Obesity is characterised by excess adipose tissue, which impairs vascular function and blood pressure (BP) regulation. However, it remains unclear whether adiposity influences the BP-lowering response to isometric exercise training (IET). This randomised-controlled trial explored the impact of body mass index on BP and cardiovascular adaptation following IET. 80 participants with normal to high-normal systolic BP (range 120-140 mmHg) were recruited for the study. Participants were randomised into two BMI groups: normal BMI (18.5–24.9 kg/m²; n=40) and high BMI (25-34.9 kg/m²; n=40) and then either performed home-based lower-body IET, 3 times per week, for 4 weeks (each session comprised 4 x 2-minute bouts), or were allocated to the control group. Cardiovascular variables, including BP, total peripheral resistance (TPR), and heart rate variability (HRV), were measured at rest pre- and post-intervention. Overall, there were significant reductions in systolic BP, diastolic BP and mean arterial pressure (MAP) in the IET group compared to control. However, the normal-BMI group had significantly greater reductions in diastolic BP (– 8.5 [– 11.8, – 5.3] mmHg) and MAP (– 9.2 [– 11.9, – 6.6] mmHg) compared to the high-BMI group (dBP: – 2.6 [– 6.2, 1.1]; MAP: -4.7 [– 7.6, – 1.8]). Although TPR was significantly greater in the high-BMI group at week 4 (p=0.022), it was also elevated at baseline, and change-score analyses revealed no significant between-group difference in the magnitude of TPR reduction (Δ p=0.964). These findings indicate that BMI may modulate the BP-lowering response to IET, suggesting that individuals with higher BMI may require adjunctive or prolonged interventions to optimise BP reduction.

An elevation in resting venous blood lactate ([La − ] b ) levels in conditions of myocardial hypoperfusion is associated with adverse prognosis and survival. This investigation aimed to assess changes in venous [La − ] b levels induced by dobutamine stress in the presence and absence of myocardial ischaemia and adverse outcomes at 1 year. Four hundred and four consecutive patients (mean age 70 ± 10 years, 243 male) reporting chest pain underwent dobutamine stress echocardiography (DSE) and were categorised as ischaemic (IS) or non‐ischaemic (NI) responders. Conventional and global longitudinal strain (GLS) echocardiographic measures were recorded at rest. Venous [La − ] b samples were acquired at rest, peak stress and 1, 3, 5 and 10 min into recovery using a commercially available Lactate Pro 2 device. There were no significant differences in [La − ] b concentrations between IS (1.75 ± 0.76 mmol L −1 ) and NI (1.73 ± 0.60 mmol L −1 ) responders at baseline ( P = 0.592). However, [La − ] b concentrations were significantly greater at peak stress (1.83 ± 0.57 vs. 1.68 ± 0.60 mmol L −1 ), 1 (1.90 ± 0.56 vs. 1.73 ± 0.71 mmol L −1 ), 3 (1.97 ± 0.56 vs. 1.73 ± 0.71 mmol L −1 ), 5 (1.98 ± 0.60 vs. 1.74 ± 0.70 mmol L −1 ) and 10 min (2.01 ± 0.63 vs. 1.76 ± 0.71 mmol L −1 ) into recovery between IS and NI responders (all P < 0.001). GLS was significantly lower in IS compared to NI (−15.5 ± 2.9 vs. −16.2% ± 2.7%, P = 0.02) responders at baseline. In patients who experienced an adverse cardiac event during 1 year of follow‐up, GLS (−14.4 ± 2.7 vs. −16.1% ± 2.8%, P < 0.001) and [La − ] b concentrations were significantly lower at baseline (1.54 ± 0.55 vs. 1.78 ± 0.70 mmol L −1 , P = 0.02), as were [La − ] b concentrations at 5 (1.68 ± 0.55 vs. 1.88 ± 0.68 mmol L −1 , P = 0.04) and 10 min (1.70 ± 0.56 vs. 1.93 ± 0.71 mmol L −1 , P = 0.02) into recovery compared to patients who did not experience an adverse event. GLS (hazard ration (HR) 1.21; 95% CI: 1.11–1.33, P < 0.001) and [La − ] b concentrations at 10 min into recovery (HR 0.54; 95% CI: 0.33–0.85, P = 0.01) were significant independent predictors of an adverse event. Transient myocardial ischaemia is associated with a significant elevation in [La − ] b concentrations, which extends into the recovery period, compared to NI responders. A blunted metabolic response to dobutamine stress and attenuated longitudinal myocardial mechanics are independently associated with short‐term adverse events.

BACKGROUND: Hypertension affects 1:4 adults and increases the risk of CV disease. Management aims to reduce blood pressure to a level that minimizes risk; up to 50% of people don't achieve blood pressure targets often due to insufficient treatment or poor adherence. Exercise has a role to play in the management of hypertension. The impact of isometric exercise on hypertension in healthcare settings is poorly understood. METHODS: Randomized controlled open-label multicentre feasibility study of isometric exercise compared to standard care in unmedicated hypertensives. Participants received an individualised isometric wall squat prescription and performed 4 x 2-minute bouts thrice weekly for 6-months. We assessed recruitment, deliverability, attrition, adherence, and variance in blood pressure change. RESULTS: 41 participants (56 +/- 15 years), 59% women, were randomized. Isometric exercise was found to be easily deliverable to all participants. At 6-months 34% withdrew, of those who completed isometric exercise 87% of their sessions were at the correct intensity. Variance in blood pressure change was 14.4 mmHg. The study was not powered to show a difference in blood pressure between groups, however blood pressure reductions were seen in the intervention group at all study time points compared to baseline. CONCLUSIONS: The results have allowed us to calculate a sample size (n=542) for a full randomised controlled trial. The results demonstrate good acceptability and adherence rates to the treatment protocol. Our results show a signal towards a consistent systolic blood pressure reduction in the isometric exercise group compared to baseline. REGISTRATION: NCT04936022 https://classic.clinicaltrials.gov/ct2/show/NCT04936022cond=isometric+exercise&draw=2&rank=7 Registry Identifier: ISRCTN:13472393

AbstractThe effects of triathlon exercise on cardiac function are well documented. While Olympic triathlon (swim‐bike‐run) remains the standard format, increasing concerns about water quality in natural waterways present ongoing challenges for open‐water swimming events, highlighting the potential need to consider alternative formats such as duathlon (run‐bike‐run) in some circumstances. An additional run may increase the overall metabolic and cardiovascular demand compared with the swim in triathlon, leading to reduced future performance. Conversely, the majority of EICF research reports reversal of post‐exercise perturbations within 24–7 days of recovery but duathlon has not yet been studied in this context. Therefore, this study aimed to investigate the cardiac, autonomic, haemodynamic and biomarker responses during and following two Olympic distance (OD) duathlon separated by 7 days of recovery. Highly‐trained (V O2max >60 mL·kg−1·min−1) male participants (n = 10) completed two lab‐based OD duathlons, either continuous (BD) or with functional measurements after each leg (UD), separated by 7 days of rest. Conventional echocardiography recorded standard and tissue Doppler measures of left ventricular (LV) structure and function. Speckle tracking echocardiography was used to measure global longitudinal strain (GLS). Time and frequency domain analysis of HRV, as well as plasma high sensitivity cardiac troponin T (hs‐cTnT) were measured pre and post exercise. In the broken duathlon trial (BD) cardiac measurements and blood samples were also taken between each leg. In the unbroken duathlon (UD) participants performed each leg sequentially. Duathlon exercise resulted in similar cardiac functional and biomarker alterations as previously reported in triathlon and standalone running and cycling exercise. Cardiac troponins were still elevated following 24 h−1 of recovery. However, functional changes were resolved within 24 h−1 of passive recovery and did not impair subsequent duathlon performance, or pre‐exercise measurements 7 days after the first trial. Whether or not elite or recreational athletes experience the same magnitude and reversibility of these changes remains to be elucidated further.

Objective: Isometric exercise training (IET) is consistently shown to reduce blood pressure (BP). We recently investigated the feasibility of delivering a personalised isometric wall-squat protocol to patients with Stage-1 hypertension within a free-to-access healthcare setting. Whist healthcare professionals (HCP) and patients thought the intervention was feasible, any exercise prescription requiring HCP input and specific resource allocation was not deemed viable. This study aimed to examine the effect of a low resource IET prescription using rating of perceived exertion (RPE) versus HCP prescription and control group upon BP. Design and method: 30 participants with normal to high-normal BP were randomised into either a (heart rate) HR-Exercise (HR-EX), RPE-Exercise (RPE-EX) or control (CON) group. IET groups undertook a 4-week home-based wall-squat programme with intensity prescribed either directly by a HCP using our established HR method (HR-EX), or self-prescribed using a RPE selection protocol (RPE-EX). The CON group maintained their normal lifestyle. Clinic BP was measured at baseline and post-IET. Results: Clinic systolic (SBP) and diastolic (DBP) were significantly reduced (p < 0.001) in both intervention groups following IET compared to baseline. Group mean reductions for the HR-EX (SBP: -14 ± 6, DBP: -6 ± 4 mmHg) and RPE-EX (SBP: -9 ± 6, DBP: -6 ± 4 mmHg) were greater (p < 0.001) than CON (no differences) group. There were no differences between intervention groups in the magnitude of the BP reductions; however, at baseline HR-EX had greater SBP (p < 0.001) results compared to RPE-EX, but following the IET there were no significant differences between these groups. Conclusions: RPE prescribed wall-squat IET provides an efficacious method for reducing BP at home, delivering reductions comparable to the HR-based prescription method. This new RPE-based method, developed because of difficulties in delivering IET prescription in a general healthcare setting, demonstrates great potential as an effective lifestyle intervention to lower BP mainly due to improved access. It requires minimal resource to deliver and implement in any environment and could be provided entirely online.

OBJECTIVE:To perform a large-scale pairwise and network meta-analysis on the effects of all relevant exercise training modes on resting blood pressure to establish optimal antihypertensive exercise prescription practices. DESIGN:Systematic review and network meta-analysis. DATA SOURCES:PubMed (Medline), the Cochrane library and Web of Science were systematically searched. ELIGIBILITY CRITERIA:Randomised controlled trials published between 1990 and February 2023. All relevant work reporting reductions in systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) following an exercise intervention of ≥2 weeks, with an eligible non-intervention control group, were included. RESULTS:270 randomised controlled trials were ultimately included in the final analysis, with a pooled sample size of 15 827 participants. Pairwise analyses demonstrated significant reductions in resting SBP and DBP following aerobic exercise training (-4.49/-2.53 mm Hg, p<0.001), dynamic resistance training (-4.55/-3.04 mm Hg, p<0.001), combined training (-6.04/-2.54 mm Hg, p<0.001), high-intensity interval training (-4.08/-2.50 mm Hg, p<0.001) and isometric exercise training (-8.24/-4.00 mm Hg, p<0.001). As shown in the network meta-analysis, the rank order of effectiveness based on the surface under the cumulative ranking curve (SUCRA) values for SBP were isometric exercise training (SUCRA: 98.3%), combined training (75.7%), dynamic resistance training (46.1%), aerobic exercise training (40.5%) and high-intensity interval training (39.4%). Secondary network meta-analyses revealed isometric wall squat and running as the most effective submodes for reducing SBP (90.4%) and DBP (91.3%), respectively. CONCLUSION:Various exercise training modes improve resting blood pressure, particularly isometric exercise. The results of this analysis should inform future exercise guideline recommendations for the prevention and treatment of arterial hypertension.

AbstractIsometric exercise training (IET) is an effective intervention for the management of resting blood pressure (BP). However, the effects of IET on arterial stiffness remain largely unknown. Eighteen unmedicated physically inactive participants were recruited. Participants were randomly allocated in a cross‐over design to 4 weeks of home‐based wall squat IET and control period, separated by a 3‐week washout period. Continuous beat‐to‐beat hemodynamics, including early and late systolic (sBP 1 and sBP 2, respectively) and diastolic blood pressure (dBP) were recorded for a period of 5 min and waveforms were extracted and analyzed to acquire the augmentation index (AIx) as a measure of arterial stiffness. sBP 1 (−7.7 ± 12.8 mmHg, p = 0.024), sBP 2 (−5.9 ± 9.9 mmHg, p = 0.042) and dBP (−4.4 ± 7.2 mmHg, p = 0.037) all significantly decreased following IET compared to the control period. Importantly, there was a significant reduction in AIx following IET (−6.6 ± 14.5%, p = 0.02) compared to the control period. There were also adjacent significant reductions in total peripheral resistance (−140.7 ± 65.8 dynes·cm‐5, p = 0.042) and pulse pressure (−3.8 ± 4.2, p = 0.003) compared to the control period. This study demonstrates an improvement in arterial stiffness following a short‐term IET intervention. These findings have important clinical implications regarding cardiovascular risk. Mechanistically, these results suggest that reductions in resting BP following IET are induced via favorable vascular adaptations, although the intricate details of such adaptations are not yet clear.

Purpose Isometric exercise (IE) and isometric wall squat (IWS) training have been shown to be effective methods of reducing arterial blood pressure. However, most IE interventions require methodologies and equipment that could present a barrier to participation. Therefore, this study aimed to examine the effectiveness of an accessible RPE prescribed IWS intervention. Methods Thirty normotensive and pre-hypertensive adults were randomly assigned to a control group or one of two 4-week home-based IWS intervention groups: the first group conducted IWS exercise where intensity was prescribed and monitored using RPE (RPE-EX), whilst the other used a previously validated HR prescription method (HR-EX). Resting and ambulatory heart rate (HR) and blood pressure (BP) were measured pre- and post-intervention. Results Minimum clinically important differences (MCID; − 5 mmHg) in SBP and/or DBP were shown in 100% of intervention participants. Statistically significant reductions were shown in resting seated BP (RPE-EX: SBP: − 9 ± 6, DBP: − 6 ± 4, MAP: − 6 ± 3 mmHg; HR-EX: SBP: − 14 ± 6, DBP: − 6 ± 4, MAP: − 8 ± 4 mmHg), supine BP (RPE-EX: SBP: − 8 (− 5), DBP: − 8 (− 7), MAP: − 8 (− 4) mmHg; HR-EX: SBP: − 5 (− 4), MAP − 5 (− 4) mmHg), and ambulatory SBP (RPE-EX: − 8 ± 6 mmHg; HR-EX: − 10 ± 4 mmHg) following the interventions. There were no statistically significant differences between intervention groups in the magnitude of BP reduction. Conclusion RPE prescribed IWS exercise can provide an effective and more accessible method for reducing BP at home, providing reductions comparable to the current HR-based prescription method.

The COVID-19 pandemic has significantly impacted on the delivery of clinical trials in the UK, posing complicated organisational challenges and requiring adaptations, especially to exercise intervention studies based in the community. We aim to identify the challenges of public involvement, recruitment, consent, follow-up, intervention and the healthcare professional delivery aspects of a feasibility study of exercise in hypertensive primary care patients during the COVID-19 pandemic. While these challenges elicited many reactive changes which were specific to, and only relevant in the context of ‘lockdown’ requirements, some of the protocol developments that came about during this unprecedented period have great potential to inform more permanent practices for carrying out this type of research. To this end, we detail the necessary adaptations to many elements of the feasibility study and critically reflect on our approach to redesigning and amending this ongoing project in order to maintain its viability to date. Some of the more major protocol adaptations, such as moving the study to remote means wherever possible, had further unforeseen and undesirable outcomes (eg, additional appointments) with regards to extra resources required to deliver the study. However, other changes improved the efficiency of the study, such as the remote informed consent and the direct advertising with prescreening survey. The adaptations to the study have clear links to the UK Plan for the future of research delivery. It is intended that this specific documentation and critical evaluation will help those planning or delivering similar studies to do so in a more resource efficient and effective way. In conclusion, it is essential to reflect and respond with protocol changes in the current climate in order to deliver clinical research successfully, as in the case of this particular study.

Abstract Background Optimising exercise prescription in heart failure (HF) with a preserved (HFpEF) or reduced (HFrEF) ejection fraction is clinically important. As such, the aim of this meta-analysis was to compare traditional moderate intensity training (MIT) against combined aerobic and resistance training (CT) and high-intensity interval training (HIIT) for improving aerobic capacity (VO2), as well as other clinically relevant parameters. Methods A comprehensive systematic search was performed to identify randomised controlled trials published between 1990 and May 2021. Research trials reporting the effects of MIT against CT or HIIT on peak VO2 in HFpEF or HFrEF were considered. Left-ventricular ejection fraction (LVEF) and various markers of diastolic function were also analysed. Results Seventeen studies were included in the final analysis, 4 of which compared MIT against CT and 13 compared MIT against HIIT. There were no significant differences between MIT and CT for peak VO2 (weighted mean difference [WMD]: 0.521 ml min−1 kg−1, [95% CI] = − 0.7 to 1.8, P fixed = 0.412) or LVEF (WMD: − 1.129%, [95% CI] = − 3.8 to 1.5, P fixed = 0.408). However, HIIT was significantly more effective than MIT at improving peak VO2 (WMD: 1.62 ml min−1 kg−1, [95% CI] = 0.6–2.6, P random = 0.002) and LVEF (WMD: 3.24%, [95% CI] = 1.7–4.8, P random < 0.001) in HF patients. When dichotomized by HF phenotype, HIIT remained significantly more effective than MIT in all analyses except for peak VO2 in HFpEF. Conclusions HIIT is significantly more effective than MIT for improving peak VO2 and LVEF in HF patients. With the exception of peak VO2 in HFpEF, these findings remain consistent in both phenotypes. Separately, there is no difference in peak VO2 and LVEF change following MIT or CT, suggesting that the addition of resistance exercise does not inhibit aerobic adaptations in HF. Graphical Abstract

More than 30 randomized controlled trials, supported by individual patient-level and group-level meta-analyses and a Delphi analysis of expert opinion, unequivocally show isometric resistance training (IRT) elicits antihypertensive benefits in healthy people and those with chronic illness. We aim to provide efficacy and safety evidence, and a guide for IRT prescription and delivery. Recommendations are made for the use of IRT in specific patient populations and appropriate methods for IRT delivery. Published data suggest IRT consistently elicits mean blood pressure reductions of 7.4/3.3 mmHg systolic blood pressure/diastolic blood pressure, equivalent to antihypertensive medication monotherapy. Blood pressure reductions of this size are associated with an approximate 13% to 22% reduction in major cardiovascular events. Moreover, IRT is safe in a range of patient populations. We suggest that IRT has the greatest potential benefit when used as an antihypertensive therapy in individuals unwilling and/or unable to complete aerobic exercise, or who have had limited adherence or success with it; individuals with resistant or uncontrolled hypertension, already taking at least two pharmacological antihypertensive agents; and healthy or clinical populations, as an adjunct to aerobic exercise and dietary intervention in those who have not yet attained control of their hypertension. IRT is efficacious and produces clinically meaningful blood pressure reductions (systolic blood pressure, 7 mmHg; diastolic blood pressure, 3 mmHg). IRT is safe and typical program delivery requires only about 17 min weekly. IRT should be used as an adjunct to other exercise modalities, in people unable to complete other types of exercise, or in resistant hypertension.

Isometric exercise training (IET) is increasingly cited for its role in reducing resting blood pressure (BP). Despite this, few studies have investigated a potential sham effect attributing to the success of IET, thus dictating the aim of the present study. Thirty physically inactive males (n = 15) and females (n = 15) were randomly assigned into three groups. The IET group completed a wall squat intervention at 95% peak heart rate (HR) using a prescribed knee joint angle. The sham group performed a parallel intervention, but at an intensity (<75% peak HR) previously identified to be inefficacious over a 4‐week training period. No‐intervention controls maintained their normal daily activities. Pre‐ and post‐measures were taken for resting and continuous blood pressure and cardiac autonomic modulation. Resting clinic and continuous beat‐to‐beat systolic (−15.2 ± 9.2 and −7.3 ± 5.6 mmHg), diastolic (−4.6 ± 5 and −4.5 ± 5.1), and mean (−7 ± 4.2 and −7.5 ± 5.3) BP, respectively, all significantly decreased in the IET group compared to sham and no‐intervention control. The IET group observed a significant decrease in low‐frequency normalized units of heart rate variability concurrent with a significant increase in high‐frequency normalized units of heart rate variability compared to both the sham and no‐intervention control groups. The findings of the present study reject a nonspecific effect and further support the role of IET as an effective antihypertensive intervention.

Hypertension is a major risk factor for cardiovascular disease. Isometric exercise training (IET) reduces resting and ambulatory blood pressure; however, few studies have investigated the myocardial adaptations following IET. We randomly assigned 24 unmedicated hypertensive patients in a cross-over study design to 4-weeks of IET and control period, separated by a 3-week washout period. Speckle tracking echocardiography was used to measure left ventricular (LV) mechanics, and global myocardial work indices were derived from non-invasive LV pressure-strain loops constructed from global longitudinal strain (GLS) indexed to brachial systolic blood pressure. IET significantly improved GLS (− 2.3 ± 2%, p < 0.001) and global work efficiency (2.8 ± 2%, p < 0.001), and significantly reduced global wasted work (− 42.5 ± 30 mmHg%, p < 0.001) with no significant change during the control period. This is the first evidence to demonstrate that IET significantly improved cardiac health in a relevant patient population. Our findings have important clinical implications for patients with high blood pressure and support the role of IET as a safe and viable therapeutic and preventative intervention in the treatment of hypertension.

Global longitudinal strain (GLS) is becoming routinely used to direct the medical management of various cardiac diseases, but its application in pregnancy is unclear. Our objective was to perform a meta-analysis and pool multiple study data to consolidate the evidence base for the role of GLS in the assessment of women with hypertensive disorders of pregnancy (HDP). Electronic database searches were performed in PubMed/Medline and EMBASE for research articles reporting GLS in pregnancies complicated by HDP and normotensive pregnancies that have been published up to September 2021. The meta-analysis included 17 studies with a pooled sample size of 1723 participants, which included 951 women with HDP, of which 680 were preeclamptic, and 772 controls. The primary random-effects pooled analysis demonstrated a statistically significant weighted mean difference in GLS between the HDP and control group (mean difference: 3.08% [CI, 2.33-3.82], P<0.001). When analyzed including only preeclamptic studies, there was also a statistically significant mean difference (mean difference: 2.98% [95% CI, 1.97-3.99], P<0.001). This meta-analysis demonstrates that HDP is associated with greater cardiac maladaptation, evidenced by a significantly reduced GLS compared with normal pregnancy. Echocardiography should be considered as a screening tool in women with HDP to enable early cardiovascular risk prevention through national initiatives.

The validity of ratings of perceived exertion (RPE) during aerobic training is well established; however, its validity during resistance exercise is less clear. This meta-analysis used the known relationships between RPE and exercise intensity (EI), heart rate (HR), blood lactate (BLa), blood pressure (BP) and electromyography (EMG) to determine the convergent validity of RPE as a measure of resistance exercise intensity and physiological exertion, during different forms of resistance exercise. Additionally, this study aims to assess the effect of several moderator variables on the strength of the validity coefficients, so that clearer guidance can be given on the use of RPE during resistance exercise. An online search of 4 databases and websites (PubMed, Web of Science SPORTDiscus and ResearchGate) was conducted up to 28 February 2020. Additionally, the reference lists of the included articles were inspected manually for further unidentified studies. The inclusion criteria were healthy participants of any age, a rating scale used to measure RPE, resistance exercise of any type, one cohort receiving no other intervention, and must present data from one of the following outcome measures: EI, HR, BP, EMG or BLa. Weighted mean effect sizes (r) were calculated using a random-effects model. Heterogeneity was assessed using the τ2 and I2 statistics. Moderator analysis was conducted using random-effects meta-regression. One-hundred and eighteen studies were included in the qualitative synthesis, with 75 studies (99 unique cohorts) included in the meta-analysis. The overall weighted mean validity coefficient was large (0.88; 95% CI 0.84–0.91) and between studies heterogeneity was very large (τ2 = 0.526, I2 = 96.1%). Studies using greater workload ranges, isometric muscle actions, and those that manipulated workload or repetition time, showed the highest validity coefficients. Conversely, sex, age, training status, RPE scale used, and outcome measure no significant effect. RPE provides a valid measure of exercise intensity and physiological exertion during resistance exercise, with effect sizes comparable to or greater than those shown during aerobic exercise. Therefore, RPE may provide an easily accessible means of prescribing and monitoring resistance exercise training. Trial Registration The systematic review protocol was registered on the PROSPERO database (CRD42018102640).

As the leading cause of cardiovascular disease and mortality, hypertension remains a global health problem. Isometric exercise training (IET) has been established as efficacious in reducing resting blood pressure (BP); however, no research to date has investigated its effects on the myocardial performance index (MPI). Twenty-four unmedicated hypertensive patients were randomized to 4 weeks of IET and a control period in a crossover design. Tissue Doppler imaging was used to acquire cardiac time intervals pre- and post-IET and during the control periods. IET significantly improved all measures of cardiac time intervals, including isovolumic relaxation time (83.1 ± 10.3 vs. 76.1 ± 11.2 ms, p = 0.006), isovolumic contraction time (84.8 ± 10.3 vs. 72.8 ± 6.4 ms, p < 0.001), ejection time (304.6 ± 30.2 vs. 321.4 ± 20.8 ms, p = 0.015) and the MPI (0.56 ± 0.09 vs. 0.47 ± 0.05, p < 0.001). This is the first study to demonstrate that IET significantly improves cardiac time intervals. These findings may have important clinical implications, highlighting the potential utility of IET in the management of cardiac health in hypertensive patients.

Objective: Isometric exercise training (IET) over 4-12 weeks is an effective antihypertensive intervention. However, blood pressure (BP) reductions are reversible if exercise is not maintained. No work to date has investigated the long-term effects of IET on resting BP. Methods: We randomized 24 unmedicated patients with high-normal BP to a 1-year wall squat IET intervention or nonintervention control group. Resting BP and various clinically important haemodynamic variables, including heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) were measured pre and post the 1-year study period. Results: One year of IET produced statistically significant reductions in resting systolic (-8.5 +/- 5 mmHg, P < 0.001) and diastolic (-7.3 +/- 5.8 mmHg, P < 0.001) BP compared with the control group. There was also a significant reduction in resting HR (-4.2 +/- 3.7 b/min, P = 0.009) and a significant increase in SV (11.2 +/- 2.8 ml, P = 0.012), with no significant change in CO (0.12 +/- 2.8 l/min, P = 0.7). TPR significantly decreased following IET (-246 +/- 88 dyne center dot s/cm(5), P = 0.011). Adherence to the IET sessions was 77% across all participants (3x IET sessions per week), with no participant withdrawals. Conclusion: This novel study supports IET as an effective long-term strategy for the management of resting BP, producing clinically important, chronic BP adaptations in patients at risk of hypertension. Importantly, this work also demonstrates impressive long-term adherence rates, further supporting the implementation of IET as a means of effective BP management in clinical populations.

Acute cardiovascular responses following a single session of isometric exercise (IE) have been shown to predict chronic adaptations in blood pressure (BP) regulation. It was hypothesised that exercises which recruit more muscle mass induce greater reductions in BP compared to exercises using smaller muscle mass. To test this hypothesis, the current study aimed to compare the acute haemodynamic and autonomic responses to a single session of isometric wall squat (IWS) and isometric handgrip (IHG) training. Twenty-six sedentary participants performed a single IWS and IHG session in a randomised cross-over design, with training composed of 4 × 2-min contractions, with 2-min rest, at 95 HRpeak and 30% MVC respectively. Haemodynamic and cardiac autonomic variables were recorded pre, during, immediately post, and 1-h post-exercise, with the change from baseline for each variable used for comparative analysis. During IWS exercise, there was a significantly greater increase in systolic BP (P < 0.001), diastolic BP (P < 0.001), mean BP (P < 0.001), heart rate (P < 0.001), and cardiac output (P < 0.001), and a contrasting decrease in baroreflex effectiveness index (BEI) and cardiac baroreceptor sensitivity (cBRS). In the 10-min recovery period following IWS exercise, there was a significantly greater reduction in systolic BP (P = 0.005), diastolic BP (P = 0.006), mean BP (P = 0.003), total peripheral resistance (TPR) (P < 0.001), BEI (P = 0.003), and power spectral density (PSD-RRI) (P < 0.001). There were no differences in any variables between conditions 1-h post exercise. Isometric wall squat exercise involving larger muscle mass is associated with a significantly greater post-exercise hypotensive response during a 10-min recovery window compared to smaller muscle mass IHG exercise. The significantly greater reduction in TPR may be an important mechanism for the differences in BP response.