***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background — Aortic stiffness is a marker of cardiovascular disease and an independent predictor of cardiovascular risk . Although an association between inflammatory markers and increased arterial stiffness has been suggested , the causative relationship between inflammation and arterial stiffness has not been investigated . Methods and Results — One hundred healthy individuals were studied according to a r and omized , double-blind , sham procedure-controlled design . Each sub study consisted of 2 treatment arms , 1 with Salmonella typhi vaccination and 1 with sham vaccination . Vaccination produced a significant ( P<0.01 ) increase in pulse wave velocity ( at 8 hours by 0.43 m/s ) , denoting an increase in aortic stiffness . Wave reflections were reduced significantly ( P<0.01 ) by vaccination ( decrease in augmentation index of 5.0 % at 8 hours and 2.5 % at 32 hours ) as a result of peripheral vasodilatation . These effects were associated with significant increases in inflammatory markers such as high-sensitivity C-reactive protein ( P<0.001 ) , high-sensitivity interleukin-6 ( P<0.001 ) , and matrix metalloproteinase-9 ( P<0.01 ) . With aspirin pretreatment ( 1200 mg PO ) , neither pulse wave velocity nor augmentation index changed significantly after vaccination ( increase of 0.11 m/s and 0.4 % , respectively ; P = NS for both ) . Conclusions — This is the first study to show through a cause- and -effect relationship that acute systemic inflammation leads to deterioration of large-artery stiffness and to a decrease in wave reflections . These findings have important implication s , given the importance of aortic stiffness for cardiovascular function and risk and the potential of therapeutic interventions with antiinflammatory properties NO modulates resting blood pressure and wave reflection . The effect of NO on exercise central hemodynamics is unknown but has important implication s relating to cardiovascular risk . The aim of this study was to determine the contribution of NO to pulse pressure ( PP ) amplification and wave reflection during exercise . Twelve healthy men aged 29±1 years ( mean±SEM ) undertook  cycle exercise at 60 % of their maximal heart rate . Noninvasive measures of central blood pressure , estimated aortic pulse wave velocity , and wave reflection ( augmentation index ) were obtained by pulse wave analysis during intravenous infusion of saline ( control ) , NG-monomethyl-l-arginine ( a NO-synthase inhibitor ) , or noradrenaline ( control vasoconstrictor ) . PP amplification was defined as the ratio of peripheral to central PP . Cardiac output and stroke volume were determined by electric bioimpedance . Both NG-monomethyl-l-arginine and noradrenaline caused a significant increase in mean arterial pressure ( P<0.01 ) and augmentation index ( P<0.01 ) , as well as reduced ratio of peripheral to central PP ( P<0.05 ) at baseline . Exercise caused a significant increase in the ratio of peripheral to central PP ( P<0.001 ) , whereas augmentation index and estimated aortic pulse wave velocity declined ( for both P<0.05 ) during all 3 of the infusion protocol s. However , no significant differences were observed in augmentation index , ratio of peripheral to central PP , or estimated aortic pulse wave velocity between infusion procedures ( P>0.50 ) during exercise . Also , heart rate , peripheral vascular resistance , and cardiac output did not differ during exercise between saline , NG-monomethyl-l-arginine , or noradrenaline . Although we can not rule out other vasodilator mechanisms having adjusted for NO blockade , our results indicate that NO does not solely contribute to systemic arterial stiffness or altered blood pressure amplification during light exercise Background We tested the hypothesis that endothelial dysfunction underlies the association between an acute inflammatory episode and the transiently increased risk of a cardiovascular event by examining the effects of an experimental inflammatory stimulus on endothelium-dependent vasodilation . Methods and Results Salmonella typhi vaccine was used to generate a systemic inflammatory response in healthy volunteers . In 12 subjects , dilatation of the brachial artery to flow and to sublingual nitroglycerin ( NTG ) was recorded ( conduit vessel response ) , and in 6 subjects , venous occlusion plethysmography was used to measure forearm blood flow during intrabrachial infusion of the endothelium-dependent dilators acetylcholine ( ACh ) and bradykinin ( BK ) and the endothelium-independent dilators NTG and verapamil ( resistance vessel response ) . Responses were assessed 16 hours before and 8 and 32 hours after vaccination . Vaccination result ed in elevations in white cell count and serum levels of interleukin-6 and interleukin-1 receptor antagonist . Eight hours after vaccination , resistance vessel responses to BK ( P = 0.0099 ) and ACh ( P = 0.0414 ) were markedly attenuated , and brachial artery flow-mediated dilatation was depressed . Resistance vessel responses to verapamil and NTG were unchanged , as was the conduit vessel response to NTG . Thirty-two hours after vaccination , resistance vessel responses to BK and ACh had returned to normal . Conclusions S typhi vaccine generates a mild inflammatory reaction associated with temporary but profound dysfunction of the arterial endothelium in both resistance and conduit vessels to both physical and pharmacological dilator stimuli . This finding might explain the association between infection and inflammation and the enhanced risk of an acute cardiovascular event & NA ; Physical therapists seeking to use evidence to guide their practice may have limited time to read research reports . One way to reduce the time required to identify and read about the research that is relevant to a particular clinical question is to read a systematic review that summarizes multiple studies . This paper explains the process that is used to conduct systematic review s , which includes the establishment of a protocol , comprehensive search ing , appraisal of the quality of the included studies , data extraction and meta analysis , and consideration of the clinical and research implication s of the findings . We also consider how the reader of a systematic review can determine whether the review is likely to provide an unbiased ( believable ) estimate of the treatment effect . A systematic review of r and omized trials of a  cardiopulmonary physical therapy intervention is used as an example . The issue of appraisal of quality is then discussed further , with a demonstration of how one vali date d tool for quality appraisal ‐‐the PEDro scale‐‐can be used to evaluate a r and omized trial in cardiopulmonary physical therapy BACKGROUND The purpose of present study was to determine the acute effects of different aerobic exercise duration on pulse wave velocity ( PWV ) in healthy young men . METHODS One week after measuring peak oxygen uptake to determine the duration of each exercise trial , 11 healthy males ( age : 23.4±0.6 years , height : 172.5±2.3 cm , weight : 64.1±2.4 kg  ) cycled on an ergometer for 15 ( 15 min-EX ) , 30 ( 30 min-EX ) and 45 minutes ( 45 min-EX ) at 65 % peak oxygen uptake in r and om order . After supine rest for at least 15 minutes , aortic ( carotid-femoral ) and leg ( femoral-ankle ) PWV were measured before and at 30 , 60 and 90 minutes after each exercise trial . RESULTS Compared with before exercise trials , aortic PWV decreased at 30 minutes after 15 , 30 and 45 min-EX ( P<0.05 , P<0.01 and P<0.05 , respectively ) and persisted for 60 minutes after 30 and 45 min-EX ( P<0.05 ) , leg PWV decreased at 30 minutes after 15 , 30 and 45 min-EX ( P<0.01 ) and persisted for 60 minutes after 30 and 45 min-EX ( P<0.01 , respectively ) . CONCLUSIONS These results suggest that PWV might be further decreased into recovery with prolonged exercise We tested the hypothesis that acute inflammation may cause arterial stiffening in older adults . We further explored if high cardiorespiratory fitness may partially prevent the unfavorable effect of arterial stiffening produced by acute systemic inflammation in older adults . Using a r and omized double-blind sham placebo-controlled design , forty healthy older adults were assigned to receive either an influenza vaccine or a sham vaccine . C-reactive protein and interleukin 6 ( IL-6 ) were measured as markers of inflammation . Carotid-femoral pulse wave velocity ( PWV ) and augmentation index ( AIX ) as indices of arterial stiffness and wave reflection were assessed at baseline and 24 and 48 h after each vaccination . When compared with sham placebo , the influenza vaccination caused a significant increase in CRP ( p < 0.05 ) and IL-6 ( p < 0.05 ) . Carotid-femoral PWV , but not AIX was significantly increased after influenza vaccination ( p < 0.05 ) , but not sham vaccination . The high cardiorespiratory fitness group had an attenuated increase in PWV as compared to the low cardiorespiratory fitness group after acute inflammation ( p < 0.05 ) . These findings show that acute inflammation may cause significant increases in arterial stiffness in older adults , but these increases were attenuated in the high cardiorespiratory fitness group as compared to the low cardiorespiratory fitness group Background and Objectives Increased central arterial stiffness is an emerging risk factor for cardiovascular disease . Acute aerobic exercise reduces arterial stiffness , while acute resistance exercise may increase arterial stiffness , but this is not a universal finding . We tested whether an acute resistance exercise program was associated with an increase in arterial stiffness in healthy young men . Subjects and Methods Thirteen healthy subjects were studied under parallel experimental conditions on 2 separate days . The order of experiments was r and omized between resistance exercise ( 8 resistance exercises at 60 % of 1 repeated maximal ) and sham control ( seated rest in the exercise room ) . Carotid-femoral pulse wave velocity ( PWV ) and aortic augmentation index as indices of aortic stiffness were measured using applanation tonometry . Measurements were made at baseline before treatments , 20 minutes , and 40 minutes after treatments ( resistance exercise and sham control ) . Results There was no difference in resting heart rate or in arterial stiffness between the two experimental conditions at baseline . At 20 minutes after resistance exercise , heart rate , carotid-femoral PWV and augmentation index@75(% ) were significantly increased in the resistance exercise group compared with the sham control ( p<0.05 ) . Brachial blood pressure , central blood pressure and pulse pressure were not significantly increased after resistance exercise . Conclusion An acute resistance exercise program can increase arterial stiffness in young healthy men . Further studies are needed to clarify the effects of long-term resistance training on arterial stiffness Background Muscle damage induced by unaccustomed or eccentric exercise results in delayed onset vascular stiffening . We tested the hypothesis that a 7-day supplementation of panax ginseng and salvia miltiorrhiza prior to an acute eccentric exercise could attenuate arterial stiffening . Methods By using a double-blind study placebo-controlled r and omized design , subjects were r and omly assigned to either the Chinese herb ( N = 12 ) or the placebo group ( N = 11 ) and performed a downhill running ( eccentric exercise ) trial and a control ( seated rest ) trial . Results Muscle soreness increased 1–2 days after exercise similarly in both groups , whereas the herb group demonstrated a faster recovery on active range of motion . Plasma creatine kinase concentration increased significantly at 24 h in both groups but the magnitude of increase was attenuated in the herb group . Arterial stiffness as measured by carotid-femoral pulse wave velocity increased significantly at 24 h in the placebo group but such increase was absent in the herb group . Flow-mediated dilation did not change in either group . Plasma concentrations of CRP and IL-6 increased in the placebo group but no such increases were observed in the herb group . Changes in arterial stiffness induced by eccentric exercise were associated with the corresponding changes in IL-6 ( r = 0.46 , P < 0.05 ) . Conclusions A short-term Chinese herb supplementation of panax ginseng and salvia miltiorrhiza ameliorated the delayed onset vascular stiffening induced by acute downhill running exercise . Trial registration Clinical Trials.gov : NCT02007304 . Registered Dec. 5 , 2013 An exaggerated blood pressure ( BP ) response to exercise predicts future cardiovascular risk . The mechanisms underlying exercise-induced hypertension remain unclear , although endothelial dysfunction and elevated arterial stiffness may contribute . Given the association between reductions in nitric oxide ( NO ) and vascular dysfunction , we sought to determine whether acute inhibition of NO synthase with NG-monomethyl-L-arginine ( L-NMMA ) would lead to exaggerated BP responses to maximal exercise and attenuate exercise-induced reductions in arterial stiffness . In 10 healthy subjects ( 31±5 years )  , BP and heart rate ( HR ) were measured before , during and after an incremental cycling exercise test 
    Output:
    
Conclusions : Distinct arterial stiffness and wave reflection responses were identified following acute exercise with overall increases in both cf-PWV and AIx75 following resistance exercise potentially arising fromcardiovascular and non-cardiovascular factors that likely differ from those following aerobic exercise .