Background: Forearm muscle oxygen recovery is a key determinant of fatigue resistance in climbing, yet most assessments are performed in positions that do not reflect actual climbing demands. The influence of handedness on oxygen recovery dynamics also remains unclear. This study examined the effects of upper-limb position and handedness on forearm oxygen recovery in climbers of different ability levels. Methods: Fifty-one male participants, elite climbers (n = 20), intermediate climbers (n = 21), and non-climbing controls (n = 10), completed bilateral arterial occlusion tests in two randomized positions: supine with the arms along the body and seated with the arms elevated to 180° of shoulder flexion. Tissue oxygen saturation (StO₂) over the flexor digitorum profundus was measured using near-infrared spectroscopy. Half-time recovery and reoxygenation rate were calculated after cuff release. Wilcoxon tests assessed the effects of position and handedness, while the Kruskal-Wallis test evaluated group differences. Results: Arm elevation substantially slowed oxygen recovery in both limbs. StO₂ half-time recovery increased from 10.7 ± 2.9 s to 30.3 ± 25.0 s in the dominant and from 10.4 ± 2.4 s to 29.3 ± 22.7 s in the non-dominant limb ( p < 0.001). StO₂ rate decreased from 1.50 ± 0.51 to 0.68 ± 0.7 %/s in the dominant and from 1.62 ± 0.58 to 0.65 ± 0.6 %/s in the non-dominant limb ( p < 0.001). Inter-individual variability was large, with recovery slowing up to 12.6-fold in the elevated position. Handedness had no meaningful influence on oxygen-recovery outcomes at either position ( p = 0.126–0.830). Climbing ability did not affect recovery dynamics, with similar values across elite, intermediate, and control groups ( p = 0.204–0.704). Conclusions: Arm elevation markedly impairs forearm oxygen-recovery dynamics by slowing the restoration of oxygen availability in the forearm flexors, suggesting that reoxygenation is highly sensitive to limb position. The present study introduces an ecologically valid arterial occlusion-reoxygenation test performed with the arm elevated to capture these position-dependent responses in overhead athletes.

Acute psychological stress may contribute to cardiovascular disease risk through transient vascular dysfunction. In a randomized crossover study of healthy young adults, the Trier Social Stress Task increased brachial-femoral pulse wave velocity compared with a neutral time- and speech-matched control condition. Using an experimental design and statistical approach that addressed limitations identified in prior studies, these findings support meta-analytic evidence and suggest that transient arterial stiffening may represent a mechanism linking repeated stress exposure to long-term cardiovascular risk.

Background: Competitive sport climbing has expanded rapidly since its inclusion in the Olympic Games, now comprising three distinct disciplines: lead climbing, bouldering, and speed climbing. Each discipline differs substantially in movement characteristics, duration, and physiological demands. Despite a growing literature base, integrative summaries comparing aerobic and anaerobic demands across disciplines remain limited. Methods: A brief narrative review of the peer-reviewed literature examined the physiological determinants of performance in competitive sport climbing. Studies published from the late nineteen nineties through January twenty-one, two thousand twenty-six were considered, with emphasis on aerobic capacity, anaerobic metabolism, strength, endurance, and local muscle oxygenation. The review followed the Scale for the Assessment of Narrative Review Articles to promote clarity and methodological transparency, prioritizing discipline-specific findings and climbing relevant testing methodologies. Results: Lead climbing is characterized by sustained intermittent loading that requires integrating anaerobic energy production during high-intensity sequences with aerobic mechanisms. Bouldering consists of repeated short-duration maximal efforts that rely primarily on anaerobic glycolytic pathways. Speed climbing is a power-dominant discipline that relies almost exclusively on anaerobic lactic metabolism. Across disciplines, climbing-specific assessments of forearm oxygen kinetics and movement economy show stronger associations with performance than traditional whole-body tests. Conclusion: Sport climbing performance is governed by discipline-specific interactions between aerobic and anaerobic energy systems. Understanding these distinctions is essential for targeted testing and training. Future research should refine sport-specific assessment protocols and clarify how training adaptations influence physiological determinants of performance across climbing disciplines.

Sedentary behaviour is an independent risk factor for cardiovascular disease. In healthy adults, prolonged uninterrupted sitting acutely increases blood pressure (BP) and aortic stiffness; however, these effects can be mitigated with light physical activity interruptions. Whether such mitigation strategies are effective in at-risk populations remains unclear. This study examined the effects of uninterrupted and interrupted sitting on BP and arterial stiffness, measured by carotid-femoral pulse wave velocity (cfPWV), and femoral-ankle PWV in patients with established coronary heart disease (CHD). Using a randomised cross-over design, 14 CHD patients sat for 2 h uninterrupted (control [CON]), and 2 h interrupted with light physical activity (sit-to-stand, calf raises and walking) breaks every 30 min (ACT). Brachial BP and cfPWV were assessed immediately pre- and post-sitting. Time-by-condition effects were tested using linear mixed effects models with baseline adjustments. A significant time × condition interaction effect was detected for systolic BP (P = 0.037) with an increase in CON (mean difference [MD] = 15 mmHg [95% CI: 8, 23], P < 0.001) but not ACT (MD = 4 mmHg [95% CI: -4, 11], P = 0.334). A significant time effect was detected for cfPWV, with an increase across both CON and ACT conditions (MD = 0.76 m/s [95% CI: 0.52, 0.99], P < 0.001). For CHD patients, light activity breaks every 30 min can attenuate the impact of prolonged sitting on BP but not arterial stiffness; higher frequency or intensity of activity breaks may be required for better preservation of cardiovascular function.

Abstract BACKGROUND Sedentary behaviour independently contributes to cardiovascular disease risk. In healthy adults, prolonged uninterrupted sitting acutely elevates blood pressure, whereas light-activity breaks attenuate this response. Whether such strategies confer similar benefits in high-risk populations, such as chronic stroke survivors, remains unanswered. OBJECTIVES To determine whether non-ambulatory, seated heel-raise interruptions every 10 minutes would attenuate central systolic blood pressure (cSBP) during 3 hours of prolonged sitting in individuals with chronic stroke. We hypothesized that the experimental (heel-raise interruption) condition (EXP) would significantly mitigate the cSBPresponse relative to uninterrupted sitting (CON). METHODS Using a randomized crossover design, 15 chronic stroke patients (69.3 ± 10.8 y; 10 male) completed two 3-hour conditions: CON and EXP (10 seated bi-lateral heel raises at 1 rep·s ⁻ ¹ every 10 minutes). Central and peripheral blood pressures were assessed pre- and post-each condition using the SphygmoCor XCEL. Condition × Time interactions were tested using repeated-measures ANOVA. RESULTS The primary hypothesis was confirmed: a significant Condition × Time interaction was detected for cSBP (p < 0.05; η p² = 0.28), with EXP eliciting a smaller increase than CON (5.6 mmHg [−6.4, 17.6] vs. 9.6 mmHg [−2.4, 21.6]). CONCLUSIONS Heel-raise interruptions every 10 minutes attenuate the cSBP response to prolonged sitting in chronic stroke patients and reduce cardiac workload. Frequent, non-ambulatory activity breaks represent a practical secondary prevention strategy for this population, though higher intensity or frequency may be required to fully protect vascular function.

Acute prolonged sitting increases blood pressure (BP) and arterial stiffness (AS). Both of these may be mitigated via light physical activity (LPA). Whether long COVID (LC), which partly manifests as vascular sequelae, predisposes a heightened sensitivity to sitting or diminished benefits from its interruption is unknown. The aims of this study were to identify whether individuals with LC: (i) exhibit a worse BP/AS response to uninterrupted sitting and (ii) a diminished mitigation of BP/AS response to sitting interrupted with LPA, compared to healthy controls. Thirty participants with LC and 15 controls completed 2 h of uninterrupted sitting and sitting interrupted with LPA. Central and peripheral systolic and diastolic BP and carotid-femoral pulse wave velocity (cfPWV) were determined pre and post sitting. Linear mixed-effects models demonstrated no three-way or two-way interactions for any variable. There was a significant main effect of time, with increases in central systolic (MD = 3.37 mmHg, SE = 0.93 mmHg, p < 0.001) and central diastolic (MD = 3.00 mmHg, SE = 0.58 mmHg, p < 0.001) BP. cfPWV was not altered in sitting in either group (MD = 0.13 m/s, SE = 0.09 m/s, p = 0.170). Uninterrupted sitting increases BP similarly, but AS is unchanged. Interrupting sitting with LPA did not mitigate sitting-induced increase in BP regardless of LC diagnosis.

INTRODUCTION:Sedentary behavior, specifically an acute bout of prolonged uninterrupted sitting, is associated with heightened cardiovascular disease (CVD) risk, with increased arterial stiffness (AS) being implicated as a principal pathophysiological mechanism. The current systematic review, with meta-analysis, aimed to consolidate the AS response to (1) prolonged uninterrupted sitting and (2) interrupted sitting, as assessed by central and peripheral pulse wave velocity (PWV). METHODS:In total, 326 articles were identified, of which 11 and seven met the inclusion criteria for objectives (1) and (2), respectively. Mean differences (MD) and 95% CI were calculated for all trials using a three-level random-effects model, with restricted maximum likelihood (REML) estimation. The amount of heterogeneity was estimated using Cochran's Q and Higgins's I2 tests. RESULTS:(1) Prolonged uninterrupted sitting resulted in a significant increase in carotid-femoral (cf) PWV (MD = 0.184 m/s, 95% CI = 0.098 to 0.270, p < 0.0003). (2) Interrupting bouts of prolonged sitting resulted in a significant increase in cf-PWV (MD = 0.127 m/s, 95% CI = 0.044 to 0.209, p < 0.0026) that was lower compared to the uninterrupted sitting. CONCLUSION:An acute bout of uninterrupted sitting appears to increase cf-PWV; although interrupting prolonged sitting with brief physical activity is beneficial, it does not fully mitigate the response.

Objectives This study aimed to determine the feasibility of a group-based pilot programme of low-to-moderate physical activity training, education and social activities, by investigating acceptability, practicality, implementation and efficacy testing. We offer suggestions on programme adaptions for future study. Methods People with a range of chronic respiratory diseases were invited to participate in a pilot 12 week group activity programme. Activities included outdoor walking, tai-chi, education and a range of social activities. Acceptability was determined by participant experiences determined during interviews. Practicality was determined by programme and outcome measure completion, cost and adverse events. Implementation was determined according to whether the programme ran as planned. Efficacy was determined by statistical analyses of outcomes including hand grip strength, timed up and go test, COPD Helplessness Index, COPD Assessment Test, and measures of physical activity via accelerometry. Results Thematic analysis indicated that the “BreatheHappy” programme was acceptable. Seven of nine participants completed eight out of 10 sessions and the majority completed all outcome measures. “BreatheHappy” was therefore considered practical. The programme was not implemented as planned, with only 10 sessions running rather than the 12 intended. There was a significant increase in daily step counts (MD: 1284 95% CI: 240-2329 p: 0.024 effect size: 0.988), stepping time (MD: 16 min 95% CI: 5-27 min p: 0.011 effect size: 1.36) and daily minutes completing light physical activity (MD: 23 95% CI: 6-38 p: 0.006 effect size: 1.6). However, time spent sitting for ≥30 min but ≤60 min significantly increased (MD: 26 95% CI: 0.2-52 min p: 0.049 effect size: 0.931), showing signs of efficacy and changing physical activity behaviour patterns. Discussion A 10-week programme of low-moderate physical activity training, education and social activities shows signs of feasibility for future research. Suggested adaptions for future study include using physical activity measures such as daily step count or light physical activity for a primary outcome, and mental health and social health related outcome measures relatable to participant's beneficial experiences of the programme. Recruitment in future studies will try and reach both those less socially active and possibly those who have completed pulmonary rehabilitation (PR). Venues should be close to efficient transport links whilst different frequencies and durations of programme delivery should be trialled. Adequate funding should be provided for both staff running the programme and blinded research staff for outcome measurement.

Cardiovascular (CV) disease (CVD) is a leading cause of premature death and hospitalization which places a significant strain on health services and economies around the World. Evidence from decades of empirical and observational research demonstrates clear associations between physical activity (PA) and cardiorespiratory fitness (CRF) which can offset the risk of mortality and increase life expectancy and the quality of life in patients. Whilst well documented, the narrative of increased CRF remained pertinent during the coronavirus disease 2019 (COVID-19) pandemic, where individuals with lower levels of CRF had more than double the risk of dying from COVID-19 compared to those with a moderate or high CRF. The need to better understand the mechanisms associated with COVID-19 and those that continue to be affected with persistent symptoms following infection (Long COVID), and CV health is key if we are to be able to effectively target the use of CRF and PA to improve the lives of those suffering its afflictions. Whilst there is a long way to go to optimise PA and CRF for improved health at a population level, particularly in a post-pandemic world, increasing the understanding using a cellular-to-systems approach, we hope to provide further insight into the benefits of engaging in PA.

Independently, both prolonged uninterrupted sitting and the onset of menopause negatively impact markers of cardiovascular risk. Whether their combination augment these responses additively remains unknown. This study assessed whether prolonged uninterrupted sitting causes greater central and peripheral cardiovascular dysfunction in post-menopausal women compared to pre-menopausal women. To address this, 23 healthy women (13 pre-menopausal [43.77 ± 4.30 years] and 10 post-menopausal [57.20 ± 8.55 years]) sat uninterrupted for 2-h. Carotid-femoral pulse wave velocity (cf-PWV), pulse wave analysis (PWA), lower limb venous pooling (HHb), and calf circumference were assessed pre-and post-sitting using general linear mixed models, with age as a covariate. Changes in MAP over time (both between and within groups) was assessed using a two-way repeated-measures-ANOVA. There were no significant interactions for any outcome measures. However, for cf-PWV, there was a significant main effect of group (Δ = 0.854 ± 0.354 m s−1; p = 0.026, ηp2 = 0.707). For PWA, only heart rate (HR) and pressure forwards (Pf) showed significant main effects 13 of time [Δ = 6 ± 1 bts-min−1, p < 0.001, ηp2 = 0.861] and group [Δ = 3.893 ± 1.450 mmHg, p = 0.016, ηp2 = 0.271], respectively. Both HHb (Δ = 2.737 ± 0.952, p = 0.009, ηp2 = 0.742) and calf circumference (Δ = 0.812 ± 0.128 cm, p < 0.001, ηp2 = 0.863) significantly increased over time. Whilst post-menopausal women demonstrated greater overall arterial stiffness (increased cf-PWV at baseline), there was no difference in cardiovascular response (central or peripheral) to 2-h of prolonged sitting between the pre- and post-menopausal women.

Sport climbing requires a combination of physical and cognitive skills, with working memory (WM) playing a crucial role in performance. This study aimed to investigate the association between WM capacity and climbing ability, while considering potential confounding factors including sex, age, education level, and climbing experience. Additionally, the study compared prefrontal cortex (PFC) hemodynamic responses among different climbing ability groups and sex during WM performance. Twenty-eight climbers participated, with WM assessed using the eCorsi task and PFC hemodynamic responses measured with near infrared spectroscopy (NIRS). Initial linear regression analyses revealed no association between WM and climbing ability. However, significant associations were found after adjustment for covariates. Specifically, sex (p = .014), sex in conjunction with age (p = .026), sex combined with climbing experience (p = .022), and sex along with education level (p = .038) were identified as significant predictors of differences in WM between Expert and Elite climbers. Additionally, notable differences in PFC hemodynamic responses were observed between Expert and Elite climbers, as well as between sexes during the WM task, providing support for differences in WM capacity. This study contributes to understanding the complex relationship between WM capacity and climbing performance, emphasizing the need to account for influencing factors in assessments.

We demonstrate that neither cardiorespiratory fitness nor habitual physical activity influence central and peripheral cardiovascular responses to a 2-h bout of uninterrupted sitting in healthy young adults.

BACKGROUND:The aortic-femoral arterial stiffness gradient, calculated as the ratio of lower-limb pulse-wave velocity (PWV) to central (aortic) PWV, is a promising tool for assessing cardiovascular disease (CVD) risk, but whether it predicts incident CVD is unknown. METHODS:We examined the association of the aortic-femoral arterial stiffness gradient measures carotid-femoral stiffness gradient (femoral-ankle PWV divided by carotid-femoral PWV) and the heart-femoral stiffness gradient (femoral-ankle PWV divided by heart-femoral PWV), as well as PWV, with incident CVD (coronary disease, stroke, and heart failure) and all-cause mortality among 3109 participants of the Atherosclerosis Risk in Communities Study cohort (age, 75±5 years; carotid-femoral PWV, 11.5±3.0 m/s), free of CVD. Cox regression was used to estimate hazard ratios (HR) and 95% CIs. RESULTS:Over a median 7.4-year follow-up, there were 322 cases of incident CVD and 410 deaths. In fully adjusted models, only top quartiles of carotid-femoral stiffness gradient (quartile 4: HR, 1.43 [95% CI, 1.03-1.97]; and quartile 3: HR, 1.49 [95% CI, 1.08-2.05]) and heart-femoral stiffness gradient (quartile 4: HR, 1.77 [95% CI, 1.27-2.48]; and quartile 3: HR, 1.41 [95% CI, 1.00-2.00]) were significantly associated with a greater risk of incident CVD. Only high aortic stiffness in combination with low lower-limb stiffness was significantly associated with incident CVD (HR, 1.46 [95% CI, 1.06-2.02]) compared with the referent low aortic stiffness and high lower-limb stiffness. No PWVs were significantly associated with incident CVD. No exposures were associated with all-cause mortality. CONCLUSIONS:The aortic-femoral arterial stiffness gradient may enhance CVD risk assessment in older adults in whom the predictive capacity of traditional risk factors and PWV are attenuated.

Letter to the EditorReply to Liu et al.Craig Paterson, Simon Higgins, Merilin Sikk, Keeron Stone, Simon Fryer, and Lee StonerCraig PatersonDepartment of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, Simon HigginsDepartment of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, Merilin SikkDepartment of Sport, Hartpury University, Hartpury, United Kingdom, Keeron StoneCardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom, Simon FryerSchool of Natural, Social and Sport Sciences, University of Gloucestershire, Gloucester, United Kingdom, and Lee StonerDepartment of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United StatesDepartment of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United StatesPublished Online:21 Jun 2023https://doi.org/10.1152/ajpheart.00319.2023MoreSectionsPDF (242 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat reply: We thank Liu et al. (1) for their thought-provoking letter, in this issue of the American Journal of Physiology-Heart and Circulatory Physiology, to our recent perspectives article (2). Although we and the authors of the letter seem to agree that there is a need for standardized methodological protocols, we differ on our conclusions and ultimate suggestions. In contrast to our suggested standardizations, Liu et al. propose that lower-limb flow-mediated dilation (FMD) assessments should be performed with participants in a seated posture. We appreciate the discourse and believe that these discussions within the literature are a key step toward improving sitting research and moving toward actionable public health policy. The response by Liu et al. predominates on lower-limb artery FMD and makes no mention of pulse wave velocity (PWV) for which we also made recommendations. As such, this response will focus primarily on lower-limb artery FMD.The arguments of Liu et al. (1) broadly center on using the sitting, rather than supine, posture for lower-limb artery FMD assessments as it demonstrates a more ecologically valid measure when assessing the impact of prolonged sitting that can be used to inform public health messaging. We would counter that there are several pertinent issues associated with performing FMD in said posture. Perhaps the biggest obstacle associated with performing lower-limb FMD in the seated posture is the increased influence of the autonomic nervous system (ANS). It is well established that a seated posture increases ANS activity relative to a supine posture (3, 4). It has also been shown that muscle sympathetic nervous activity (MSNA) increases over time during orthostatic stress (5). This is pertinent to FMD assessments as increased leg MSNA has been shown to increase retrograde shear rate and oscillatory shear index, both of which are likely to detrimentally influence FMD responses (6). Although we concede that performing FMD assessments in the seated posture may reduce methodological confounding, the increased role of the ANS while seated undoubtedly increases measurement error. From a mechanistic standpoint, if we are to put value in seated FMD assessments, we argue that measures of ANS activity are required to add context to what we might be observing. In addition to the above points, the seated position also results in increased hydrostatic pressure in the lower limb (7), increased arterial tortuosity (8), decreased blood flow, and therefore reduced shear stress (9). These additional complexities mean that lower-limb artery FMD performed in a seated posture is not solely measuring endothelial function. By contrast, we are not really sure what we are measuring and draw into question the validity of our measure. However, by performing FMD in a supine posture, we attenuate or eliminate some of these confounding physiological variables and may give a truer reflection of endothelial function in the artery being examined.A further consideration is the technically challenging nature of FMD as a measure. FMD is an extremely challenging measure to perform well, in even ideal circumstances, e.g., the brachial artery with participants in a supine posture, and is known to yield high within-subject variability (10, 11). Attempting to perform FMD in a seated posture adds an additional layer of difficulty and variability. One source of variability comes from the typical need to partially extend the knee from a ∼90° angle at rest to ∼20°–30° for assessment. Small differences in the knee angle at the time of assessment could significantly alter the accuracy of shear rate estimations, and thus the ability to statistically correct for shear is compromised. Furthermore, if the angle differs between assessments, i.e., pre- versus post-sitting or condition 1 versus condition 2, an additional source of error will be introduced. Combined, these issues may prevent the use of lower-limb artery FMD in evaluating the impact of sitting in large epidemiological studies.Finally, prognostic value is an important consideration from a public health perspective. Liu et al. (1) rightly highlight the need for valid outcomes that can be used to inform sedentary behavior public health guidelines. We would argue, however, that FMD, whether performed seated or supine, is unlikely to directly inform policy, but rather form part of an informed mechanistic model used in the determination of biological plausibility. In the determination of public health policy, bodies such as the United States Preventative Services Task Force consider intermediate outcomes (12). These intermediate outcomes are those that can be assessed in an acute randomized controlled trial setting (e.g., blood pressure and central arterial stiffness) and have a demonstrated, biologically plausible link to long-term health outcomes (e.g., cardiovascular disease). In contrast to measures such as blood pressure or central arterial stiffness, lower-limb artery FMD does not have any established prognostic value, i.e., it has not been shown to be predictive of cardiovascular disease or mortality and thus is unlikely to be considered an intermediate outcome. As such, lower-limb artery FMD, as an indicator of endothelial function, is more likely to form part of biologically plausible model. To that end, it is important that instances of lower-limb artery FMD are assessing endothelial function without the added complications discussed earlier.In conclusion, although we thank Liu et al. (1) for this discourse, we still maintain that measurements of lower-limb artery FMD should be performed with participants in a supine position following a standardized 10-min post-posture transition rest period to reduce the introduction of additional measurement error from ANS activity, knee angle, hydrostatic pressure, and arterial tortuosity.GRANTSThis work was supported by National Heart, Lung, and Blood Institute Grants R01 HL157187 and R01 HL162805 (both to L.S.).DISCLOSURESNo conflicts of interest, financial or otherwise, are declared by the authors.AUTHOR CONTRIBUTIONSC.P. drafted manuscript; C.P., S.H., M.S., K.S., S.F., and L.S. edited and revised manuscript; C.P., S.H., M.S., K.S., S.F., and L.S. approved final version of manuscript.REFERENCES1. Liu H, O'Brien MW, Rayner S, Kimmerly DS. Are supine assessments an ecologically valid method to characterize sitting-induced declines in lower-limb vascular health? 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Guidelines for the ultrasound assessment of endothelial-dependent flow-mediated vasodilation of the brachial artery: a report of the International Brachial Artery Reactivity Task Force. J Am Coll Cardiol 39: 257–265, 2002 [Erratum in J Am Coll Cardiol 39: 1082, 2002]. doi:10.1016/S0735-1097(01)01746-6.Crossref | PubMed | ISI | Google Scholar12. Wolff TA, Krist AH, LeFevre M, Jonas DE, Harris RP, Siu A, Owens DK, Gillman MW, Ebell MH, Herzstein J, Chou R, Whitlock E, Bibbins-Domingo K. Update on the Methods of the U.S. Preventive Services Task Force: Linking Intermediate Outcomes and Health Outcomes in Prevention. Am J Prev Med 54: S4–S10, 2018. doi:10.1016/j.amepre.2017.08.032.Crossref | PubMed | ISI | Google ScholarAUTHOR NOTESCorrespondence: C. Paterson ([email protected]edu). Download PDF Previous Back to Top FiguresReferencesRelatedInformation Related ArticlesAre supine assessments an ecologically valid method to characterize sitting-induced declines in lower-limb vascular health? 21 Jun 2023American Journal of Physiology-Heart and Circulatory Physiology More from this issue > Volume 325Issue 1July 2023Pages H145-H146 Crossmark Copyright & PermissionsCopyright © 2023 the American Physiological Society.https://doi.org/10.1152/ajpheart.00319.2023PubMed37342016History Received 31 May 2023 Accepted 31 May 2023 Published online 21 June 2023 Published in print 1 July 2023 Keywordscardiovascularmeasurementpostureprolonged sittingsedentary behavior Metrics

Objective Pulse-wave velocity (PWV), a common measure of arterial stiffness, can be measured continuously and across multiple body sites using photoplethysmography (PPG). The objective was to determine whether a simple photoplethysmography PPG PWV method agrees with a referent device. Approach Photoplethysmography heart-finger PWV (hfPWV) and heart-toe PWV (htPWV) were compared to oscillometric carotid-wrist PWV (cwPWV) and carotid-ankle PWV (caPWV) referent measurements, respectively. In 30 adults (24.6 ± 4.8 years, body mass index 25.2 ± 5.9 kg/m2, 18 female), three measurements were made: two supine baseline measurements (Base 1, Base 2) and one measurement (Tilt) 5 min after a modified head-up tilt test (mHUTT). Overall agreement and repeated measures agreement (change in PPG PWV from Base to Tilt vs. change in referent PWV from Base to Tilt) were calculated using linear mixed models. Agreement estimates were expressed as intra-class correlation coefficients (ICC). Main results For hfPWV there was strong overall agreement (ICC: 0.77, 95%CI: 0.67–0.85), but negligible and non-significant repeated measures agreement (ICC: 0.10, 95%CI: −0.18 to 0.36). For htPWV, there was moderate overall agreement (ICC:0.50, 95%CI: 0.31–0.65) and strong repeated measures agreement (ICC: 0.81, 95%CI: 0.69–0.89). Significance Photoplethysmography can continuously measure PWV at multiple arterial segments with moderate-strong overall agreement. While further work with upper-limb PPG PWV is needed, PPG can adequately capture acute changes in lower-limb PWV.

Low intensity active recovery such as walking appears to be optimal for the clearance of blood lactate (BLa) concentration following high intensity exercise. However, within a sporting context, competition rules or procedural impracticalities often mean walking is not possible. Leg fidgeting during sitting has been shown to increase leg blood flow, which may impact BLa clearance. The purpose of this study was to determine whether leg fidgeting stimulates BLa clearance following high intensity exercise. Using a randomized crossover design, fifteen (7 female) university athletes performed a 30 s Wingate test followed by 15 min of either passive seated rest, or seated leg fidgeting. BLa, heart rate (HR) and rate of perceived exertion (RPE) were assessed pre, immediately post and post 3, 6, 9, 12, and 15 min. There was a significant ( p < 0.05) condition × time interaction for BLa. Post hoc analysis found that leg fidgeting caused a significantly greater reduction in BLa compared to sitting at post 6 (fidget 9.9 ± 2.6 vs. sitting 9.9 ± 2.2 mmol·L−1), 9 (9.3 ± 2.3 vs. 9.9 ± 2.1 mmol·L−1), 12 (8.8 ± 2.3 vs. 9.5 ± 2.2 mmol·L−1) and 15 (7.6 ± 2.1 vs. 8.6 ± 2.2 mmol·L−1) min respectively. Overall, leg fidgeting improved BLa clearance by 10% more than passive recovery. No significant interactions were found for HR or RPE. Following high intensity exercise, leg fidgeting may be considered a useful alternative to whole body active recovery when walking is not permitted.

Exposure to acute prolonged sitting and consumption of a high fat (HF) meal have been shown to independently and additively impair central and peripheral cardiovascular function. This study sought to determine whether localized activity, namely leg fidgeting, offers a protective effect to these deleterious effects. Using a randomized crossover design with three trials, 18 healthy males sat uninterrupted for 180 min following the consumption of a low fat (LF, trial 1) or HF meal (trial 2). The third trial consisted of a HF meal but sitting was interrupted with 1 min of leg fidgeting (isolated bilateral plantar flexion) consisting of −250 taps per min every 5 min for the 180 min duration. Carotid-femoral pulse wave velocity (cfPWV), aortic-femoral stiffness gradient (af-SG), superficial femoral blood flow, shear-rate and PWV β , triglyceride concentrations and lower-limb venous pooling (HHb) were assessed pre and post sitting in all trials. General linear mixed model found that following the uninterrupted HF trial, there was a significant worsening of cfPWV (mean difference (MD) = 0.57 mˑs −1 ; d = 1.04) and the af-SG (MD = 0.14, d = 0.50), and femoral artery blood flow (MD = 18 mlˑmin −1 ; d = 0.48) and shear rate (MD = 15 S 1 ; d = 0.67) decreased. However, leg fidgeting was enough to prevent the combined deleterious effects of prolonged sitting following a HF meal. As there were no significant changes in the LF trial, the HF meal maybe the predominant driver when uninterrupted sitting is combined with a HF meal.

EDITORIAL article Front. Physiol., 13 April 2023Sec. Exercise Physiology Volume 14 - 2023 | https://doi.org/10.3389/fphys.2023.1197926

Overground robotic-assisted gait training (O-RAGT) has been shown to improve clinical functional outcomes in people living with stroke. The purpose of this study was to identify whether a home-based O-RAGT program, in combination with usual care physiotherapy, would demonstrate improvements in vascular health in individuals with chronic stroke, and, whether any changes in vascular outcomes would be sustained 3 months after completing the program. Thirty-four participants with chronic stroke (between 3 months and 5 years post-stroke) were randomized to either a 10-week O-RAGT program in combination with usual care physiotherapy, or to a usual care physiotherapy only control group. Participants' (n = 31) pulse wave analysis (PWA), and regional [carotid-femoral pulse wave analysis (cfPWV)] and local (carotid) measures of arterial stiffness were assessed at baseline, post-intervention, and 3-month post-intervention. Analysis of covariance demonstrated a significant reduction (improvement) in cfPWV between BL and PI for O-RAGT (8.81 ± 2.51 vs. 7.92 ± 2.17 m/s, respectively), whilst the control group remained unchanged (9.87 ± 2.46 vs. 9.84 ± 1.76 m/s, respectively; p < 0.05; ηp2 = 0.14). The improvement in cfPWV was maintained 3 months after completing the O-RAGT program. There were no significant Condition by Time interactions for all PWA and carotid arterial stiffness measures (p > 0.05). A significant increase in physical activity, as determined by the time spent stepping, was observed for O-RAGT between baseline and post-intervention assessments (3.2 ± 3.0–5.2 ± 3.3%, respectively) but not for CON (p < 0.05). The improvement in cfPWV, in combination with an increase in physical activity whilst wearing the O-RAGT and concomitant reduction in sedentary behavior, are important positive findings when considering the application of this technology for “at home” rehabilitation therapy for stroke survivors. Further research is needed to determine whether implementing “at home” O-RAGT programs should be a part of the stroke treatment pathway.Clinical trial registrationhttps://clinicaltrials.gov, identifier NCT03104127.

Sedentary behavior has been identified as an independent predictor of future cardiovascular disease risk and all-cause mortality. To explain this association, a growing body of literature has sought to investigate the physiological underpinnings of this association with the goal of developing a biologically plausible model. In time, this biologically plausible model can be tested, and effective, translatable public health guidelines can be developed. However, to ensure that evidence across studies can be effectively synthesized, it is necessary to ensure their congruency and comparability. Although there are several key factors that should be considered and controlled across prolonged sitting studies, one pertinent issue is that of participant posture. There is currently a discourse within the literature regarding the posture that cardiovascular assessments are performed in and rest periods between posture transitions and subsequent measures. This perspectives piece makes the case for standardizing approaches across the research area and offers practical recommendations for future work.