Imperial College London

DrDavidLow

Faculty of MedicineDepartment of Surgery & Cancer

Honorary Senior Lecturer
 
 
 
//

Contact

 

+44 (0)1519 046 244david.low

 
 
//

Location

 

//

Summary

 

Publications

Publication Type
Year
to

161 results found

Somani YB, Boidin M, Peggen MAG, Wanders I, Proctor DN, Low DA, Jones H, Lip GYH, Thijssen DHJet al., 2024, Single and 7-day handgrip and squat exercise prevents endothelial ischemia-reperfusion injury in individuals with cardiovascular disease risk factors., Am J Physiol Regul Integr Comp Physiol, Vol: 326, Pages: R79-R87

Whole body exercise provides protection against endothelial ischemia-reperfusion (IR) injury. In this crossover study, we examined the effects of 1) single bout of local exercise (handgrip, squats) on endothelial responses to IR, and 2) if 7 days of daily local exercise bolsters these effects in individuals with cardiovascular disease (CVD) risk factors. Fifteen participants (9 women, 58 ± 5 yr, ≥2 CVD risk factors) attended the laboratory for six visits. Subsequent to familiarization (visit 1), during visit 2 (control) brachial artery flow-mediated dilation (FMD) was measured before and after IR (15-min upper-arm ischemia, 15-min reperfusion). One week later, participants were randomized to 4 × 5-min unilateral handgrip (50% maximal voluntary contraction, 25 rpm) or squat exercises (15 rpm), followed by IR plus FMD measurements. Subsequently, home-based exercise was performed (6 days), followed by another visit to the laboratory for the IR protocol plus FMD measurements (18-24 h after the last exercise bout). After a 2-wk washout period, procedures were repeated with the alternative exercise mode. For a single exercise bout, we found a significant IR injury × exercise mode interaction (P < 0.01) but no main effect of injury (P = 0.08) or condition (P = 0.61). A lower post-IR FMD was evident after control (pre-IR: 4.3 ± 2.1% to post-IR: 2.9 ± 1.9%, P < 0.01) but not after handgrip (pre-IR: 3.8 ± 1.6% to post-IR: 3.4 ± 1.5%, P = 0.31) or squats (pre-IR: 3.9 ± 1.8% to post-IR: 4.0 ± 1.9%, P = 0.74). After 7 days of daily exercise, we found no change in FMD post-IR following handgrip (pre-IR: 4.3 ± 1.9% to post-IR: 4.7 ± 3.2%) or squats (pre-IR: 3.7 ± 2.1% to post-IR: 4.7 ± 3.0%, P > 0.05). Single bouts o

Journal article

Fecchio RY, de Sousa JCS, Oliveira-Silva L, da Silva Junior ND, Pio-Abreu A, da Silva GV, Drager LF, Low DA, Forjaz CLMet al., 2023, Effects of dynamic, isometric and combined resistance training on blood pressure and its mechanisms in hypertensive men., Hypertens Res, Vol: 46, Pages: 1031-1043

Although dynamic resistance training (DRT) and isometric handgrip training (IHT) may decrease blood pressure (BP) in hypertensives, the effects of these types of training have not been directly compared, and a possible additive effect of combining IHT to DRT (combined resistance training-CRT), has not been investigated. Thus, this study compared the effects of DRT, IHT and CRT on BP, systemic hemodynamics, vascular function, and cardiovascular autonomic modulation. Sixty-two middle-aged men with treated hypertension were randomly allocated among four groups: DRT (8 exercises, 50% of 1RM, 3 sets until moderate fatigue), IHT (30% of MVC, 4 sets of 2 min), CRT (DRT + IHT) and control (CON - stretching). In all groups, the interventions were administered 3 times/week for 10 weeks. Pre- and post-interventions, BP, systemic hemodynamics, vascular function and cardiovascular autonomic modulation were assessed. ANOVAs and ANCOVAs adjusted for pre-intervention values were employed for analysis. Systolic BP decreased similarly with DRT and CRT (125 ± 11 vs. 119 ± 12 and 128 ± 12 vs. 119 ± 12 mmHg, respectively; P < 0.05), while peak blood flow during reactive hyperaemia (a marker of microvascular function) increased similarly in these groups (774 ± 377 vs. 1067 ± 461 and 654 ± 321 vs. 954 ± 464 mL/min, respectively, P < 0.05). DRT and CRT did not change systemic hemodynamics, flow-mediated dilation, and cardiovascular autonomic modulation. In addition, none of the variables were changed by IHT. In conclusion, DRT, but not IHT, improved BP and microvascular function in treated hypertensive men. CRT did not have any additional effect in comparison with DRT alone.

Journal article

Thomas SD, Carter HH, Jones H, Roberts KA, Thijssen D, Low DAet al., 2023, Acute impact of aerobic exercise on local cutaneous thermal hyperaemia., Microvasc Res, Vol: 146

Little is known about the acute changes in cutaneous microvascular function that occur in response to exercise, the accumulation of which may provide the basis for beneficial chronic cutaneous vascular adaptations. Therefore, we examined the effects of acute exercise on cutaneous thermal hyperaemia. Twelve healthy, recreationally active participants (11 male, 1 female) performed 30-minute cycling at 50 % (low-intensity exercise, LOW) or 75 % (high-intensity exercise, HIGH) maximum heart rate. Laser Doppler flowmetry (LDF) and rapid local skin heating were used to quantify cutaneous thermal hyperaemia before (PRE), immediately following (IMM) and 1-h (1HR) after exercise. Baseline, axon reflex peak, axon reflex nadir, plateau, maximum skin blood flow responses to rapid local heating (42 °C for 30-min followed by 44 °C for 15-min) at each stage were assessed and indexed as cutaneous vascular conductance [CVC = flux / mean arterial blood pressure (MAP), PU·mm Hg-1], and expressed as a percentage of maximum (%CVCmax). Exercise increased heart rate (HR), MAP and skin blood flow (all P < 0.001), and to a greater extent during HIGH (all P < 0.001). The axon reflex peak and nadir were increased immediately and 1-h after exercise (all comparisons P < 0.01 vs. PRE), which did not differ between intensities (peak: P = 0.34, axon reflex nadir: P = 0.91). The endothelium-dependent plateau response was slightly elevated after exercise (P = 0.06), with no effect of intensity (P = 0.58) nor any interaction effect (P = 0.55). CONCLUSION: Exercise increases cutaneous microvascular axonal responses to local heating for up to 1-h, suggesting an augmented sensory afferent function post-exercise. Acute exercise may only modestly affect endothelial function in cutaneous microcirculation.

Journal article

Bannell DJ, Montrezol FT, Maxwell JD, Somani YB, Low DA, Thijssen DHJ, Jones Het al., 2023, Impact of handgrip exercise and ischemic preconditioning on local and remote protection against endothelial reperfusion injury in young men, AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY, Vol: 324, Pages: R329-R335, ISSN: 0363-6119

Journal article

Barton T, Low DA, Thijssen DHJ, Romviel S, Sloots M, Smit CAJ, Janssen TWJet al., 2022, Twelve-Week Daily Gluteal and Hamstring Electrical Stimulation Improves Vascular Structure and Function, Limb Volume, and Sitting Pressure in Spinal Cord Injury: A Pilot Feasibility Study., Am J Phys Med Rehabil, Vol: 101, Pages: 913-919

OBJECTIVE: We examined the long-term effects of low-intensity electrical stimulation on (micro)vasculature and sitting pressure of a home-based, wearable electrical stimulation device in a pilot feasibility study. DESIGN: In a cohort observation before-after trial, nine middle-aged male (n = 8) and female (n = 1) individuals (48 ± 15 yrs) with American Spinal Injury Association A-C classified chronic (1-24 yrs) spinal cord injury underwent 12 wks of self-administered daily, low-intensity gluteal and hamstring electrical stimulation (50 Hz, 6 hrs [30-min electrical stimulation, 15-min rest]). Common femoral artery diameter and blood blow were determined with ultrasound, skin vascular function during local heating was assessed using Laser-Doppler flowmetry, thigh volume was estimated using leg circumferences and skinfolds, and interface sitting pressure was measured using pressure mapping. RESULTS: Resting common femoral artery diameter increased (0.73 ± 0.20 to 0.79 ± 0.22 cm, P < 0.001) and baseline common femoral artery blood flow increased (0.28 ± 0.12 to 0.40 ± 0.15 l/min, P < 0.002). Gluteal cutaneous vascular conductance showed a time*temperature interaction (P = 0.01) with higher conductance at 42°C after 12 wks. Ischial peak pressure decreased (P = 0.003) by 32 ± 23 mm Hg and pressure gradient decreased (23 ± 7 to 16 ± 6 mm Hg, P = 0.007). Thigh volume increased (+19%, P = 0.01). CONCLUSIONS: Twelve-week daily home-based gluteal and hamstring electrical stimulation is feasible and effective to improve (micro)vasculature and sitting pressure, and electrical stimulation may have clinical implications for ameliorating pressure ulcers and (micro)vascular complications in spinal cord injury.

Journal article

France-Ratcliffe M, Hopkins ND, Low DA, Cocks MS, Jones H, Sheen KS, Sprung VSet al., 2022, Perceptions of Antenatal Exercise in Pregnant Females and the Impact of COVID-19, INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH, Vol: 19

Journal article

Mawhinney C, Heinonen I, Low DA, Han C, Jones H, Kalliokoski KK, Kirjavainen A, Kemppainen J, DI Salvo V, Lolli L, Cable NT, Gregson Wet al., 2022, Cool-Water Immersion Reduces Postexercise Quadriceps Femoris Muscle Perfusion More Than Cold-Water Immersion., Med Sci Sports Exerc, Vol: 54, Pages: 1085-1094

PURPOSE: The muscle perfusion response to postexercise cold-water immersion (CWI) is not well understood. We examined the effects of graded postexercise CWI upon global and regional quadriceps femoris muscle perfusion using positron emission tomography and [15O]H2O. METHODS: Using a matched-group design, 30 healthy men performed cycle ergometer exercise at 70% V̇O2peak to a core body temperature of 38°C, followed by either 10 min of CWI at 8°C, 22°C, or seated rest (control). Quadriceps muscle perfusion; thigh and calf cutaneous vascular conductance; intestinal, muscle, and local skin temperatures; thermal comfort; mean arterial pressure; and heart rate were assessed at preexercise, postexercise, and after CWI. RESULTS: Global quadriceps perfusion was reduced beyond the predefined minimal clinically relevant threshold (0.75 mL per 100 g·min-1) in 22°C water versus control (difference (95% confidence interval (CI)), -2.5 (-3.9 to -1.1) mL per 100 g·min-1). Clinically relevant decreases in muscle perfusion were observed in the rectus femoris (-2.0 (-3.0 to -1.0) mL per 100 g·min-1) and vastus lateralis (-3.5 (-4.9 to -2.0) mL per 100 g·min-1) in 8°C water, and in the vastus lateralis (-3.3 (-4.8 to -1.9) mL per 100 g·min-1) in 22°C water versus control. The mean effects for vastus intermedius and vastus medialis perfusion were not clinically relevant. Clinically relevant decreases in thigh and calf cutaneous vascular conductance were observed in both cooling conditions. CONCLUSIONS: The present findings revealed that less noxious CWI (22°C) promoted clinically relevant postexercise decreases in global quadriceps muscle perfusion, whereas noxious cooling (8°C) elicited no effect.

Journal article

Maxwell JD, Bannell DJ, Brislane A, Carter SE, Miller GD, Roberts KA, Hopkins ND, Low DA, Carter HH, Thompson A, Claassen JAHR, Thijssen DHJ, Jones Het al., 2022, The impact of age, sex, cardio-respiratory fitness, and cardiovascular disease risk on dynamic cerebral autoregulation and baroreflex sensitivity., Eur J Appl Physiol, Vol: 122, Pages: 1531-1541

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.

Journal article

Zignoli A, Fornasiero A, Rota P, Muollo V, Peyré-Tartaruga LA, Low DA, Fontana FY, Besson D, Pühringer M, Ring-Dimitriou S, Mourot Let al., 2022, Oxynet: A collective intelligence that detects ventilatory thresholds in cardiopulmonary exercise tests., Eur J Sport Sci, Vol: 22, Pages: 425-435

The problem of the automatic determination of the first and second ventilatory thresholds (VT1 and VT2) from cardiopulmonary exercise test (CPET) still leads to controversy. The reliability of the gold standard methodology (i.e. expert visual inspection) feeds into the debate and several authors call for more objective automatic methods to be used in the clinical practice. In this study, we present a framework based on a collaborative approach, where a web-application was used to crowd-source a large number (1245) of CPET data of individuals with different aerobic fitness. The resulting database was used to train and test an artificial intelligence (i.e. a convolutional neural network) algorithm. This automatic classifier is currently implemented in another web-application and was used to detect the ventilatory thresholds in the available CPET. A total of 206 CPET were used to evaluate the accuracy of the estimations against the expert opinions. The neural network was able to detect the ventilatory thresholds with an average mean absolute error of 178 (198) mlO2/min (11.1%, r = 0.97) and 144 (149) mlO2/min (6.1%, r = 0.99), for VT1 and VT2 respectively. The performance of the neural network in detecting VT1 deteriorated in case of individuals with poor aerobic fitness. Our results suggest the potential for a collective intelligence system to outperform isolated experts in ventilatory thresholds detection. However, the inclusion of a larger number of VT1 examples certified by a community of experts will be likely needed before the abilities of this collective intelligence can be translated into the clinical use of CPET.

Journal article

Miller GD, Maxwell JD, Thompson A, Cable NT, Low DA, George KP, Jones Het al., 2022, The effects of exercise training in the cold on cerebral blood flow and cerebrovascular function in young healthy individuals., Auton Neurosci, Vol: 238

Exercise elicits acute increases in cerebral blood flow velocity (CBFv) and provokes long-term beneficial effects on CBFv, thereby reducing cerebrovascular risk. Acute exposure to a cold stimulus also increases CBFv. We compared the impact of exercise training in cold and thermoneutral environments on CFBv, cerebrovascular function and peripheral endothelial function. Twenty-one (16 males, 22 ± 5 years) individuals were randomly allocated to either a cold (5 °C) or thermoneutral (15 °C) exercise intervention. Exercise consisted of 50-min cycling at 70% heart rate max, three times per week for eight weeks. Transcranial Doppler was used to determine pre and post intervention CBFv, dynamic cerebral autoregulation (dCA) and cerebrovascular reactivity (CVRCO2). Conduit endothelial function, microvascular function and cardiorespiratory fitness were also assessed. Cardiorespiratory fitness improved (2.91 ml.min.kg-1, 95%CI 0.49, 5.3; P = 0.02), regardless of exercise setting. Neither intervention had an impact on CBFv, CVRCO2, FMD or microvascular function (P > 0.05). There was a significant interaction between time and condition for dCA normalised gain with evidence of a decrease by 0.192%cm.s-1.%mmHg-1 (95%CI -0.318, -0.065) following training in the cold and increase (0.129%cm.s-1.%mmHg-1, 95%CI 0.011, 0.248) following training in the thermoneutral environment (P = 0.001). This was also evident for dCA phase with evidence of an increase by 0.072 rad (95%CI -0.007, 0.152) following training in the cold and decrease by 0.065 (95%CI -0.144, 0.014) radians following training in the thermoneutral environment (P = 0.02). Both training interventions improved fitness but CBFv, CVRCO2 and peripheral endothelial function were unaltered. Exercise training in the cold improved dCA whereas thermoneutral negated dCA.

Journal article

Mathias CJ, Low DA, Claydon VE, 2022, Autonomic disturbances following spinal cord injury, Primer on the Autonomic Nervous System, Fourth Edition, Pages: 599-606, ISBN: 9780323854931

Normal functioning of the autonomic nervous system is critically dependent on integrity of the spinal cord, as descending autonomic pathways that regulate the entire sympathetic outflow and the sacral parasympathetic outflow travel and also synapse within the spinal cord before supplying various target organs. In individuals with spinal cord injury (SCI), therefore, autonomic impairment is common, and may affect the cardiovascular, thermoregulatory, sudomotor, gastrointestinal, urinary, respiratory, and reproductive systems. The severity of autonomic impairment depends upon the site and the extent of the lesion. In individuals with cervical and high thoracic SCI, the entire or a large part of the sympathetic outflow, together with the sacral parasympathetic outflow, may be separated from cerebral control, and so autonomic dysfunction is usually more pronounced in those with higher lesions. Treatment for autonomic dysfunction after SCI usually involves a combination of nonpharmacological and pharmacological interventions.

Book chapter

Barton TJ, Low DA, Bakker EA, Janssen T, de Groot S, van der Woude L, Thijssen DHJet al., 2021, Response to Letter to the Editor on "Traditional Cardiovascular Risk Factors Strongly Underestimate the 5-Year Occurrence of Cardiovascular Morbidity and Mortality in Spinal Cord Injured Individuals"., Arch Phys Med Rehabil, Vol: 102, Pages: 2269-2270

Journal article

Peçanha T, Bannell DJ, Sieczkowska SM, Goodson N, Roschel H, Sprung VS, Low DAet al., 2021, Effects of physical activity on vascular function in autoimmune rheumatic diseases: a systematic review and meta-analysis., Rheumatology (Oxford), Vol: 60, Pages: 3107-3120

OBJECTIVES: To summarize existing evidence and quantify the effects of physical activity on vascular function and structure in autoimmune rheumatic diseases (ARDs). METHODS: Databases were searched (through March 2020) for clinical trials evaluating the effects of physical activity interventions on markers of micro- and macrovascular function and macrovascular structure in ARDs. Studies were combined using random effects meta-analysis, which was conducted using Hedges' g. Meta-analyses were performed on each of the following outcomes: microvascular function [i.e. skin blood flow or vascular conductance responses to acetylcholine (ACh) or sodium nitropusside (SNP) administration]; macrovascular function [i.e. brachial flow-mediated dilation (FMD%) or brachial responses to glyceryl trinitrate (GTN%); and macrovascular structure [i.e. aortic pulse wave velocity (PWV)]. RESULTS: Ten studies (11 trials) with a total of 355 participants were included in this review. Physical activity promoted significant improvements in microvascular [skin blood flow responses to ACh, g = 0.92 (95% CI 0.42, 1.42)] and macrovascular function [FMD%, g = 0.94 (95% CI 0.56, 1.02); GTN%, g = 0.53 (95% CI 0.09, 0.98)]. Conversely, there was no evidence for beneficial effects of physical activity on macrovascular structure [PWV, g = -0.41 (95% CI -1.13, 0.32)]. CONCLUSIONS: Overall, the available clinical trials demonstrated a beneficial effect of physical activity on markers of micro- and macrovascular function but not on macrovascular structure in patients with ARDs. The broad beneficial impact of physical activity across the vasculature identified in this review support its role as an effective non-pharmacological management strategy for patients with ARDs.

Journal article

Peçanha T, de Brito LC, Fecchio RY, de Sousa PN, Silva ND, Couto PG, de Abreu AP, da Silva GV, Mion D, Low DA, de Moraes Forjaz CLet al., 2021, Activation of Mechanoreflex, but not Central Command, Delays Heart Rate Recovery after Exercise in Healthy Men., Int J Sports Med, Vol: 42, Pages: 602-609

This study tested the hypotheses that activation of central command and muscle mechanoreflex during post-exercise recovery delays fast-phase heart rate recovery with little influence on the slow phase. Twenty-five healthy men underwent three submaximal cycling bouts, each followed by a different 5-min recovery protocol: active (cycling generated by the own subject), passive (cycling generated by external force) and inactive (no-cycling). Heart rate recovery was assessed by the heart rate decay from peak exercise to 30 s and 60 s of recovery (HRR30s, HRR60s fast phase) and from 60 s-to-300 s of recovery (HRR60-300s slow phase). The effect of central command was examined by comparing active and passive recoveries (with and without central command activation) and the effect of mechanoreflex was assessed by comparing passive and inactive recoveries (with and without mechanoreflex activation). Heart rate recovery was similar between active and passive recoveries, regardless of the phase. Heart rate recovery was slower in the passive than inactive recovery in the fast phase (HRR60s=20±8vs.27 ±10 bpm, p<0.01), but not in the slow phase (HRR60-300s=13±8vs.10±8 bpm, p=0.11). In conclusion, activation of mechanoreflex, but not central command, during recovery delays fast-phase heart rate recovery. These results elucidate important neural mechanisms behind heart rate recovery regulation.

Journal article

Callovini A, Fornasiero A, Savoldelli A, Stella F, Low DA, Pellegrini B, Schena F, Bortolan Let al., 2021, Effects of three-exercise sessions in the heat on endurance cycling performance, JOURNAL OF THERMAL BIOLOGY, Vol: 98, ISSN: 0306-4565

Journal article

Roberts KA, Draijer R, Hopkins ND, de Graaf Y, Holder SM, Carter SE, Thijssen DHJ, Low DAet al., 2021, Impact of green tea on the deleterious cardiometabolic effects of 7-days unhealthy lifestyle in young healthy males, PHYSIOLOGICAL REPORTS, Vol: 9, ISSN: 2051-817X

Journal article

Fornasiero A, Savoldelli A, Stella F, Callovini A, Bortolan L, Zignoli A, Low DA, Mourot L, Schena F, Pellegrini Bet al., 2021, Response to Chaen and Trapellieni re: "Shortening Work-Rest Durations Reduces Physiological and Perceptual Load During Uphill Walking in Simulated Cold High-Altitude Conditions," by Fornasiero et al., High Alt Med Biol, Vol: 22, Pages: 105-106

Journal article

Brislane Á, Jones H, Holder SM, Low DA, Hopkins NDet al., 2021, The Effect of Exercise During Pregnancy on Maternal and Offspring Vascular Outcomes: a Pilot Study., Reprod Sci, Vol: 28, Pages: 510-523

The aim of this pilot study is to obtain estimates for the change in maternal cerebrovascular (primary) and offspring vascular structure (secondary) during healthy pregnancy that includes structured exercise. Eighteen pregnant women self-assigned to a moderate-intensity aerobic exercise intervention or a control group. Maternal cerebral blood flow (CBF) at the middle cerebral artery, cerebro- and peripheral-vascular function was assessed at the end of each trimester. Offspring carotid artery intima-media thickness (IMT) was measured within 12 weeks of birth. For exploratory purposes, we performed statistical analysis to provide estimates of the change for primary and secondary outcome variables. Maternal CBF reduced (- 8 cm s-1 [- 14 to - 2]) with evidence of change to cerebral autoregulation (normalised gain: 0.12 %cm s-1% mmHg-1mmHg/% [- 0.18 to 0.40]) during pregnancy. Offspring carotid IMT was smaller in the exercise group (- 0.04 mm [- 0.12-0.03]) compared with controls. Based upon this data, a sample size of 33 and 57 in each group is required for low-frequency normalised gain and offspring IMT, respectively. This would provide 90% power to detect statistically significant (P < 0.05) between group differences in a randomised controlled trial. CBF is reduced in pregnancy, possibly due to reduced vascular resistance and altered maternal cerebral autoregulation. Maternal exercise had negligible effects on cerebrovascular adaptation to pregnancy, but we observed lower offspring carotid artery wall thickness following maternal exercise. Our directional findings and sample size estimations should be explored in a fully powered randomised control trial.Clinical trial registration: The trial was registered on March 14th at https://register.clinicaltrials.gov (NCT03079258). Participant enrolment began on 3rd April 2016.

Journal article

Speretta GF, Fornasiero A, Johns JA, Hopkins N, Thijssen DH, Low DAet al., 2021, Effects of Breaking up Deskwork with Physical Activity Combined with Tea Consumption on Cerebrovascular Function, Mood, and Affect, International Journal of Cardiovascular Sciences, Vol: 34, Pages: 644-653, ISSN: 2359-4802

Background: Prolonged sitting, typical of desk work, decreases cerebral blood flow (CBF), mood and affect. Conversely, short physical activity breaks from sitting may prevent these detrimental effects and provide cardiometabolic benefits. Objective: We evaluated the effect of interrupting prolonged sitting with short breaks of light physical activity combined with tea consumption on CBF, cerebral autoregulation (CA), mood, and affect in desk workers. Methods: Nineteen healthy desk workers (ten male, 27±10 years) performed desk work in a laboratory for six hours on two separate intervention days: tea breaks (TEA-BREAK: short walk combined with ingestion of one cup of tea every hour) and sedentary (SED: ingestion of one cup of water every hour, while seated). Before and after desk work, we assessed mean arterial pressure (MAP), middle cerebral artery blood velocity (MCAv) and CA. Questionnaires were used to assess mood (Bond & Lader, PANAS) and affect (Affect grid) before and after the intervention. Data are expressed as mean ± standard deviation. Two-way ANOVA with repeated measurements followed by Sidak post hoc test was used for data analysis. Paired Student’s t-test was also used to compare changes (∆) between trials. Statistical significance was at p<0.05. Results: Desk work increased MAP (4.6±4.6 ∆ mmHg; P<0.05), and decreased MCAv (-5.2±7.0 ∆ cm/s; P<0.05), with no difference between interventions in these parameters. TEA-BREAKS, but not SED, decreased gain (-0.08±0.12 ∆ cm.s-1. mmHg.-1) and increased phase (5.26±8.84 ∆ radians) at very low frequency (P<0.05), but not at low frequency. Small changes in positive affect were found after the six hours of desk work (-5.5±7.3 ∆ scale; P<0.05), with no differences between interventions. Conclusion: Changes in MCAv and positive affect induced by prolonged desk work could not be prevented by TEA-BREAKS. However, TEA-BREAKS improved CA, suggesting

Journal article

Morris AS, Murphy RC, Hopkins ND, Low DA, Healy GN, Edwardson CL, Collins B, Timpson H, Shepherd SO, Cochrane M, Gavin D, Graves LEFet al., 2021, Sit Less and Move More-A Multicomponent Intervention With and Without Height-Adjustable Workstations in Contact Center Call Agents: A Pilot Randomized Controlled Trial., J Occup Environ Med, Vol: 63, Pages: 44-56

OBJECTIVE: To pilot a multicomponent intervention to sit less and move more, with (SLAMM+) and without (SLAMM) height-adjustable workstations, in contact center call agents. METHODS: Agents were individually randomized to SLAMM or SLAMM+ in this 10-month, parallel, open-label, pilot trial. Mixed-methods assessed response, recruitment, retention, attrition and completion rates, adverse effects, trial feasibility and acceptability, preliminary effectiveness on worktime sitting, and described secondary outcomes. RESULTS: The participant recruitment rate, and randomization, data collection, and interventions were mostly acceptable. Refinements to organization recruitment were identified. High staff turnover negatively impacted retention and completion rates. The multicomponent intervention with height-adjustable workstations has potential to reduce sitting time at work. CONCLUSIONS: The demonstrated findings will help prepare for a future randomized controlled trial designed to assess the effect of the interventions.

Journal article

Barton TJ, Low DA, Bakker EA, Janssen T, de Groot S, van der Woude L, Thijssen DHJet al., 2021, Traditional Cardiovascular Risk Factors Strongly Underestimate the 5-Year Occurrence of Cardiovascular Morbidity and Mortality in Spinal Cord Injured Individuals., Arch Phys Med Rehabil, Vol: 102, Pages: 27-34

OBJECTIVES: To explore whether traditional models of cardiovascular disease (CVD) risk prediction correctly predict CVD events across a median 5.7-year follow-up period in individuals with spinal cord injury (SCI) and whether adding SCI-related characteristics (ie, lesion level) to the prediction model can improve the prognostic value. DESIGN: Retrospective analysis of patient records. SETTING: Observation at the start of active rehabilitation of participants in a multicenter cohort study, "Restoration of (Wheelchair) Mobility in SCI Rehabilitation," in the Netherlands. PARTICIPANTS: Patients with SCI (N=200) The patients were 74% men, aged 40±14 years, and with an American Spinal Injury Association (ASIA) impairment score of A through D. Forty percent had tetraplegia, and 69% were motor complete. INTERVENTIONS: Risk profiling/not applicable. MAIN OUTCOME MEASURES: Survival status and cardiovascular morbidity and mortality qwere obtained from medical records. Five-year Framingham Risk Scores (FRS) and the FRS ability to predict events assessed using receiver operating characteristic (ROC) curves with corresponding areas under the curve (AUC) and 95% confidence intervals (CI). Kaplan-Meier curves and the log-rank test were used to assess the difference in clinical outcome between participants with an FRS score lower or higher than the median FRS score for the cohort. SCI-related factors associated with CVD events, ASIA impairment, motor completeness, level of injury, and sports participation before injury were explored using univariate and multivariate Cox proportional hazard regression. RESULTS: The median 5-year FRS was 1.36%. Across a median follow-up period of 5.7 years, 39 developed a CVD event, including 10 fatalities. Although the FRS markedly underestimated the true occurrence of CVD events, the Kaplan-Meier curves and the log-rank test showed that the risk ratio for individuals with an FRS score less than the median FRS (eg, low risk) versus

Journal article

Kleinnibbelink G, Stens NA, Fornasiero A, Speretta GF, Van Dijk APJ, Low DA, Oxborough DL, Thijssen DHJet al., 2020, The acute and chronic effects of high-intensity exercise in hypoxia on blood pressure and post-exercise hypotension: A randomized cross-over trial., Medicine (Baltimore), Vol: 99

BACKGROUND: Acute exercise leads to an immediate drop in blood pressure (BP), also called post-exercise hypotension (PEH). Exercise in hypoxia is related to additional vasodilation, potentially contributing to more profound PEH. Therefore, we investigated the impact of hypoxia versus normoxia on the magnitude of PEH. Second, we examined whether these changes in PEH relate to the BP-lowering effects of 12-week exercise training under hypoxia. METHODS: In this prospective study, 21 healthy individuals (age 22.2 ± 3.0 years, 14 male) performed a 45-minute high-intensity running exercise on 2 different days in a random order, under hypoxia (fraction of inspired oxygen 14.5%) and normoxia (fraction of inspired oxygen 20.9%). BP was examined pre-exercise (t = 0) and at t = 15, t = 30, t = 45, and t = 60 minutes post-exercise. Afterward, subjects took part in a 12-week hypoxic running exercise training program. Resting BP was measured before and after the 12-week training program. RESULTS: Acute exercise induced a significant decrease in systolic BP (systolic blood pressure [SBP], P = .001), but not in diastolic BP (diastolic blood pressure [DBP], P = .113). No significant differences were observed in post-exercise BP between hypoxic and normoxic conditions (SBP, P = .324 and DBP, P = .204). Post-exercise changes in SBP, DBP, and mean arterial pressure significantly correlated to the 12-week exercise training-induced changes in SBP (r = 0.557, P = .001), DBP (r = 0.615, P < .001), and mean arterial pressure (r = 0.458, P = .011). CONCLUSION: Our findings show that hypoxia does not alter the magnitude of PEH in healthy individuals, whilst PEH relates to the BP-lowering effects of exercise. These data highlight the strong link between acute and chronic changes in BP.

Journal article

Fornasiero A, Savoldelli A, Stella F, Callovini A, Bortolan L, Zignoli A, Low DA, Mourot L, Schena F, Pellegrini Bet al., 2020, Shortening Work-Rest Durations Reduces Physiological and Perceptual Load During Uphill Walking in Simulated Cold High-Altitude Conditions., High Alt Med Biol, Vol: 21, Pages: 249-257

Fornasiero, Alessandro, Aldo Savoldelli, Federico Stella, Alexa Callovini, Lorenzo Bortolan, Andrea Zignoli, David A. Low, Laurent Mourot, Federico Schena, and Barbara Pellegrini. Shortening work-rest durations reduces physiological and perceptual load during uphill walking in simulated cold high-altitude conditions. High Alt Med Biol. 21:249-257, 2020. Background: We investigated the effects of two different work-rest durations on the physiological and perceptual responses to a simulated mountain hike in a cold hypoxic environment. Materials and Methods: Twelve healthy nonacclimatized active men (age 31.3 ± 5.3 years, body mass index 22.4 ± 1.5 kg/m2) completed a 80-minute work-matched intermittent exercise on a motorized treadmill (25% incline, fixed self-selected speed), in a simulated mountain environment (-25°C, FiO2 = 11%, ≈5000 m a.s.l.), wearing extreme cold weather gear, once with short (20 × 3 minutes walking with 1 minute rest; SHORT) and once with long (10 × 6 minutes walking with 2 minutes rest; LONG) work-rest durations. Heart rate (HR), pulse oxygen saturation (SpO2), rate of perceived exertion (RPE), and thermal sensation (TS) were assessed throughout the exercise protocols. Cardiac autonomic modulation was assessed before (PRE) and after exercise (POST) in supine position, as well as during standing resting periods by means of HR recovery (HRR) assessment. Results: SpO2 and TS were similar (p > 0.05) in SHORT and LONG protocols. HR and RPE were increased, and HRR reduced during LONG compared to SHORT (p < 0.05). Parasympathetic activity indices were reduced at POST after both protocols (p < 0.05), but to a lesser extent after SHORT (p < 0.05). Conclusions: Reduced work-rest durations are associated with improved perceptual responses and less perturbation of cardiac

Journal article

Mullington CJ, Low DA, Strutton PH, Malhotra Set al., 2020, A mechanistic study of the tremor associated with epidural anaesthesia for intrapartum caesarean delivery, International Journal of Obstetric Anesthesia, Vol: 43, Pages: 56-64, ISSN: 0959-289X

BackgroundIt is not known if the tremor associated with an epidural top-up dose for intrapartum caesarean delivery is thermoregulatory shivering. A tremor is only shivering if it has the same frequency profile as cold stress-induced shivering. Thermoregulatory shivering is a response to a reduction in actual body temperature, whereas non-thermoregulatory shivering may be triggered by a reduction in sensed body temperature. This mechanistic study aimed to compare: 1. the frequency profiles of epidural top-up tremor and cold stress-induced shivering; and 2. body temperature (actual and sensed) before epidural top-up and at the onset of tremor.MethodsTwenty obstetric patients received an epidural top-up for intrapartum caesarean delivery and 20 non-pregnant female volunteers underwent a cold stress. Tremor, surface electromyography, core temperature, skin temperature (seven sites) and temperature sensation votes (a bipolar visual analog score ranging from −50 to +50 mm) were recorded.ResultsThe mean (SD) primary oscillation (9.9 (1.9) Hz) frequency of epidural top-up tremor did not differ from that of cold stress-induced shivering (9.0 (1.6) Hz; P=0.194), but the mean (SD) burst frequency was slower (6.1 (1.2) × 10−2 Hz vs 6.9 (0.7) × 10−2 Hz, respectively; P=0.046). Before the epidural top-up dose, the mean (SD) core temperature was 37.6 (0.6) °C. Between the epidural top-up dose and the onset of tremor the mean (SD) core temperature did not change (–0.1 (0.1) °C; P=0.126), the mean (SD) skin temperature increased (+0.4 (0.4) °C; P=0.002) and the mean (SD) temperature sensation votes decreased (−12 (16) mm; P=0.012).ConclusionThese results suggest that epidural top-up tremor is a form of non-thermoregulatory shivering triggered by a reduction in sensed body temperature.

Journal article

Mawhinney C, Heinonen I, Low DA, Han C, Jones H, Kalliokoski KK, Kirjavainen A, Kemppainen J, Di Salvo V, Weston M, Cable T, Gregson Wet al., 2020, Changes in quadriceps femoris muscle perfusion following different degrees of cold-water immersion, JOURNAL OF APPLIED PHYSIOLOGY, Vol: 128, Pages: 1392-1401, ISSN: 8750-7587

Journal article

Thomas SD, Carter HH, Jones H, Thijssen DHJ, Low DAet al., 2020, Effects of Acute Exercise on Cutaneous Thermal Sensation, INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH, Vol: 17

Journal article

Peçanha T, Low D, de Brito LC, Fecchio RY, de Sousa PN, da Silva-Júnior ND, de Abreu AP, da Silva GV, Mion-Junior D, Forjaz CLDMet al., 2020, Effects of postexercise cooling on heart rate recovery in normotensive and hypertensive men., Clin Physiol Funct Imaging, Vol: 40, Pages: 114-121

BACKGROUND: Postexercise heart rate recovery (HRR) is determined by cardiac autonomic restoration after exercise and is reduced in hypertension. Postexercise cooling accelerates HRR in healthy subjects, but its effects in a population with cardiac autonomic dysfunction, such as hypertensives (HT), may be blunted. This study assessed and compared the effects of postexercise cooling on HRR and cardiac autonomic regulation in HT and normotensive (NT) subjects. METHODS: Twenty-three never-treated HT (43 ± 8 years) and 25 NT (45 ± 8 years) men randomly underwent two exercise sessions (30 min of cycling at 70% VO2peak ) followed by 15 min of recovery. In one randomly allocated session, a fan was turned on in front of the subject during the recovery (cooling), while in the other session, no cooling was performed (control). HRR was assessed by heart rate reductions after 60 s (HRR60s) and 300 s (HRR300s) of recovery, short-term time constant of HRR (T30) and the time constant of the HRR after exponential fitting (HRRτ). HRV was assessed using time- and frequency-domain indices. RESULTS: HRR and HRV responses in the cooling and control sessions were similar between the HT and NT. Thus, in both groups, postexercise cooling equally accelerated HRR (HRR300s = 39±12 versus 36 ± 10 bpm, P≤0·05) and increased postexercise HRV (lnRMSSD = 1·8 ± 0·7 versus 1·6 ± 0·7 ms, P≤0·05). CONCLUSION: Differently from the hypothesis, postexercise cooling produced similar improvements in HRR in HT and NT men, likely by an acceleration of cardiac parasympathetic reactivation and sympathetic withdrawal. These results suggest that postexercise cooling equally accelerates HRR in hypertensive and normotensive subjects.

Journal article

Brislane Á, Low DA, Carter SE, Holder SM, Jones H, Hopkins NDet al., 2020, Cerebral and peripheral vascular differences between pre- and postmenopausal women., Menopause, Vol: 27, Pages: 170-182

OBJECTIVE: Menopause is associated with lower peripheral vascular function; however, cerebrovascular responses to this time-period are unclear. We aimed to describe peripheral vascular and cerebrovascular differences between pre- and postmenopausal women. METHODS: Fifty pre- and postmenopausal women (N = 100) underwent assessments of cerebral blood flow; cerebrovascular reactivity and autoregulation; carotid artery reactivity; brachial and femoral artery flow-mediated dilation; and carotid, brachial, and femoral artery intima-media thickness. Comparisons were made between pre- and postmenopausal women followed by a secondary analysis (N = 20) between late premenopausal women and those within 5 years of menopause using a general linear model. RESULTS: Cerebral blood flow (-11 [-17, -4 cm/s]; P = 0.03) and carotid reactivity (-2.3 [-4.3, -0.3%] P = 0.03) were lower postmenopause compared to premenopause, whereas cerebrovascular reactivity and autoregulation did not differ (P > 0.05). Postmenopausal women had a larger carotid (0.16 [0.13, 0.20 mm] P < 0.001), brachial (0.07 [0.03, 0.11 mm] P = 0.004), and femoral artery intima-media thickness (0.09 [0.05, 0.14 mm] P = 0.04), alongside lower brachial (-2.3 [-3.9, -0.7%] P = 0.004) and femoral artery flow-mediated dilation (-3.0 [-4.3, -1.8%] P < 0.001). In the secondary-analysis, early postmenopausal women had a lower femoral artery flow-mediated dilation (-1.9 [-3.9, -0.0%] P = 0.05) and larger carotid intima-media thickness (0.07 [0.00, 0.14 mm] P = 0.03) compared to late premenopausal women. CONCLUSIONS: Cerebral blood flow, carotid artery reactivity, peripheral vascular function, and structure are negatively affected by age. Preliminary data indicate that femoral artery function and carotid artery structure may be potentially impaired in early postmenopause compared with late premenopause. These findings suggest that conduit arteries susceptible to atherosclerosis may be important targets for lifestyle inte

Journal article

Low DA, Jones H, Cable NT, Alexander LM, Kenney WLet al., 2020, Historical reviews of the assessment of human cardiovascular function: interrogation and understanding of the control of skin blood flow, EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY, Vol: 120, Pages: 1-16, ISSN: 1439-6319

Journal article

Jones H, Bailey TG, Barr DA, France M, Lucas RAI, Crandall CG, Low DAet al., 2019, Is core temperature the trigger of a menopausal hot flush?, MENOPAUSE-THE JOURNAL OF THE NORTH AMERICAN MENOPAUSE SOCIETY, Vol: 26, Pages: 1016-1023, ISSN: 1072-3714

Journal article

This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.

Request URL: http://wlsprd.imperial.ac.uk:80/respub/WEB-INF/jsp/search-html.jsp Request URI: /respub/WEB-INF/jsp/search-html.jsp Query String: respub-action=search.html&id=00616153&limit=30&person=true