Nicola D. Hopkins

Background: Humans display an age-related decline in cerebral blood flow and increase in blood pressure (BP), but changes in the underlying control mechanisms across the lifespan are less well understood. We aimed to; (1) examine the impact of age, sex, cardiovascular disease (CVD) risk, and cardio-respiratory fitness on dynamic cerebral autoregulation and cardiac baroreflex sensitivity, and (2) explore the relationships between dynamic cerebral autoregulation (dCA) and cardiac baroreflex sensitivity (cBRS). Methods: 206 participants aged 18–70 years were stratified into age categories. Cerebral blood flow velocity was measured using transcranial Doppler ultrasound. Repeated squat-stand manoeuvres were performed (0.10 Hz), and transfer function analysis was used to assess dCA and cBRS. Multivariable linear regression was used to examine the influence of age, sex, CVD risk, and cardio-respiratory fitness on dCA and cBRS. Linear models determined the relationship between dCA and cBRS. Results: Age, sex, CVD risk, and cardio-respiratory fitness did not impact dCA normalised gain, phase, or coherence with minimal change in all models (P > 0.05). cBRS gain was attenuated with age when adjusted for sex and CVD risk (young–older; β = − 2.86 P < 0.001) along with cBRS phase (young–older; β = − 0.44, P < 0.001). There was no correlation between dCA normalised gain and phase with either parameter of cBRS. Conclusion: Ageing was associated with a decreased cBRS, but dCA appears to remain unchanged. Additionally, our data suggest that sex, CVD risk, and cardio-respiratory fitness have little effect.

Low-cost workplace interventions are required to reduce prolonged sitting in office workers as this may improve employees’ health and well-being. This study aimed to assess the acceptability and feasibility of an e-health intervention to reduce prolonged sitting among sedentary UK-based office workers. Secondary aims were to describe preliminary changes in employee health, mood and work productivity after using an e-health intervention. Healthy, university office workers (n = 14) completed this study. An 8 week randomised crossover design was used, consisting of two trials: Intervention (computer-based prompts) and Control. Eligibility and retention rates were recorded to assess the feasibility of the trial and interviews were conducted following the intervention to explore its acceptability. Sitting, standing and stepping were objectively assessed prior to and during week 8 of each trial. Before and after each trial, measurements of vascular function, cerebrovascular function, mood and work productivity were obtained. This study had eligibility and retention rates of 54.5% and 77.8%, respectively. Participants expressed a lack of autonomy and disruption to their workflow when using the e-health intervention, raising concerns over its acceptability and long-term implementation. Preliminary data indicate that the intervention may improve the patterning of activity accrued during work hours, with increases in the number of standing and stepping bouts completed, in addition to improving vascular function. This e-health intervention is feasible to deliver in a cohort of university office workers. However, adaptations to its implementation, such as personalised settings, are needed to increase acceptability before larger trials can be conducted.

Physical activity reduces cardiovascular mortality and morbidity. The World Health Organisation (WHO) recommends children engage in 60 min daily moderate-to-vigorous physical activity (MVPA). The effect of compliance with this recommendation on childhood cardiovascular risk has not been empirically tested. To evaluate whether achieving recommendations results in reduced composite-cardiovascular risk score (CCVR) in children, and to examine if vigorous PA (VPA) has independent risk-reduction effects. PA was measured using accelerometry in 182 children (9–11 years). Subjects were grouped according to achievement of 60 min daily MVPA (active) or not (inactive). CCVR was calculated (sum of z-scores: DXA body fat %, blood pressure, VO2peak, flow mediated dilation, left ventricular diastolic function; CVR score ≥1SD indicated ‘higher risk’). The cohort was further split into quintiles for VPA and odds ratios (OR) calculated for each quintile. Active children (92 (53 boys)) undertook more MVPA (38 ± 11 min, P < 0.001), had greater VO2peak (4.5 ± 0.8 ml/kg/min P < 0.001), and lower fat % (3.9 ± 1.1 %, P < 0.001) than inactive. No difference were observed between active and inactive for CCVR or OR (P > 0.05). CCVR in the lowest VPA quintile was significantly greater than the highest quintile (3.9 ± 0.6, P < 0.05), and the OR was 4.7 times higher. Achievement of current guidelines has positive effects on body composition and cardiorespiratory fitness, but not CCVR. Vigorous physical activity appears to have beneficial effects on CVD risk, independent of moderate PA, implying a more prescriptive approach may be needed for future VPA guidelines.

Excessive sitting time is a risk factor for cardiovascular disease mortality and morbidity independent of physical activity. This aim of this study was to evaluate the impact of a sit-stand workstation on sitting time, and vascular, metabolic and musculoskeletal outcomes in office workers, and to investigate workstation acceptability and feasibility. A two-arm, parallel-group, individually randomised controlled trial was conducted in one organisation. Participants were asymptomatic full-time office workers aged ≥18 years. Each participant in the intervention arm had a sit-stand workstation installed on their workplace desk for 8 weeks. Participants in the control arm received no intervention. The primary outcome was workplace sitting time, assessed at 0, 4 and 8 weeks by an ecological momentary assessment diary. Secondary behavioural, cardiometabolic and musculoskeletal outcomes were assessed. Acceptability and feasibility were assessed via questionnaire and interview. ANCOVA and magnitude-based inferences examined intervention effects relative to controls at 4 and 8 weeks. Participants and researchers were not blind to group allocation. Forty-seven participants were randomised (intervention n = 26; control n = 21). Relative to the control group at 8 weeks, the intervention group had a beneficial decrease in sitting time (−80.2 min/8-h workday (95 % CI = −129.0, −31.4); p = 0.002), increase in standing time (72.9 min/8-h workday (21.2, 124.6); p = 0.007) and decrease in total cholesterol (−0.40 mmol/L (−0.79, −0.003); p = 0.049). No harmful changes in musculoskeletal discomfort/pain were observed relative to controls, and beneficial changes in flow-mediated dilation and diastolic blood pressure were observed. Most participants self-reported that the workstation was easy to use and their work-related productivity did not decrease when using the device. Factors that negatively influenced workstation use were workstation design, the social environment, work tasks and habits. Short-term use of a feasible sit-stand workstation reduced daily sitting time and led to beneficial improvements in cardiometabolic risk parameters in asymptomatic office workers. These findings imply that if the observed use of the sit-stand workstations continued over a longer duration, sit-stand workstations may have important ramifications for the prevention and reduction of cardiometabolic risk in a large proportion of the working population. ClinicalTrials.gov NCT02496507 .

Flow-mediated dilation (FMD) is a noninvasive technique used to measure conduit artery vascular function. Limited information is available on normative FMD values in healthy children and adolescents. The objective of this study was to assess relationships between age and sex with FMD across childhood and adolescence. Nine hundred and seventy-eight asymptomatic children (12 ± 3 yr, range 6–18 yr, 530 male) underwent ultrasonic brachial artery assessment before and after 5 min of forearm ischemia. Sex differences in FMD and baseline artery diameter were assessed using mixed linear models. Baseline artery diameter was smaller in females than males [2.96 mm (95% CI: 2.92–3.00) vs. 3.24 mm (3.19–3.28), P < 0.001] and increased with age across the cohort (P < 0.001). Diameter increased between ages 6 and 17 yr in males [from 2.81 mm (2.63, 3.00) to 3.91 mm (3.68, 4.14)] but plateaued at age 12 yr in females. Males had a lower FMD [7.62% (7.33–7.91) vs. 8.31% (7.95–8.66), P = 0.024], specifically at ages 17 and 18 yr. There was a significant effect of age on FMD (P = 0.023), with a reduction in FMD apparent postpuberty in males. In conclusion, the brachial artery increases structurally with age in both sexes; however, there are sex differences in the timing and rate of growth, in line with typical sex-specific adolescent growth patterns. Males have a lower FMD than females, and FMD appears to decline with age; however, these findings are driven by reductions in FMD as males near maturity. The use of age- and sex-specific FMD data may therefore not be pertinent in childhood and adolescence.

Context: Kinesiology tape (KT) has become popular among athletes for both injury prevention and rehabilitation due to its reported therapeutic effects, including facilitation of lymphatic flow and enhanced peripheral blood flow. However, evidence to support such claims is insufficient. Objective: To determine whether KT improves skin blood flow (SkBF) responses in young, elite soccer players. Design: Randomized crossover study. Setting: Research laboratory. Patients or Other Participants: Thirteen healthy, elite, adolescent male soccer players (age = 14.7 ± 0.6 years). Intervention(s): Participants completed 2 experimental trials; during trial 1, the volar aspect of the dominant forearm was taped. Forearm SkBF was measured within the taped area and 3 cm lateral to the taped area. During trial 2, no tape was applied to either site. Both trials were performed within 7 days. Main Outcome Measure(s): Baseline and maximal thermally (42°C) stimulated SkBF responses were assessed using laser Doppler flowmetry. Continuously measured SkBF and derived mean arterial pressure obtained at 5-minute intervals were used to calculate cutaneous vascular conductance (CVC), the primary outcome measure. Results: No differences were observed for baseline SkBF or CVC between trials or measurement sites. After local heating, no differences were evident for SkBF or CVC between trials or measurement sites. Conclusions: Our findings suggest that, in healthy, trained adolescent males, KT was not associated with increased forearm SkBF.

Some evidence suggests that sedentary behaviour is independently associated with cardiovascular (CV) risk. Endothelial dysfunction is the earliest detectable manifestation of CVD and a strong independent predictor of CV events. No previous study has examined the relationship between sedentary behaviour and endothelial function. We assessed the basal association between conduit artery endothelial function and sedentary behaviour in children, along with the correlation between changes in sedentary behaviour and endothelial function. We studied 116 children (70♀: 10.7 ± 0.3; 46♂: 10.7 ± 0.3 years) on two occasions; in the summer (June) and late autumn (November). We assessed endothelial function via flow-mediated dilation (FMD) using high-resolution Doppler ultrasound. Sedentary behaviour (SB) was assessed using objective uni-axial accelerometry. At baseline, there were no significant differences between girls and boys for any measured variables with the exception of total physical activity time. FMD was not associated with sedentary behaviour in either group or in the cohort as a whole. Although FMD decreased (10.0 ± 4.3–7.9 ± 3.9%, P < 0.001) and SB increased (499.1 ± 103.5–559 ± 81.6 min/day, P < 0.001) between the seasons, no relationship existed between changes in these variables. Our data suggest that sedentary behaviour and changes in sedentary behaviour are not associated with endothelial function in children.

Flow mediated dilation (FMD) is a surrogate marker of arterial function which can be improved by exercise training. To date, no study has assessed the magnitude of FMD changes in response to exercise training between groups of mono- (MZ) and di-zygotic (DZ) twins. The purpose of this study was therefore to compare FMD in MZ- and DZ twins before and after identical exercise training interventions. At baseline, FMD was assessed using high resolution Duplex ultrasound in 12 twin pairs (6 MZ pairs 13.5 ± 0.8 years, 6 DZ pairs 13.4 ± 0.8 years). Twins completed 8 weeks of exercise training (65–85% HR_max), consisting of three 45-min sessions per week. Change (Δ) scores were entered into twin versus twin intraclass correlation analyses by group. Change in %body fat (r = 0.63, P = 0.05) was significantly correlated in the MZ, but not the DZ group (r = 0.31, P = 0.23). Change in FMD was also highly correlated in MZ (r = 0.74, P = 0.02) but not in the DZ group (r = 0.37, P = 0.18). Heritability of ΔFMD was estimated at 0.74. Exercise induced changes in FMD were similar within sets of monozygotic twins but not dizygotic twins. These data suggest that a significant portion of the arterial function response to exercise training may be genetically determined.