercise has been shown to be an effective strategy to counteract the deterioration of muscular performance. High‐intensity exercise seems to provide greater benefits than moderate‐intensity training, whereas the effect of a power training is yet unknown. This article reviews the available literature on the impairment of muscle function induced by diabetes, the underlying mechanisms, and the effect of resistance training on this defect. Copyright © 2015 John Wiley & Sons, Ltd.     

Prognostic significance of the ST-segment response during exercise test shortly after acute myocardial infarction. Comparison with other exercise variables

A n exercise test was made in 317 patients in the third weekafter acute myocardial infarction. The following types of exerciseassociated ST-segment responses were registered in patientsless than 70-years-old. I: no ST-deviation (33.6%), II: ST-depression(42.9%), III: ST-elevation (13.4%) and IV: inconclusive ST-response(10.1%). The 5-year mortality was significantly lower in groupHI than in groups II and ' IV. Group IV had a significantlyhigher 5-year mortality than all the other groups. Patientswith ST-depression had an increased late mortality comparedto that of the patients without ST-deviation, but the totalmortality did not differ between these two groups. A highlyincreased risk of dying was found in groups I, II and IV inpatients with exercise associated major ventricular arrhythmiasand/or with a small increase of the pressure-rate-product (PRP)during exercise. Patients without arrhythmias and with a highincrease of the PRP had a low mortality rale irrespective oftheir ST-response. In the older patients (70-years-old or more)the ST-response was of no prognostic value at all. The ST-segmentresponse was thus generally of limited value in the prognosticmanagement of the present patients. Their survival was mainlydetermined by the other exercise variables-the magnitude ofan exercise index of left ventricular function and the occurrenceof ventricular arrhythmia