Acute effects of breaking up sitting time with isometric wall squat exercise on vascular function and blood pressure in sedentary adults: Randomized crossover trial

Purpose: The World Health Organization has recommended breaking up sitting time to improve cardiovascular health. However, whether isometric exercise can be effectively used as a strategy to break up sitting time remains unclear. Thus, the aim of this study was to analyze the acute effects of breaking up prolonged sitting with isometric wall squat exercise on vascular function and blood pressure in sedentary adults. Methods: This randomized crossover trial included 17 adults (52.9% men, 26±6 yrs, 22.4±3.6 kg/m2) with high sedentary behavior (≥ 6h per day). The participants completed two experimental sessions in a randomized order, both sharing a common sitting period of 180 minutes: Breaks (two-minute breaks were incorporated into the isometric wall squat exercise, with participants maintaining their knees at the angle determined by the incremental test, which occurred every 30 minutes) and Control (sitting for 180 minutes continuously). Popliteal artery flow-mediated dilation (FMD) and brachial blood pressure were measured before, at 10 and 30 minutes after the experimental sessions. Results: The results did not indicate significant session vs. time interaction effects on popliteal FMD and brachial blood pressure (p>0.05). A sub-analysis including only participants with popliteal FMD reduction after the Control session (n=11), revealed that Breaks enhanced popliteal FMD after 10 minutes (1.38±6.45 % vs. -4.87±2.95 %, p=.002) and 30 minutes (-0.43±2.48 % vs. -2.11±5.22 %, p=.047). Conclusion: breaking up prolonged sitting with isometric wall squat exercise mitigates impaired vascular function resulting from prolonged sitting but has no effect on blood pressure in sedentary adults

Characteristics associated with responsiveness to isometric handgrip training in medicated hypertensives: Secondary data anaylysis

Objective: Isometric handgrip training (IHT) has been shown to reduce blood pressure (BP) in hypertensives. However, factors that predict responsiveness to IHT are largely unknown. The aim of this study was to investigate the patient characteristics associated with the anti-hypertensive response to IHT using a recommended statistical approach for evaluating interindividual responses. Methods: Data from four randomized controlled trials were joined, totaling 81 patients undergoing IHT (48.8% women; 60±11 yr) and 90 control patients (45.6% women; 62±12 yr). IHT consisted of 4x2-minute 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 (SDir), and linear regression analyses were conducted to explore response predictors. Results: IHT significantly decreased both systolic (-5.4; 95%CI: -9.5 to -1.3 mmHg) and diastolic (-2.8; 95%CI: -5.1 to -0.6 mmHg) BPs. The interindividual variation of BP change was moderate for systolic (SDir=5.2 mmHg, 0.30 standardized units) and low for diastolic (SDir=1.7 mmHg, 0.15 standardized units). Sex, age, and body mass index were not associated with the anti-hypertensive effect of IHT. However, a higher baseline systolic BP (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 systolic BP 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 centered 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 under utilised 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