Double-leg isometric exercise training in older men

Effects of a maintenance period on ambulatory blood pressure and morning blood pressure surge in young normotensives post isometric training

Isometric resistance training (IRT) has emerged as an efficacious therapeutic intervention to reduce ambulatory blood pressure (BP), and BP diurnal variability. However, once the required decreases in BP have been achieved the efficacy of implementing a reduced maintenance dose is not understood. Therefore, the purpose of this study was to determine the effects of an 8-week maintenance period (8-week) following the cessation of the prescribed 8-week IRT in young normotensives. Twenty-two recreationally active, not resistance trained, normotensive (24-h ambulatory SBP, ≥130 mmHg) young adults were randomly assigned to a training-maintenance [TG-MT; n = 13 (female = 5); age 21 ± 2 years] or a non-training control [CON; n = 9 (female = 4); age 23 ± 3 years] group. Ambulatory BP, morning BP surge (MBPS) and average real variability (ARV) were measured prior to, after 8 weeks of bilateral leg IRT (4x2-minute contractions at 20% MVC with 2-min rest periods, 3 days/week) and following an 8-week (once per week) maintenance period. On completion of the maintenance period the significant reductions seen following the IRT were maintained within the TG-MT group in 24-h ambulatory SBP (6 ± 4 mmHg, p < 0.001), daytime (5 ± 5 mmHg, p = 0.002), MBPS (7 ± 10 mmHg, p = 0.019) and 24-h SBP ARV (2.03 ± 1.44 mmHg, p = 0.001), daytime SBP ARV (2.04 ± 1.78 mmHg, p = 0.003). These results show that reductions in ambulatory BP (24-h SBP and daytime SBP), in addition to BP diurnal variations (MBPS, 24-h SBP ARV and daytime SBP AVR) are maintained following an 8-week maintenance dose in young adults and add further weight to the growing body of evidence promoting IRT as an efficacious therapeutic exercise intervention to prevent or reduce BP.

Isometric Exercise Training and Arterial Hypertension: An Updated Review

Hypertension is recognised as a leading attributable risk factor for cardiovascular disease and premature mortality. Global initiatives towards the prevention and treatment of arterial hypertension are centred around non-pharmacological lifestyle modification. Exercise recommendations differ between professional and scientific organisations, but are generally unanimous on the primary role of traditional aerobic and dynamic resistance exercise. In recent years, isometric exercise training (IET) has emerged as an effective novel exercise intervention with consistent evidence of reductions in blood pressure (BP) superior to that reported from traditional guideline-recommended exercise modes. Despite a wealth of emerging new data and endorsement by select governing bodies, IET remains underutilised and is not widely prescribed in clinical practice. This expert-informed review critically examines the role of IET as a potential adjuvant tool in the future clinical management of BP. We explore the efficacy, prescription protocols, evidence quality and certainty, acute cardiovascular stimulus, and physiological mechanisms underpinning its anti-hypertensive effects. We end the review with take-home suggestions regarding the direction of future IET research.

The implementation of a home-based isometric wall squat intervention using ratings of perceived exertion to select and control exercise intensity: a pilot study in normotensive and pre-hypertensive adults

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.

An evidence-based guide to the efficacy and safety of isometric resistance training in hypertension and clinical implications

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.

Acute Blood Pressure Response to Different Types of Isometric Exercise: A Systematic Review with Meta-Analysis

Background

This study aimed to identify the blood pressure (BP) responses during different types of isometric exercises (IE) in adults and to evaluate whether BP responses according to IE is influenced by the characteristics of participants and exercise protocols.

Methods

The search was conducted in PubMed, Cochrane Central, SPORTDiscus, and LILACS databases in June 2020. Random effects models with a 95% confidence interval and p < 0.05 were used in the analyses.

Results

Initially, 3201 articles were found and, finally, 102 studies were included in this systematic review, seven of which were included in the meta-analysis comparing handgrip to other IE. Two-knee extension and deadlift promoted greater increases in systolic (+9.8 mmHg; p = 0.017; I 2 = 74.5% and +26.8 mmHg; p ≤ 0.001; I 2 = 0%, respectively) and diastolic (+7.9 mmHg; p = 0.022; I 2 = 68.6% and +12.4 mmHg; p ≤ 0.001; I 2 = 36.3%, respectively) BP compared to handgrip. Men, middle-aged/elderly adults, hypertensive individuals, and protocols with higher intensities potentiate the BP responses to handgrip exercise (p ≤ 0.001).

Conclusions

IE involving larger muscle groups elicit greater BP responses than those involving smaller muscle masses, especially in men, middle-aged/elderly adults and hypertensive individuals. Future studies should directly compare BP responses during various types of IE in different populations.

Mechanisms for blood pressure reduction following isometric exercise training: a systematic review and meta-analysis

OBJECTIVE

Isometric exercise training (IET) is established as an effective antihypertensive intervention. Despite this, the physiological mechanisms driving blood pressure (BP) reductions following IET are not well understood. Therefore, we aimed to perform the first meta-analysis of the mechanistic changes measured following IET.

METHODS

PubMed, Cochrane library and SPORTDiscus were systematically searched for randomized controlled trials published between January 2000 and December 2021 reporting the effects of IET on resting BP and at least one secondary mechanistic parameter following a short-term intervention (2-12 weeks).

RESULTS

Eighteen studies with a pooled sample size of 628 participants were included in the final analysis. IET produced significant reductions in resting systolic and diastolic BP of 9.35 mmHg (95% confidence interval [CI] = -7.80 to -10.89, P  < 0.001) and 4.30 mmHg (CI = -3.01 to -5.60, P  < 0.001), respectively. Mechanistically, IET produced a statistically significant reduction in resting heart rate (mean difference [MD]: -1.55 bpm, CI = -0.14 to -2.96, P  = 0.031) and a significant increase in stroke volume (MD: 6.35 ml, CI = 0.35 to 12.60, P  = 0.038), with no significant change in cardiac output. Conversely, total peripheral resistance (TPR) significantly decreased following IET (MD: -100.38 dyne s -1 cm 5 , CI = -14.16 to -186.61, P  = 0.023), with significant improvements in the low frequency to high frequency heart rate variability ratio (MD: -0.41, CI = -0.09 to -0.73, P  = 0.013) and baroreceptor reflex sensitivity (MD: 7.43 ms/mmHg, P  < 0.001).

CONCLUSION

This work demonstrates that a reduction in TPR, potentially mediated through enhanced autonomic vasomotor control, is primarily responsible for BP reductions following IET. Furthermore, this novel analysis suggests wall squat interventions to be the most effective IET mode, with clinically relevant differences in BP reductions compared to handgrip and leg extension IET; although future direct comparative research is required.

Effects of isometric resistance training and detraining on ambulatory blood pressure and morning blood pressure surge in young normotensives

Isometric resistance training (IRT) has been shown to reduce resting and ambulatory blood pressure (BP), as well as BP variability and morning BP surge (MBPS). However, there are no data available regarding how long after cessation of IRT these effects are maintained. Therefore, the purpose of this study was to determine the effects of 8 weeks of detraining on resting BP, ambulatory BP and MBPS following 8 weeks of IRT in a population of young normotensive individuals and to further substantiate previously reported reductions in MBPS following IRT. Twenty-five apparently healthy participants with resting BP within the normal range (16 men, age = 23 ± 6 years; 9 women, age = 22 ± 4 years, resting BP: 123 ± 5/69 ± 7 mmHg) were randomly assigned to a training-detraining (TRA-DT, n = 13) or control (CON, n = 12) group. Resting BP, ambulatory BP and MBPS were measured prior to, after 8 weeks of bilateral leg IRT using an isokinetic dynamometer (4 × 2-min contractions at 20% MVC with 2-min rest periods, 3 days/week) and following an 8-week detraining period. There were significant reductions in 24-h ambulatory systolic BP (SBP) and calculated SBP average real variability (ARV) following IRT that were maintained after detraining (pre-to-post detraining, −6 ± 4 mmHg, p = 0.008, −2 ± 1.5 mmHg, p = 0.001). Similarly, the training-induced decreases in daytime SBP and daytime SBP ARV (pre-to-post detraining, −5 ± 6 mmHg, p = 0.001; −2 ± 1.2 mmHg, p = 0.001, respectively), MBPS (pre-to-post detraining, −6 ± 9 mmHg, p = 0.046) and resting SBP (pre-to-post detraining, −4 ± 6 mmHg, p = 0.044) were preserved. There were no changes in night-time or night-time SBP ARV across all time points (pre-to-post detraining, −1 ± 8 mmHg, p = 1.00, −0.7 ± 2.9 mmHg, p = 1.00). These results confirm that IRT causes significant reductions in resting BP, ambulatory BP, ambulatory ARV and MBPS. Importantly, the changes remained significantly lower than baseline for 8 weeks after cessation of training, suggesting a sustained effect of IRT.

The Comparative Effect of Different Timings of Whole Body Cryotherapy Treatment With Cold Water Immersion for Post-Exercise Recovery

Despite several established benefits of Whole Body Cryotherapy (WBC) for post-exercise recovery, there is a scarcity of research which has identified the optimum WBC protocol for this purpose. This study investigated the influence of WBC treatment timing on physiological and functional responses following a downhill running bout. An additional purpose was to compare such responses with those following cold water immersion (CWI), since there is no clear consensus as to which cold modality is more effective for supporting athletic recovery. Thirty-three male participants (mean ± SD age 37.0 ± 13.3 years, height 1.76 ± 0.07 m, body mass 79.5 ± 13.7 kg) completed a 30 min downhill run (15% gradient) at 60% VO₂ max and were then allocated into one of four recovery groups: WBC1 (n = 9) and WBC4 (n = 8) underwent cryotherapy (3 min, −120°C) 1 and 4 h post-run, respectively; CWI (n = 8) participants were immersed in cold water (10 min, 15°C) up to the waist 1 h post-run and control (CON, n = 8) participants passively recovered in a controlled environment (20°C). Maximal isometric leg muscle torque was assessed pre and 24 h post-run. Blood creatine kinase (CK), muscle soreness, femoral artery blood flow, plasma IL-6 and sleep were also assessed pre and post-treatment. There were significant decreases in muscle torque for WBC4 (10.9%, p = 0.04) and CON (11.3% p = 0.00) and no significant decreases for WBC1 (5.6%, p = 0.06) and CWI (5.1%, p = 0.15). There were no significant differences between groups in muscle soreness, CK, IL-6 or sleep. Femoral artery blood flow significantly decreased in CWI (p = 0.02), but did not differ in other groups. WBC treatments within an hour may be preferable for muscle strength recovery compared to delayed treatments; however WBC appears to be no more effective than CWI. Neither cold intervention had an impact on inflammation or sleep.

The Effect of Repetitive Whole Body Cryotherapy Treatment on Adaptations to a Strength and Endurance Training Programme in Physically Active Males

Despite its potential merit in sport and exercise recovery, the implications of repetitive Whole Body Cryotherapy (WBC) during training programmes require further review due to the possibility of repetitive cold interfering with long term adaptations. This study investigated the impact of two weekly 3 min WBC sessions (30 s at −60°C, 150 s at −120°C) on adaptations to a 6 week strength and endurance training programme. Sixteen male participants (mean ± SD age 33.4 ± 9.8 years, body mass 82.3 ± 9.8 kg) randomly allocated into WBC (n = 7) and non-cryotherapy control (CON, n=9) groups completed the programme consisting of two weekly strength and plyometric training sessions and two weekly 30 min runs (70% VO₂ max). Participants were assessed for body fat, VO₂ max, muscle torque, three repetition maximum barbell squat and countermovement jump height before and after the programme. Resistance and running intensities were progressed after 3 weeks. Participants in both groups significantly improved muscle torque (WBC: 277.1 ± 63.2 Nm vs. 318.1 ± 83.4 Nm, p < 0.01, d = 0.56; CON: 244.6 ± 50.6 Nm vs. 268.0 ± 71.8 Nm, p = 0.05, d = 0.38) and barbell squat (WBC: 86.4 ± 19.5 kg vs. 98.9 ± 15.2 kg, p = 0.03, d = 0.69; CON: 91.1 ± 28.7 kg vs. 106.1 ± 30.0 kg, p < 0.01, d=0.51) following the 6 week programme. For the CON group, there was also a significant reduction in body fat percentage (p = 0.01) and significant increase in jump height (p = 0.01). There was no significant increase in VO₂ max for either group (both p > 0.2). There was no difference between WBC and CON for responses in muscle torque, 3RM barbell squat and body fat, however WBC participants did not increase their jump height (p = 0.23). Repetitive WBC does not appear to blunt adaptations to a concurrent training programme, although there may be an interference effect in the development of explosive power. Sports practitioners can cautiously apply repetitive WBC to support recovery post-exercise without undue concern on athletes' fitness gains or long term performance, particularly throughout training phases focused more on general strength development than explosive power.

Isometric Exercise Training: A Review of Hypothesized Mechanisms and Protocol Application in Persons with Hypertension

According to the American Heart Association 116.4 million, or 46% of US adults are estimated to have hypertension. Although, traditional moderate intensity aerobic exercise training is associated with reducing blood pressure by 5-8 mmHg, barriers to this modality of exercise training exist. Thus, the purpose of this review is to evaluate the mechanisms and incorporation of isometric exercise training (IET) as an adjunctive mode of exercise in a population with HTN. Based upon the articles reviewed from the years 2000-2020 which incorporated IET and provided clear protocols lasting 4 or more weeks, meaningful reductions in blood pressure occurred following IET (SBP, -9.7 ± 3.3 mmHg; DBP, -4.8 ± 2.6 mmHg) which support the need to increase adoption of this exercise form into practice to help treat hypertension. Specifically, an IET program of 12-20 minutes per day, 3 times per week, could improve blood pressure reduction in those with hypertension. IET has the potential to produce significant and clinically meaningful blood pressure reductions and could serve as an adjunctive exercise modality alongside the established exercise prescription for those with hypertension.

The effectiveness and safety of isometric resistance training for adults with high blood pressure: a systematic review and meta-analysis

High blood pressure (BP) is a global health challenge. Isometric resistance training (IRT) has demonstrated antihypertensive effects, but safety data are not available, thereby limiting its recommendation for clinical use. We conducted a systematic review of randomized controlled trials comparing IRT to controls in adults with elevated BP (systolic ≥130 mmHg/diastolic ≥85 mmHg). This review provides an update to office BP estimations and is the first to investigate 24-h ambulatory BP, central BP, and safety. Data were analyzed using a random-effects meta-analysis. We assessed the risk of bias with the Cochrane risk of bias tool and the quality of evidence with GRADE. Twenty-four trials were included (n = 1143; age = 56 ± 9 years, 56% female). IRT resulted in clinically meaningful reductions in office systolic (-6.97 mmHg, 95% CI -8.77 to -5.18, p < 0.0001) and office diastolic BP (-3.86 mmHg, 95% CI -5.31 to -2.41, p < 0.0001). Novel findings included reductions in central systolic (-7.48 mmHg, 95% CI -14.89 to -0.07, p = 0.035), central diastolic (-3.75 mmHg, 95% CI -6.38 to -1.12, p = 0.005), and 24-h diastolic (-2.39 mmHg, 95% CI -4.28 to -0.40, p = 0.02) but not 24-h systolic BP (-2.77 mmHg, 95% CI -6.80 to 1.25, p = 0.18). These results are very low/low certainty with high heterogeneity. There was no significant increase in the risk of IRT, risk ratio (1.12, 95% CI 0.47 to 2.68, p = 0.8), or the risk difference (1.02, 95% CI 1.00 to 1.03, p = 0.13). This means that there is one adverse event per 38,444 bouts of IRT. IRT appears safe and may cause clinically relevant reductions in BP (office, central BP, and 24-h diastolic). High-quality trials are required to improve confidence in these findings. PROSPERO (CRD42020201888); OSF ( https://doi.org/10.17605/OSF.IO/H58BZ ).

Isometric exercise and inter-individual response differences on resting systolic and diastolic blood pressure in adults: a meta-analysis of randomized controlled trials

PURPOSE

Isometric exercise (IE) has been shown to reduce resting systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults. However, no one to date has determined whether true inter-individual response differences (IIRD) versus random variability exist with respect to IE and resting SBP and DBP in adults ≥18 years of age. The purpose of the current study was to address this gap.

METHODS AND MATERIALS

Using the meta-analytic approach, randomised controlled trials from a recent meta-analysis that examined the effects of IE on resting SBP and DBP were included. Change outcome standard deviations for SBP and DBP from IE and control groups were used to calculate true IIRD from each study. The inverse variance heterogeneity (IVhet) model was used to pool results.

RESULTS

Pooled changes for true IIRD in SBP (16 studies, 411 participants) were 3.3 mmHg (95% confidence interval, -3.1 to 5.6 mmHg) while tau (τ) was 4.2. For DBP, true IIRD (16 studies, 411 participants) were 2.3 mmHg (95% confidence interval, -0.7 to 3.3 mmHg) while tau (τ) was 2.2. The 95% prediction interval for true IIRD in a future study was -5.8 to 7.4 mmHg for SBP and -2.7 to 4.2 mmHg for DBP. The percent chance, i.e. probability, of a clinically meaningful difference of 2 mmHg was 68% for SBP and 75% for DBP, both of which were only considered as 'possibly clinically important'.

CONCLUSION

While IE reduces resting SBP and DBP in adults, the results of the current study suggest that random variability versus true IIRD account for any potential differences as a result of IE on changes in resting SBP and DBP in adults. Thus, a search for potential moderators and mediators, including potential genetic interactions associated with IE, may not be warranted.

Validity and reliability of RPE as a measure of intensity during isometric wall squat exercise

BACKGROUND AND AIMS

Isometric exercise (IE), including wall squat training, has been shown to be effective at reducing resting blood pressure (BP). Rating of perceived exertion (RPE) is also widely used as an accessible additional measure of IE intensity. Despite this, no RPE scales have been specifically designed for use with IE and it is not clear whether RPE is sensitive enough to distinguish between different lower limb IE workloads. Therefore, the aims of this study were to assess the validity and reliability of RPE as a measure of IE intensity (workload) and physiological exertion (Heart rate and BP), and to examine whether RPE is able to discern differences in wall squat workload (knee angle) at a resolution of 10-degrees, as was previous shown for heart rate (HR) and BP.

METHODS

Twenty-nine male participants completed eight separate isometric wall squat testing sessions, separated by a minimum of 5-h. Each session consisted of a single 2-min isometric wall squat test, at one of five randomized workloads (knee joint angles). Three of the knee angles were repeated, a second time, to allow measurements of reliability. Throughout the exercise protocol, HR and BP were recorded continuously; values for each 30-s time-point were calculated as the mean of the proceeding 5-s, and peak values for the 2-min bout were taken as the mean results for the final 5-s of the bout. In addition, mean results for the full 2-min period were calculated. RPE was collected every 30 s. Concurrent validity was assessed by correlating RPE results with the criterion measures: Knee joint angle, HR, and BP. Differences in RPE were assessed across consecutive workloads and time-points.

RESULTS

There were significant increases in RPE at each consecutive wall squat workload (P<0.001) and between each consecutive 30-s time point (P<0.001). In addition, the RPE results produced a significant inverse relationship with knee angle (r=-0.79; P<0.001) and significant positive relationships with HR (r=0.53, P<0.001) and BP (systolic: r=0.77; diastolic: r=0.62; and mean arterial pressure: r=0.70, P<0.001).

CONCLUSION

RPE provides a valid and reliable measure of isometric wall squat intensity, physiological exertion and can discern between knee angles with a resolution of 10°.

RELEVANCE FOR PATIENTS

Patients and practitioners implementing isometric exercise training for arterial blood pressure reduction can use RPE to accurately monitor the intensity of the exercise and the physiological responses.

The Effects of Age and Body Fat Content on Post-Downhill Run Recovery Following Whole Body Cryotherapy

This study explored the effects of age and body fat content on responses to whole body cryotherapy (WBC) following a downhill running bout. Forty-one male participants (mean ± SD age 42.0 ± 13.7 years, body mass 75.2 ± 10.8 kg) were allocated into WBC (n = 26) and control (CON, n = 15) groups. WBC participants were divided into old (OLD, ≥45 years, n = 10) and young (YNG, <40 years, n = 13), as well as high fat (HFAT, ≥20%, n = 10) and low fat (LFAT ≤ 15%, n = 8) groups. Participants completed a 30 min downhill run (15% gradient) at 60% VO2 max. The WBC group underwent cryotherapy (3 min, -120 °C) 1 h post-run and CON participants passively recovered in a controlled environment (20 °C). Maximal isometric leg muscle torque was assessed pre and 24 h post-run. Blood creatine kinase (CK) and muscle soreness were assessed pre, post, one hour and 24 h post-run. Muscle torque significantly decreased in both groups post-downhill run (WBC: 220.6 ± 61.4 Nm vs. 208.3 ± 67.6 Nm, p = 0.02; CON: 239.7 ± 51.1 Nm vs. 212.1 ± 46.3 Nm, p = 0.00). The mean decrease in WBC was significantly less than in CON (p = 0.04). Soreness and CK increased 24 h post for WBC and CON (p < 0.01) with no difference between groups. Muscle torque significantly decreased in OLD participants (p = 0.04) but not in YNG (p = 0.55). There were no differences between HFAT and LFAT (all p values > 0.05). WBC may attenuate muscle damage and benefit muscle strength recovery following eccentrically biased exercises, particularly for young males.

Validity and reliability of the 'Isometric Exercise Scale' (IES) for measuring ratings of perceived exertion during continuous isometric exercise

Isometric exercise (IE) interventions are an effective non-medical method of reducing arterial blood pressure (BP). Current methods of prescribing and controlling isometric exercise intensity often require the use of expensive equipment and specialist knowledge. However, ratings of perceived exertion (RPE) may provide a more accessible means of monitoring exercise intensity. Therefore, the aim of this study was to assess the validity of a specific Isometric Exercise Scale (IES) during a continuous incremental IE test. Twenty-nine male participants completed four incremental isometric wall squat tests. Each test consisted of five 2-min stages of progressively increasing workload. Workload was determined by knee joint angle from 135° to 95°. The tests were continuous with no rest periods between the stages. Throughout the exercise protocol, RPE (IES and Borg's CR-10), heart rate and blood pressure were recorded. A strong positive linear relationship was found between the IES and the CR-10 (r = 0.967). Likewise, strong positive relationships between the IES and wall squat duration (r = 0.849), HR (r = 0.819) and BP (r = 0.841) were seen. Intra-class correlation coefficients and coefficients of variations for the IES ranged from r = 0.81 to 0.91 and 4.5-54%, respectively, with greater reliability seen at the higher workloads. The IES provides valid and reliable measurements of RPE, exercise intensity, and the changes in physiological measures of exertion during continuous incremental IE; as such, the IES can be used as an accessible measure of exercise intensity during IE interventions.

Blood pressure-lowering efficacy of a 6-week multi-modal isometric exercise intervention

Isometric exercise training (IET) is an effective method for reducing resting blood pressure (BP). To date, no research studies have been conducted using multiple exercises within an IET intervention. Previous research has suggested that varied exercise programmes may have a positive effect on adherence. Therefore, this randomized controlled study aimed to investigate the BP-lowering efficacy of a multi-modal IET (MIET) intervention in healthy young adults. Twenty healthy participants were randomized to an MIET [n = 10; four women; SBP 117.9 ± 6.9 mmHg; DBP 66.3 ± 5.1 mmHg] or control (CON) group (n = 10; five women; SBP, 123.3 ± 10.4 mmHg; DBP, 77.3 ± 6.7 mmHg). The MIET group completed three sessions per week of 4, 2-min isometric contractions, with a 1-min rest between each contraction, for 6 weeks. Resting BP and heart rate (HR) were measured at baseline and post-intervention. Pre-to-post intervention within-group reductions in resting BP were observed (SBP: 5.3 ± 6.1 mmHg, DBP: 3.4 ± 3.7 mmHg, MAP: 4.0 ± 3.9 mmHg, HR: 4.8 ±6 .6 bpm), although clinically relevant (≥2 mmHg), these changes were not statistically significant. Significant (p < 0.05) between-group differences were found between the intervention and control groups, indicating that the MIET intervention has a greater BP-lowering effect compared to control. The clinically relevant post-training reductions in resting BP suggest that MIET may be a promising additional IET method for hypertension prevention. These findings; however, must be interpreted with caution due to the small sample size and the non-clinical cohort.

Is Low-Intensity Isometric Handgrip Exercise an Efficient Alternative in Lifestyle Blood Pressure Management? A Systematic Review

CONTEXT

High blood pressure is one of the leading preventable causes of cardiovascular death worldwide. In this regard, several studies have shown interest in the benefits of isometric exercise on blood pressure regulation.

OBJECTIVE

To assess whether low-intensity isometric handgrip exercise (LI-IHE) is an effective strategy to lower blood pressure levels in prehypertensive and hypertensive patients.

DATA SOURCE

This study was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and registered with PROSPERO. Potentially eligible studies were identified after a systematic search conducted on 4 international databases: PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), PEDro, and SPORTDiscus.

STUDY SELECTION

We included randomized controlled trials that comprised patients who received LI-IHE.

STUDY DESIGN

Systematic review with meta-analysis.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Data related to patient characteristics, exercise programs, risk-of-bias assessment, and outcomes of interest were systematically reviewed independently by 2 authors.

RESULTS

The following reductions (mean differences) were observed after LI-IHE: systolic blood pressure (SBP), (MD) = -5.43 mm Hg; (95% CI, -8.47 to -2.39; P = 0.0005); diastolic blood pressure (DBP), -2.41 mm Hg (95% CI, -4.33 to -0.48; P = 0.01); mean arterial pressure (MAP), -1.28 mm Hg (95% CI, -2.99 to 0.44; P = 0.14).

CONCLUSION

LI-IHE seems to lower SBP, DBP, and MAP values in prehypertensive and hypertensive adults. It appears that LI-IHE reduces, in greater magnitude, blood pressure levels in hypertensive patients, specifically in patients aged <45 years, those who are overweight, and those on medications. Nevertheless, substantial heterogeneity in the main results and in the analyses by subgroups generated uncertainty about the real reduction magnitude that LI-IHE can produce on blood pressure.

Effects of isometric resistance training on resting blood pressure: individual participant data meta-analysis

Background:

Previous meta-analyses based on aggregate group-level data report antihypertensive effects of isometric resistance training (IRT). However, individual participant data meta-analyses provide more robust effect size estimates and permit examination of demographic and clinical variables on IRT effectiveness.

Methods:

We conducted a systematic search and individual participant data (IPD) analysis, using both a one-step and two-step approach, of controlled trials investigating at least 3 weeks of IRT on resting systolic, diastolic and mean arterial blood pressure.

Results:

Anonymized individual participant data were provided from 12 studies (14 intervention group comparisons) involving 326 participants (52.7% medicated for hypertension); 191 assigned to IRT and 135 controls, 25.2% of participants had diagnosed coronary artery disease. IRT intensity varied (8–30% MVC) and training duration ranged from 3 to 12 weeks. The IPD (one-step) meta-analysis showed a significant treatment effect for the exercise group participants experiencing a reduction in resting SBP of −6.22 mmHg (95% CI −7.75 to −4.68; P < 0.00001); DBP of −2.78 mmHg (95% CI −3.92 to −1.65; P = 0.002); and mean arterial blood pressure (MAP) of −4.12 mmHg (95% CI −5.39 to −2.85; P < 0.00001). The two-step approach yielded similar results for change in SBP −7.35 mmHg (−8.95 to −5.75; P < 0.00001), DBP MD −3.29 mmHg (95% CI −5.12 to −1.46; P = 0.0004) and MAP MD −4.63 mmHg (95% CI −6.18 to −3.09: P < 0.00001). Sub-analysis revealed that neither clinical, medication, nor demographic participant characteristics, or exercise program features, modified the IRT treatment effect.

Conclusion:

This individual patient analysis confirms a clinically meaningful and statistically significant effect of IRT on resting SBP, DBP and mean arterial blood pressure.

Home-based isometric handgrip training on RBP in hypertensive adults-Partial preliminary findings from RCT

OBJECTIVE

The aim of this study is to confirm whether 8 weeks of home-based isometric handgrip (IHG) training would reduce resting blood pressure (RBP) in an adult Indian population.

METHODOLOGY

Hypertensive patients (Stage 1 [previously prehypertension] and Stage 2 [previously Stage 1 hypertension]) aged 30-45 years, male and female, were included.

INTERVENTION

Two groups were included (active control group and IHG training group at 30% of maximal voluntary isometric contraction). Outcomes of this study were resting pulse rate (PR) and RBP, which were taken at baseline and after 8 weeks. Stratified randomization was done by sex and hypertension grade. The study was a double-blind intervention (both participants and the assessor were blinded to intervention allotment).

RESULTS

Forty hypertensive individuals were randomly assigned to a control (N = 20) and an 8-week home-based IHG training (N = 20) using a stratified random sampling technique. Each training session consisted of 4 × 2 min bouts with a 4-min rest between bouts for 8 weeks. Resting PR and RBP were taken at baseline and after 8 weeks. After 8 weeks, there was a significant reduction in blood pressure and PR values in the IHG group as compared with those in the control group: systolic blood pressure (mean difference, MD -8.75 mmHg; 95% CI [-6.51, -10.39]); diastolic blood pressure (MD -8.35 mmHg; 95% CI [-6.25, -10.45]); mean arterial pressure (MD -8.13 mmHg; 95% CI [-6.21, -10.05]); and PR (MD -8.90 mmHg; 95% CI [-5.08, -12.72].

CONCLUSION

On the basis of study findings, home-based IHG training can be used as an adjunct to control BP in the initial stage of hypertension in an Indian population.

Blood pressure lowering effects of a novel isometric exercise device following a 4-week isometric handgrip intervention

Background: Hypertension is the leading risk factor for global mortality. Isometric resistance exercise training reduces blood pressure (BP). However, the protocols used are often limited by cost/immobility and the use of rigid exercise modalities. In response, a novel more versatile, isometric exercise (IE) device, the IsoBall (IB) was created. Purpose: The aim of this study was to test the BP-lowering effectiveness of this prototype. Methods: Twenty-three healthy participants (29.10±2.19 years old, 173.95±3.83 cm, 75.43±5.06 kg, SBP 127.10±10.37 mmHg, DBP 70.40±6.77 mmHg) were randomly allocated to either a control group (CON) or 2 isometric handgrip (IHG) training groups that used the Zona plus (ZON) and IB devices. The intervention groups completed 3 sessions each week of 4, 2 min IHG at 30% maximal voluntary contraction, with a 1-min rest, for 4 weeks. Resting BP, heart rate (HR) and IHG strength were measured in all groups at baseline and postintervention. Results: Postintervention systolic BP (SBP) was significantly lower in both ZON (114.5±8.2 mmHg, p = 0.000) and IB (119.9±7.0 mmHg, p = 0.000) compared to control (131.0±12.4 mmHg). Postintervention diastolic BP (DBP) was reduced in both intervention groups (ZON 66.6±7.4 mmHg, p = 0.004; IB 65.7±10.0 mmHg, p = 0.012) compared to CON (71.1±8.8 mmHg). Mean arterial pressure (MAP) was reduced in both groups (ZON 82.6±6.8 mmHg, p = 0.000; IB 84.3±9.1 mmHg, p = 0.000) compared to control (91.0±9.7 mmHg). No significant changes were seen in HR or strength (p > 0.05). Conclusion: The results of this study indicate that both the ZON and IB devices elicit significant SBP, DBP and MAP reductions. Despite the ZON group having larger reductions in BP, no significant differences were found between the two devices. Thus, this study indicates the IB device to be an effective alternative to the ZON that can also be used to perform other IE modalities.

Effects of Exercise on the Resting Heart Rate: A Systematic Review and Meta-Analysis of Interventional Studies

Resting heart rate (RHR) is positively related with mortality. Regular exercise causes a reduction in RHR. The aim of the systematic review was to assess whether regular exercise or sports have an impact on the RHR in healthy subjects by taking different types of sports into account. A systematic literature research was conducted in six databases for the identification of controlled trials dealing with the effects of exercise or sports on the RHR in healthy subjects was performed. The studies were summarized by meta-analyses. The literature search analyzed 191 studies presenting 215 samples fitting the eligibility criteria. 121 trials examined the effects of endurance training, 43 strength training, 15 combined endurance and strength training, 5 additional school sport programs. 21 yoga, 5 tai chi, 3 qigong, and 2 unspecified types of sports. All types of sports decreased the RHR. However, only endurance training and yoga significantly decreased the RHR in both sexes. The exercise-induced decreases of RHR were positively related with the pre-interventional RHR and negatively with the average age of the participants. From this, we can conclude that exercise-especially endurance training and yoga-decreases RHR. This effect may contribute to a reduction in all-cause mortality due to regular exercise or sports.

Isometric exercise training for blood pressure management: a systematic review and meta-analysis to optimize benefit

The objective of our study was to examine the effects of isometric resistance training (IRT) on resting blood pressure in adults. We conducted a systematic review and meta-analysis of randomized-controlled trials lasting ⩾2 weeks, investigating the effects of isometric exercise on blood pressure in healthy adults (aged ⩾18 years), published in a peer-reviewed journal between 1 January 1966 to 31 January 2015. We included 11 randomized trials, totaling 302 participants. The following reductions were observed after isometric exercise training; systolic blood pressure (SBP) mean difference (MD) -5.20 mm Hg (95% confidence interval (CI) -6.08 to -4.33, P<0.00001); diastolic blood pressure (DBP) MD -3.91 mm Hg (95% CI -5.68 to -2.14, P<0.0001); and mean arterial blood pressure (MAP) MD -3.33 mm Hg (95% CI -4.01 to -2.66, P<0.00001). Sub-analyses showed males tended to reduce MAP MD -4.13 mm Hg (95% CI -5.08 to -3.18) more than females. Subjects aged ⩾45 years demonstrated larger reductions in MAP MD -5.51 mm Hg (95% CI -6.95 to -4.06) than those <45 years. Subjects undertaking ⩾8 weeks of IRT demonstrated a larger reduction in SBP MD -7.26 mm Hg (95% CI -8.47 to -6.04) and MAP MD -4.22 mm Hg (95% CI -5.08 to -3.37) than those undertaking<8 weeks. Hypertensive participants in IRT demonstrated a larger reduction in MAP MD -5.91 mm Hg (95% CI -7.94 to -3.87) than normotensive participants MD -3.01 mm Hg (95% CI -3.73 to -2.29). Our study indicated that IRT lowers SBP, DBP and MAP. The magnitude of effect may be larger in hypertensive males aged ⩾45 years, using unilateral arm IRT for >8 weeks.

Isometric exercise training for blood pressure management: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis quantifying the effects of isometric resistance training on the change in systolic blood pressure(SBP), diastolic blood pressure (DBP), and mean arterial pressure in subclinical populations and to examine whether the magnitude of change in SBP and DBP was different with respect to blood pressure classification.

PATIENTS AND METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials lasting 4 or more weeks that investigated the effects of isometric exercise on blood pressure in healthy adults (aged ≥18 years) and were published in a peer-reviewed journal. PubMed, CINAHL, and the Cochrane Central Register of Controlled Trials were searched for trials reported between January 1, 1966, and July 31, 2013. We included 9 randomized trials, 6 of which studied normotensive participants and 3 that studied hypertensive patients, that included a total of 223 participants (127 who underwent exercise training and 96 controls).

RESULTS

The following reductions were observed after isometric exercise training: SBP-mean difference (MD), -6.77 mm Hg (95% CI, -7.93 to -5.62 mm Hg; P<.001); DBP-MD, -3.96 mm Hg (95% CI, -4.80 to -3.12 mm Hg; P<.001); and mean arterial pressure-MD, -3.94 mm Hg (95% CI, -4.73 to -3.16 mm Hg; P<.001). A slight reduction in resting heart rate was also observed (MD, -0.79 beats/min; 95% CI, -1.23 to -0.36 beats/min; P=.003).

CONCLUSION

Isometric resistance training lowers SBP, DBP, and mean arterial pressure. The magnitude of effect is larger than that previously reported in dynamic aerobic or resistance training. Our data suggest that this form of training has the potential to produce significant and clinically meaningful blood pressure reductions and could serve as an adjunctive exercise modality.