Acute blood pressure responses after different isometric handgrip protocols in hypertensive patients

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.

Isometric handgrip training, but not a single session, reduces blood pressure in individuals with hypertension: a systematic review and meta-analysis

Aerobic exercise is a leading strategy for the prevention/management of systemic arterial hypertension, but other modalities of exercise have also been explored. Thus, we examined the acute effect of isometric handgrip exercise (IHGE) and the chronic effect of isometric handgrip training (IHGT) on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in individuals with hypertension without comorbid conditions. We conducted a systematic review with meta-analysis of randomized controlled trials (RCTs) involving adults with hypertension. We searched the electronic databases MEDLINE (PubMed), Cochrane, Web of Science, LILACS, EMBASE and PEDro. We used random-effects model for the analyses, RoB2 tool to assess the risk of bias, and GRADE to assess the strength of evidence. A total of 9 RCTs (2 for IHGE and 7 for IHGT) were selected. Compared to a control condition, IHGE did not have any effect on SBP/DBP. Unlike, the pooled mean effect of IHGT showed SBP was reduced by 6.7 mmHg (95% CI -10.3 to -3.4 mmHg) and DBP by 4.5 mmHg (95% CI -7.3 to -1.7 mmHg) in individuals with hypertension. Also, the 95% prediction interval (95% PI) of IGHT was -10.9 to -2.5 mmHg for SBP and -10.2 to +1.2 mmHg for DBP. In conclusion, while IHGE did not produce post-exercise hypotension in the population studied, IHGT reduced SBP/DBP in individuals with hypertension with clinically important reductions in SBP (-6.7 mmHg) and DBP (-4.5 mmHg). This review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (CRD 42021217958).

Isometric handgrip exercise impacts only on very short-term blood pressure variability, but not on short-term blood pressure variability in hypertensive individuals: A randomized controlled trial

Background: The effect of a single isometric handgrip exercise (IHG) on blood pressure (BP) variability (BPV) has not been addressed. This randomized controlled trial evaluated the effect of IHG vs. sham on BPV and BP. Methods: Hypertensive patients using up to two BP-lowering medications were randomly assigned to IHG (4 × 2 min; 30% of maximal voluntary contraction, MVC, with 1 min rest between sets, unilateral) or sham (protocol; 0.3% of MVC). Systolic and diastolic BP were assessed beat-to-beat in the laboratory before, during, and post-intervention and also using 24-h ambulatory BP monitoring (ABPM). BPV was expressed as average real variability (ARV) and standard deviation (SD). Results: Laboratory BPV, ARV and SD variability, had marked increase during the intervention, but not in the sham group, decreasing in the post-intervention recovery period. The overall change in ARV from pre- to 15 min post-intervention were 0.27 ± 0.07 (IHG) vs. 0.05 ± 0.15 (sham group), with a statistically significant p-value for interaction. Similarly, mean systolic BP increased during the intervention (IHG 165.4 ± 4.5 vs. sham 152.4 ± 3.5 mmHg; p = 0.02) as did diastolic BP (104.0 ± 2.5 vs. 90.5 ± 1.7 mmHg, respectively; p < 0.001) and decreased afterward. However, neither the short-term BPV nor BP assessed by ABPM reached statistically significant differences between groups. Conclusion: A single session of IHG reduces very short-term variability but does not affect short-term variability. IHG promotes PEH in the laboratory, but does not sustain 24-h systolic and diastolic PEH beyond the recovery period.

The effect of a single session of isometric handgrip exercise on blood pressure

BACKGROUND: It is unknown whether a session of isometric handgrip (IHG) exercise can influence the blood pressure of hypertensive and normotensive individuals. OBJECTIVE: To compare post exercise hypotension among groups with different resting blood pressure (BP) levels. METHODS: 56 Malay male volunteers (12 normotensive, 14 pre-hypertensive, 19 hypertensive stage 1, and 11 hypertensive stage 2) completed four sets of 2-minute isometric handgrip exercises at 30% of their maximum handgrip contraction with a one-minute break between the sets. Systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP), mean arterial pressure (MAP), resting heart rate (RHR), and handgrip strength (HGS) were measured before and after an hour of IHG exercise. A paired sample t-test, one-way ANOVA, and two-way repeated measure ANCOVA were used to examine the data. RESULTS: All parameters, except RHR and HGS, were significantly changed following the exercise across the BP groups. The SBP, MAP, and HGS were greatly reduced among hypertensive stage 1 (SBP =-6.3 ± 0.6 mmHg; MAP =-4.8 ± 1.1 mmHg; HGS =-6.8 ±-0.4 mmHg) compared to other groups. Meanwhile, the most DBP was reduced among hypertensive stage 2 (mean =-5.2 ± 0.6 mmHg). CONCLUSIONS: The current study discovered a significant reduction in BP among hypertensive stage 1 and 2 individuals after a session of IHG exercise.

Effect of isometric exercise on blood pressure in prehypertensive and hypertensive individuals: protocol for a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Systemic arterial hypertension (HTN) is the leading risk factor of cardiovascular disease death. Lifestyle changes are key for the prevention and management of HTN. Regular aerobic exercise training is recommended as part of the management of HTN, and dynamic resistance exercise should be prescribed as an adjuvant to aerobic training. Recent evidence points to the potential benefits of isometric resistance training in reducing blood pressure (BP). Yet, the hypotensive effect of isometric exercise in prehypertensive and hypertensive individuals is not fully understood. Thus, we will examine the effect of isometric exercise in prehypertensive and hypertensive individuals through a systematic review and meta-analysis.

METHODS

Our systematic review study will include randomized controlled trials (RCTs) selected from the electronic databases MEDLINE (PubMed), Cochrane, LILACS, EMBASE, Web of Science, and PEDro published in English, Spanish, and Portuguese languages. We will follow the PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols) and PICOS framework. Our search will involve studies with both male and female participants aged 18 years or more diagnosed with prehypertension or HTN performing one session of isometric exercise (acute effect) or isometric exercise training (chronic effect) compared to a control group (no exercise). We will use the Cochrane Risk of Bias 2 (RoB 2) tool to evaluate the quality of the studies and RStudio software (v1.3.959 for Windows) for statistical analyses.

DISCUSSION

A meta-analysis of a homogeneous sample of prehypertensive and hypertensive individuals involving isometric handgrip exercise alone can further support previous findings and improve our understanding and recommendations for the management of these populations.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020213081.

Effects of arm-crank exercise on cardiovascular function, functional capacity, cognition and quality of life in patients with peripheral artery disease: Study protocol for a randomized controlled trial

Background

Arm-crank exercise training (ACT) is an alternative exercise strategy for patients with symptomatic peripheral artery disease (PAD) due to the attenuation of pain symptoms during the exercise, as well as the benefits to functional capacity.

Purpose

The aim of this study is to describe the study protocol to analyze the effects of ACT exercise on cardiovascular function, functional capacity, cognition and quality of life in patients with symptomatic PAD.

Methods

This is a three-armed randomized, prospective, single-blind data collection, single-center, controlled study enrolling 45 patients with symptomatic PAD who will be randomized into 3 intervention groups: walking training (WT), ACT and control group. The WT and ACT will perform 2 sessions/week, 15 to 10 sets of 2 to 5 minutes at values of 13 to 15 on the Borg scale. Before and after 12 weeks of intervention, cardiovascular function (ambulatory blood pressure, office blood pressure, central blood pressure, heart rate variability, arterial stiffness and vascular function), functional capacity (six-minute walk test, 2 minute step test, handgrip test, Walking impairment questionnaire, Walking estimated limitation calculated by history, Baltimore activity scale for intermittent claudication, and short physical performance battery), cognition (executive function and memory), and quality of life (vascular quality of life questionnaire and World Health Organization Quality of Life) will be assessed.

Results

This is the first trial to evaluate the effects of ACT on regulatory mechanisms of the cardiovascular system in PAD patients. If the results are as expected, they will provide evidence the ability of ACT to promote cardiovascular benefits in the symptomatic PAD population.

Effects of isometric handgrip exercise with or without blood flow restriction on interference control and feelings

The purpose of this study was to investigate whether isometric handgrip exercise, with or without blood flow restriction, would alter interference control and feelings. 60 healthy young adults completed three experimental visits, consisting of four sets of 2 min isometric handgrip exercise, at 30% of maximal strength with or without blood flow restriction (50% of arterial occlusion pressure), or a non-exercise/time-matched control. Exercise-induced feeling inventory and Stroop Color Word Test were performed at pre- and ~10-min post-exercise, respectively. Bayes factors (BF₁₀ ) quantified the evidence for or against the null. There were no changes or differences between conditions for interference control following exercise with or without blood flow restriction (Incongruent BF₁₀ : 0.155; Stroop Interference BF₁₀ : 0.082). There were also no differences in the error rate as well as no differences between conditions for changes in 'positivity' or 'revitalization'. Feelings of 'tranquility' were reduced relative to a control following exercise with (median δ [95% credible interval]: -0.74 (-1.05, -0.45), BF₁₀ : 5515.7) and without (median δ: -0.72 [-1.02, -0.41], BF₁₀ : 571.3) blood flow restriction. These changes were not different between exercise conditions. Feelings of 'physical exhaustion' were increased relative to a control following exercise without blood flow restriction (median δ: 0.35[0.09, 0.61], BF₁₀ : 5.84). However, this increase was not different from the same exercise with blood flow restriction. These results suggest that 1) isometric handgrip exercise could be performed without impairing interference control, even when blood flow restriction is added, and that 2) changes in feelings occur independent of changes in interference control.

Effects of Isometric Biceps Exercise on Blood Pressure in Adults with Hypertension

We investigated the acute effects of isometric biceps exercise on resting and ambulatory blood pressure in hypertensive adults. A total of 12 medicated hypertensive adults (aged 47±7 years; body mass index 27.2±2.7 kg/m²; resting blood pressure 123±12/74±6 mmHg) performed an isometric biceps exercise session (bilateral biceps exercise; 4×1 min at 30% of 1-RM, 2 min recovery) and a control session (without exercise) in a randomized order separated by a 7 to 10-day period. Resting blood pressure, heart rate, and heart rate variability indexes (SDNN, RMSSD, LF, HF, and LF/HF) were measured pre- and up to 30 min post-sessions. Next, ambulatory blood pressure was monitored during 22-hour post-sessions (awake and asleep periods). No significant changes were observed for resting blood pressure, heart rate, or heart rate variability indexes up to 30 min post-sessions (p>0.05). Furthermore, no significant differences were observed in average ambulatory blood pressure values in 22-hour (126±11/71±6 mmHg vs. 126±15/71±9 mmHg), awake (127±10/74±6 mmHg vs. 130±14/75±10 mmHg), and asleep (123±15/68±6 mmHg vs. 120±17/66±9 mmHg) periods between the control and isometric sessions, respectively (p>0.05). In conclusion, an isometric biceps exercise session does not elicit an acute antihypertensive effect in adults with hypertension, which suggests that its prescription to improve the acute BP control is limited.

Effects of isometric handgrip training on cardiac autonomic profile: A systematic review and meta-analysis study

Meta-analyses have shown that isometric handgrip training reduces blood pressure in normotensive and hypertensive subjects. However, the effects on cardiac autonomic modulation are still controversial. Thus, the aim of this systematic review and meta-analysis was to analyse the effects of isometric handgrip training on cardiac autonomic modulation in normotensive and hypertensive subjects. For this, Medline, Cinhal, Embase, Spordiscus and PEdro were searched for relevant studies published until December 2018. Randomized controlled trials investigating the effect of isometric handgrip training on heart rate variability parameters were considered eligible. Parameters were obtained in time (standard deviation of all the RR intervals-SDNN, root mean square of successive differences between the normal adjacent RR intervals-RMSSD and the percentage of adjacent intervals with more than 50 ms-PNN50) and frequency domain (low frequency-LF, high frequency-HF and sympathovagal balance-LF/HF). Mean difference (MD) and 95% confidence interval (95% CI) were calculated using an inverse variance method with a random effects model. Seven trials were included in the systematic review and meta-analysis, totalling 86 participants. No significant effect was observed in heart rate variability parameters after isometric handgrip training (4 trials to SDNN: MD = -1.44 ms and 95% CI = -8.02, 5.14 ms; RMSSD: MD = -1.48 ms and 95% CI = -9.41, 6.45 ms; PNN50: MD = 0.85% and 95% CI = -1.10, 2.81%; 7 trials to LF: -0.17 n.u. and 95% CI = -6.32, 5.98 n.u.; HF: MD = 0.17 n.u. and 95% CI = -5.97, 6.30 n.u.; and LF/HF: MD = 0.13 and 95% CI = -0.34, 0.59). In conclusion, current literature indicates that isometric handgrip training does not improve heart rate variability.