Overall and repeated measures agreement between brachial-femoral and carotid-femoral measures of pulse wave velocity in young and healthy individuals.

BACKGROUND: Carotid-femoral pulse-wave velocity (cfPWV) is the gold standard measure of arterial stiffness and independently predicts cardiovascular disease. However, obtaining cfPWV requires technical precision and can be difficult in some populations. Brachial-femoral PWV (bfPWV) is a simpler alternative, but there is limited research comparing the two measures. For physiological studies, it is important to know how well the measures agree at rest, and to what extent changes in the measures correspond after perturbation. OBJECTIVE: To assess the overall and repeated measures agreement between cfPWV and bfPWV. METHODS: cfPWV and bfPWV were measured in the supine and seated positions, both before and after a 3-h bout of prolonged sitting. The intraclass correlation coefficient (ICC) for overall agreement was calculated using the random variance components from linear mixed-model regression. Repeated measures agreement (change in cfPWV vs. change in bfPWV) was calculated using repeated measures correlation. RESULTS: Complete data from 18 subjects (22.6 ± 3.1 years old, 33% female) were included in the analysis. There was strong (ICC ≥ 0.70) overall agreement (ICC, 0.75; 95% CI, 0.60-0.85) and very strong (ICC ≥ 0.90) repeated measures agreement (ICC, 0.90; 95% CI, 0.84-0.94) between cfPWV and bfPWV. DISCUSSION: The current findings indicate strong overall agreement and very strong repeated measures agreement between bfPWV and cfPWV. bfPWV is a user-friendly alternative method that agrees with cfPWV-based assessments of central arterial stiffness.

Arterial stiffness responses to prolonged sitting combined with a high-glycemic-index meal: a double-blind, randomized crossover trial.

Regular exposure to uninterrupted prolonged sitting and the consumption of high-glycemic-index (HGI) meals is independently associated with increased cardiovascular disease risk. Sitting for as little as 1 h can impair the health of both peripheral and central arteries. However, it is currently unknown whether combined acute exposure to uninterrupted prolonged sitting and an HGI meal is more detrimental to global (peripheral and central) vascular health. The purpose of this study was to investigate the effect of prolonged sitting (3 h), following the consumption of an HGI or a low-glycemic-index (LGI) meal, on global pulse wave velocity (G-PWV). Eighteen healthy participants [70% female, mean (standard deviation, SD) age = 22.6 (3.1) yr, body mass index (BMI) = 25.5 (6.1) kg/m2] sat for 3 h after consuming an HGI or LGI meal. G-PWV was assessed by incorporating three PWV measures (carotid-femoral, brachial-femoral, and femoral-ankle). The effects of time (PRE vs. POST) and condition (LGI vs. HGI) were analyzed using linear mixed models. Following prolonged sitting, G-PWV increased by 0.29 m/s (i.e., PRE vs. POST). However, the condition (P = 0.987) and time × condition (P = 0.954) effects were nonsignificant. The current findings support previous research showing an increase in arterial stiffness with prolonged sitting. However, in young and healthy adults, the arterial stiffness response was not worsened through HGI meal consumption.NEW & NOTEWORTHY We used novel statistical techniques and study design characteristics to examine how the cardiovascular disruptions due to prolonged sitting are changed after the consumption of low- and high-glycemic-index meals. The current study indicates that changes in arterial stiffness due to prolonged sitting are not worsened in young, healthy adults after the consumption of a high-glycemic-index meal.

Cerebrovascular function response to prolonged sitting combined with a high-glycemic index meal: A double-blind, randomized cross-over trial.

Acute prolonged sitting leads to cerebrovascular disruptions. However, it is unclear how prolonged sitting interacts with other common behaviors, including high- (HGI) and low-glycemic index (LGI) meals. Using a double-blind randomized cross-over design, this study evaluated the effects of prolonged (3 hr) sitting, with a high- (HGI; GI: 100) or low-glycemic index (LGI; GI: 19) meal on total brain blood flow (QBrain ) and executive function. Eighteen young, healthy, active participants (22.6 [3.1] y, 33% F, 24.3 [3.7] kg/m2 ) sat for 3 hr after consuming an HGI or LGI meal. Using Doppler ultrasound to measure internal carotid (ICA) and vertebral (VA) artery blood flow, QBrain was calculated: (ICA blood flow + VA blood flow) × 2. Executive function was assessed using the Stroop Test and Trail Making Test-Part B. Brain fog was measured using a modified Borg Category Scale with Ratio properties (CR10). Following 3 hr of sitting, there was a significant decrease in QBrain with time (p = .001, ES = -0.26), though there were nonsignificant interaction (p = .216) and condition effects (p = .174). Brain fog increased (p = .024, ES = 0.27) and Stroop reaction time worsened with time (p = .001, ES: -0.40), though there were nonsignificant condition effects for brain fog (p = .612) and the Stroop test (p = .445). There was a nonsignificant condition effect (p = .729) for the Trail Making Test-Part B, but completion time improved with time (p = .001, ES = -0.40). In conclusion, 3 hr of prolonged sitting decreases QBrain and executive function independent of glycemic index in young, healthy adults.

Acute Changes in Carotid-Femoral Pulse-Wave Velocity Are Tracked by Heart-Femoral Pulse-Wave Velocity.

Background: Carotid-femoral pulse-wave velocity (cfPWV) is the reference standard measure of central arterial stiffness. However, it requires assessment of the carotid artery, which is technically challenging, and subject-level factors, including carotid artery plaque, may confound measurements. A promising alternative that overcomes these limitations is heart-femoral PWV (hfPWV), but it is not known to what extent changes in cfPWV and hfPWV are associated. Objectives: To determine, (1) the strength of the association between hfPWV and cfPWV; and (2) whether change in hfPWV is associated with change in cfPWV when central arterial stiffness is perturbed. Methods: Twenty young, healthy adults [24.0 (SD: 3.1) years, 45% female] were recruited. hfPWV and cfPWV were determined using Doppler ultrasound at baseline and following a mechanical perturbation in arterial stiffness (120 mmHg thigh occlusion). Agreement between the two measurements was determined using mixed-effects regression models and Bland-Altman analysis. Results: There was, (1) strong (ICC > 0.7) agreement between hfPWV and cfPWV (ICC = 0.82, 95%CI: 0.69, 0.90), and, (2) very strong (ICC > 0.9) agreement between change in hfPWV and cfPWV (ICC = 0.92, 95%CI: 0.86, 0.96). cfPWV was significantly greater than hfPWV at baseline and during thigh occlusion (both P < 0.001). Inspection of the Bland-Altman plot, comparing cfPWV and corrected hfPWV, revealed no measurement magnitude bias. Discussion: The current findings indicate that hfPWV and cfPWV are strongly associated, and that change in cfPWV is very strongly associated with change in hfPWV. hfPWV may be a simple alternative to cfPWV in the identification of cardiovascular risk in clinical and epidemiological settings.

Effects of acute prolonged sitting on cerebral perfusion and executive function in young adults: A randomized cross-over trial.

Exposure to acute prolonged sitting reportedly leads to decreased cerebral blood flow. However, it is unclear whether this exposure translates to decreased cerebral perfusion and executive function or whether simple strategies to break up sitting can maintain cerebral perfusion and executive function. This study sought to answer two questions: in young, healthy adults, (a) does prolonged (3 hr) sitting lead to decreased cerebral perfusion and executive function? and (b) does breaking up prolonged sitting, using intermittent calf raise exercises, prevent changes in cerebral perfusion and executive function? Twenty young, healthy participants (21.7 [2.5] years, 70% female, 25.5 [6.1] kg/m2 ) were randomized to 3 hr sitting with 10 calf raises every 10 min (CALF) and 3 hr sitting without intermittent calf raises (CON). Prefrontal cortex perfusion was assessed using near-infrared spectroscopy to monitor total hemoglobin (tHB) concentration and tissue saturation index (TSI, oxygenated hemoglobin). Executive function was assessed using the Stroop word and color tasks. Following 3 hr sitting, tHb was significantly lower in CALF versus CON (-2.1 µM, 95% CI [-3.1, -1.1]). TSI was not significantly different between conditions (p = .667). Word (1.6 ms, 95% CI [0.7, 2.5]) and color (1.3 ms, 95% CI [-0.2, 2.8]) completion times were longer (worse) for CALF compared to CON. In conclusion, calf raises decreased both cerebral perfusion and executive function. Simple strategies, such as fidgeting or calf raises, which have been reported to preserve vascular function in the legs, appear not to be sufficient to benefit cerebral perfusion or executive function.

Validity and reliability of lower-limb pulse-wave velocity assessments using an oscillometric technique.

NEW FINDINGS: What is the central question of this study? There is growing interest in the effects of sedentarism on central and peripheral cardiovascular health. To permit further investigation, including larger epidemiological studies, there is a need to identify arterial health assessment tools that are valid (accurate) and reliable (precise), yet practical. What is the main finding and its importance? Lower-limb vascular health (femoral-ankle pulse-wave velocity) can be determined in a supine position with accuracy and precision using an oscillometrically based device. This technology might help to improve our understanding of the pathological mechanisms linking cardiovascular disease to sedentarism, including the interaction between peripheral and central vasculature. ABSTRACT: There is a growing interest in the deleterious effects of sedentary behaviour on lower-limb arterial health. To permit further investigation, including larger epidemiological studies, there is a need to identify lower-limb arterial health assessment tools that are valid and reliable, yet simple to administer. In this study, we sought to determine the validity and between-day reliability of femoral-ankle pulse-wave velocity (faPWV) measures obtained using an oscillometrically based device (SphygmocCor XCEL) in supine and seated positions. Doppler ultrasound was used as the criterion. A total of 47 healthy adults were recruited for validity (n = 32) and reliability (n = 15) analyses. Validity was determined by measuring faPWV in seated and supine positions using the XCEL and Doppler ultrasound devices, in a randomized order. Between-day reliability was determined by measuring seated and supine faPWV using the XCEL on three different mornings, separated by a maximum of 7 days. The validity criterion [absolute standard error of estimate (aSEE) < 1.0 m s-1 ] was met in the supine [aSEE = 0.8 m s-1 , 95% confidence interval (CI) 0.4-1.0], but not in the seated (aSEE = 1.2 m s-1 , 95% CI 1.1-1.2) position. Intraclass correlation coefficient (ICC) estimates revealed that the XCEL demonstrated good reliability in the supine position (ICC = 0.83, 95% CI 0.65-0.93), but poor reliability in the seated position (ICC = 0.29, 95% CI 0.23-0.63). The oscillometric XCEL device can be used to determine lower-limb pulse-wave velocity with acceptable validity and reliability in the conventionally recommended supine position, but not in the seated position.

How fitting is F.I.T.T.?: A perspective on a transition from the sole use of frequency, intensity, time, and type in exercise prescription.

The prevalence of physical inactivity continues to rise despite there being sufficient evidence to indicate the appropriate dosage of exercise to mitigate risk for many non-communicable diseases. This rise in physical inactivity is unlikely related to exercise prescription knowledge, but rather in the way exercise is prescribed. Current exercise prescription guidelines are characterized by the FITT Principle: Frequency, Intensity, Time, and Type. In order to target this physical inactivity epidemic, many have focused on the manipulation FITT components. However, perhaps this is not where the focus needs to lie - at least not as FITT is currently defined. Instead, we propose a change may be needed to the way exercise is prescribed - inclusion of measurement of enjoyment. This measurement of enjoyment is crucial to better inform exercise prescription, and may be the missing piece to overcome these high rates of physical inactivity.