Isometric Resistance Training and Dose-dependent Effects in Pre- and Hypertensive Adults

The University of Northampton

Status and phase: Completed; Phase 3

Conditions: Blood Pressure, High; Hypertension

Treatments: Other: Isometric resistance training

Study type: Interventional

Funder types: Other

Identifiers

NCT07251920

FREC2324002

Details and patient eligibility

About

High blood pressure is prevalent in a third of the global population and is a key risk factor for cardiovascular disease, the leading cause of death. one lifestyle change that is recommended to reduce blood pressure is to exercise, typically by performing aerobic exercise, but this is often not well adhered to, given the physical and time demands associated with it. Isometric resistance training has been evidenced as an efficacious method to reduce blood pressure, even when performing four two-minute contractions per day, three days per week at 30% of maximum effort. At present, the dose-response effects have not been examined, which are required to identify the minimal effective dose, which could further reduce the temporal demands of this modality to potentially enhance adhernece even more in time-anxious individuals. Therefore, this study aimed to compare the efficacy of once- twice-, and thrice-weekly isometric resistance training programmes to lower blood pressure,

Full description

The World Health Organisation have reported hypertension, a major risk factor for cardiovascular disease (CVD), strokes and coronary heart disease (CHD), to be near epidemic levels globally with over 30% of the world's population, at this time, suffering from hypertension. Over the past twenty years isometric resistance training (IRT) has been established as one of the best forms of nonpharmacological interventions for the prevention and treatment of hypertension and endorsed by the American College of Cardiology / American Heart Association in their most recent guidelines. Thrice weekly IRT programmes undertaken (4 x 2-minute isometric contractions) at 20-30% of an individual's maximum voluntary contraction (MVC) for a period of 4-10 weeks have demonstrated reductions in clinic resting and ambulatory systolic blood pressure (-4 to -10 mmHg), in both normotensive and hypertensive men and women with no reported difference in the magnitude of these reductions between women and men.

Whilst isometric training has been shown to produce clinically meaningful reductions in blood pressure, utilising the commonly used protocol (4 x 2-min contractions) three-times a week, one of the main barriers to therapeutic exercise interventions is time to undertake the intervention and despite the observed benefits, adherence and compliance tends to be low. Indeed, regular exercise adherence declines over time, with only 50% of individuals continuing with regular exercise within the first twelve months following the completion of a therapeutic treatment, with a lack of perceived time cited as one of the main barriers. With this in mind, it is important to determine the effects of training dose on the changes in blood pressure seen following IRT. To date there is very little research into the effects of IRT dose on resting blood pressure with only one study purposely investigated the area. Whilst to the authors knowledge no studies have investigated the effects of altered training dose on ambulatory or diurnal blood pressure variations. Although three times a week has become the most commonly applied protocol there is no evidence to confirm that it is the most efficacious. As training dose is an important determinant of adaptations to exercise training, and with a lack of time cited as a perceived barrier to undertaking exercise, there is a need to determine the most efficacious training protocol to elicit clinical reductions in blood pressure, including shorter time saving (once or twice weekly) protocols.

Therefore, the study aims are to determine if a reduction in the weekly dose of isometric training, such as a reduction in the number of total contractions and therefore a reduced time commitment (once or twice weekly) would produce a similar hypotensive response to those reported.

Enrollment: 30 patients

Sex: All

Ages: 18 to 60 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• not taking anti-hypertensive medication
• borderlerine hypertensive or hypertensive (systolic blood pressure >139 mmHG, diastolic blood pressure > 89 mmHg

Exclusion criteria

• conditoned to resistance training
• currently taking anti-hypertensive medication
• regularly smoke or vape
• are pregnant

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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30 participants in 3 patient groups

Once-weekly training

Experimental group

Description:

Performed isometric resistance training once per week (four 2-minute contractions).

Treatment:

Other: Isometric resistance training

Twice-weekly training

Experimental group

Description:

Performed isometric resistance training twice per week (eight 2-minute contractions).

Treatment:

Other: Isometric resistance training

Thrice-weekly training

Active Comparator group

Description:

Performed isometric resistance training thrice per week (12 2-minute contractions).

Treatment:

Other: Isometric resistance training