Effects of isometric handgrip training on blood pressure among hypertensive patients seen within public primary healthcare: a randomized controlled trial

Characteristics associated with responsiveness to isometric handgrip training in medicated hypertensive patients: secondary data analysis

OBJECTIVE

Isometric handgrip training (IHT) has been shown to reduce blood pressure (BP) in hypertensive patients. However, factors that predict responsiveness to IHT are largely unknown. The aim of this study was to investigate the patient characteristics associated with the antihypertensive response to IHT using a recommended statistical approach for evaluating interindividual responses.

METHODS

Data from four randomized controlled trials were combined, totaling 81 patients undergoing IHT (48.8% women; 60 ± 11 years) and 90 control patients (45.6% women; 62 ± 12 years). IHT consisted of 4 × 2 min isometric contractions at 30% of maximal voluntary contraction, performed three times/week for 8-12 weeks. BP was measured at baseline and following IHT and control interventions. The interindividual variation was assessed by the standard deviation of the individual responses (SD ir ), and linear regression analyses were conducted to explore response predictors.

RESULTS

IHT significantly decreased both SBP (-5.4; 95% confidence interval (CI) -9.5 to -1.3 mmHg) and DBP (-2.8; 95% CI -5.1 to -0.6 mmHg). The interindividual variation of BP change was moderate for systolic (SD ir  = 5.2 mmHg, 0.30 standardized units) and low for diastolic (SD ir  = 1.7 mmHg, 0.15 standardized units). Sex, age, and BMI were not associated with the antihypertensive effect of IHT. However, a higher baseline SBP ( b  = -0.467, P  < 0.001) and absence of dihydropyridine calcium channel blockers use ( b  = 0.340, P  = 0.001) were associated with greater BP reductions.

CONCLUSION

IHT reduced BP in medicated hypertensive patients regardless of age, sex, and BMI. Patients with a higher baseline SBP and those not prescribed dihydropyridine calcium channel blockers were more responsive to IHT.

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 Resistance Training to Manage Hypertension: Systematic Review and Meta-analysis

PURPOSE OF REVIEW

Hypertension is the primary risk factor for cardiovascular disease and adequate blood pressure control is often elusive. The objective of this work was to conduct a meta-analysis of trial data of isometric resistance training (IRT) studies in people with hypertension, to establish if IRT produced an anti-hypertensive effect. A database search (PubMed, CINAHL, Cochrane Central Register of Controlled Trials, and MEDLINE) identified randomised controlled and crossover trials of IRT versus a sedentary or sham control group in adults with hypertension.

RECENT FINDINGS

We included 12 studies (14 intervention groups) in the meta-analyses, with an aggregate of 415 participants. IRT reduced systolic blood pressure (SBP), mean difference (MD) - 7.47 mmHg (95%CI - 10.10, - 4.84), P < 0.01; diastolic blood pressure (DBP) MD - 3.17 mmHg (95%CI - 5.29, - 1.04), P < 0.01; and mean arterial blood pressure (MAP) MD - 7.19 mmHg (95%CI - 9.06, - 5.32), P < 0.0001. Office pulse pressure and resting heart rate was not significantly reduced, neither were 24-h or day-time ambulatory blood pressures (SBP, DBP). Night-time blood pressures, however, were significantly reduced with SBP MD - 4.28 mmHg (95%CI - 7.88, - 0.67), P = 0.02, and DBP MD - 2.22 mmHg (95%CI - 3.55, - 0.88), P < 0.01. IRT does lower SBP, DBP and MAP office and night-time ambulatory SBP and DBP, but not 24-h mean ambulatory blood pressures in people with hypertension.

Reductions in systolic blood pressure achieved by hypertensives with three isometric training sessions per week are maintained with a single session per week

Isometric handgrip or (wall) squat exercise performed three times per week produces reductions in systolic blood pressure (SBP) in adults with hypertension. We aimed to compare these interventions and the potential to retain benefits with one exercise session per week. We compared blood pressure changes following handgrip and squat isometric training interventions with controls in a randomized controlled multicentre trial in 77 unmedicated hypertensive (SBP ≥ 130 mmHg) adults. Exercise sessions were performed in the workplace and consisted of four repetitions-three sessions per week for the first 12 weeks (phase 1), and one session per week for the subsequent 12 weeks (phase 2). Office blood pressure (BP) was measured at baseline, post-phase 1 and post-phase 2. Post-phase 1, mean reductions in SBP were significantly greater in handgrip (-11.2 mmHg, n = 28) and squat (-12.9 mmHg, n = 27) groups than in controls (-.4 mmHg; n = 22) but changes in DBP were not. There were no significant within-group changes during phase 2 but SBP was 3.8 mmHg lower in the wall squat than the handgrip group-a small magnitude but clinically important difference. While both interventions produced significant SBP reductions, the wall squat appears to be more effective in maintaining benefits with a minimal training dose. The low time investment to achieve and retain clinically significant SBP reductions-42 and 12 min, respectively-and minimal cost, particularly of the wall squat, make it a promising intervention for delivery in public health settings.