[Impact of isometric training on blood pressure: an umbrella study of systematic reviews and meta-analyses]

High blood pressure causes 45% of deaths from heart diseases and 51% of deaths from stroke.

OBJECTIVE

To conduct systematic search and summarize the systematic reviews and/or meta-analyses about impact of isometric training on blood pressure.

MATERIAL AND METHODS

Systematic search for publications in PubMed, Cochrane Library and Epistemonikos databases for the period from January of 2017 yr. to 19 of January 2023 yr. was carried out. The search was done by keywords: isometric exercises, isometric training, blood pressure, arterial hypertension, static resistance training, handgrip test. Methodological quality of included articles was assessed using the «Assessment of methodological quality of systematic reviews» (AMSTAR-2) tool. The number of systematic reviews equal 15 was analyzed.

RESULTS

The overall methodological quality of 15 included reviews, obtained by AMSTAR-2, revealed a very low confidence rate (critically low confidence, 10 publications) for results of systematic review and meta-analyses. In total, analysis and generalization of all results of included systematic reviews about blood pressure decrease by isometric training showed, that systolic blood pressure against the background of this method decreases on average by 6.1±2.0 mm Hg, and diastolic blood pressure - by 3.0±1.0 mm Hg.

CONCLUSION

Authors of 15 systemic reviews, included in an umbrella study, reached a common conclusion about isometric training efficacy in secondary prevention of arterial hypertension.

Effect of Isometric Resistance Training on Blood Pressure Values in a Group of Normotensive Participants: A Systematic Review and Meta-analysis

CONTEXT

Cardiovascular diseases cause 17 million deaths annually worldwide, of which hypertension is responsible for 9.4 million and a 7% burden of disease. High blood pressure is responsible for 45% of deaths from heart disease and 51% of deaths from stroke.

OBJECTIVE

The aim of this systematic review and meta-analysis was to quantify the effect of isometric resistance training on systolic, diastolic, and mean arterial blood pressure (SBP, DBP, and MAP, respectively) values in normotensive adult participants.

DATA SOURCES

This study was registered with the PROSPERO database. Eligible studies were identified after performing a systematic search within the following databases: PubMed, Scielo, BioMed Central, Clinical Trials, EMBASE, Cochrane Central Register of Controlled Trials, and EBSCO.

STUDY SELECTION

Randomized controlled trials that categorized participants as normotensive according to the guidelines of the American Heart Association and the American College of Cardiology were included.

STUDY DESIGN

Systematic review with meta-analysis.

LEVEL OF EVIDENCE

Level 1.

DATA EXTRACTION

Data related to participant characteristics, exercise programs, level of evidence, risk of bias, Consensus on Exercise Reporting Template, and outcomes of interest were systematically reviewed independently by 2 authors.

RESULTS

A total of 6 randomized controlled trials were included. The following reductions in blood pressure (compared with the control group) were generated by isometric resistance training: SBP (mean difference [MD], -2.83 mm Hg; 95% CI, -3.95 to -1.72; P < 0.00001), DBP (MD, -2.73; 95% CI, -4.23 to -1.24; P = 0.0003), and MAP (MD, -3.07; 95% CI, -5.24 to -0.90; P = 0.005).

CONCLUSION

It appears that isometric resistance training reduces SBP, DBP, and MAP in normotensive young adults in a statistically significant and clinically relevant manner. This type of exercise could be considered effective in preventing arterial hypertension.

Dynamic, Not Isometric Resistance Training Improves Muscle Inflammation, Oxidative Stress and Hypertrophy in Rats

This study aimed to compare the effects of dynamic (DRT) and isometric (IRT) resistance training on blood glucose, muscle redox capacity, inflammatory state, and muscle strength and hypertrophy. Fifteen 12-week-old male Wistar rats were randomly allocated into three groups: control group (CTL), DRT, and IRT, n = 5 animals per group. The animals were submitted to a maximal weight carried (MWC; every 15 days) and maximum isometric resistance (MIR; pre- and post-training) tests. Both training protocols were performed five times a week during 12 weeks, consisting of one set of eight uninterrupted climbs for 1 min with a 30% overload of MWC. The animals in the IRT group remained under isometry for 1 min. The DRT group experienced greater MWC from pre- to post-training compared to the CTL and IRT groups (p < 0.0001). The DRT and IRT groups displayed similar gains in MIR (p = 0.3658). The DRT group exhibited improved glycemic homeostasis (p = 0.0111), redox (p < 0.0001), and inflammatory (p < 0.0001) balance as compared with CTL and IRT groups. In addition, the improved glycemic profile was associated with an increase in muscle strength and hypertrophy, improvement in redox balance and inflammation status. We conclude that DRT was more effective than IRT on increasing cross-sectional area, but not muscle strength, in parallel to improved blood glucose, inflammatory status, and redox balance.