Blood Pressure Following Isometric Exercise in Inactive Adults

Conditions studied

Hypertension, Elevated Blood Pressure, Sedentary Lifestlye

About this study

This study investigates how isometric exercise training (IET) affects blood pressure in physically inactive adults. Isometric exercise involves sustained muscle contractions without movement-for example, pushing against a fixed object. Previous research has shown that IET may help reduce blood pressure, but the mechanisms involved are not fully understood. The purpose of this study is to assess both the immediate (acute) and long-term (chronic) effects of IET on cardiovascular outcomes. Participants will complete a series of lab-based exercise sessions over several weeks. In these sessions, they will perform repeated bouts of isometric leg extensions while seated on an exercise machine designed to measure muscle force. Throughout the study, researchers will monitor participants' blood pressure, heart rate, and muscle activity. Acute responses-such as post-exercise hypotension (a short-term drop in blood pressure)-will be measured immediately after exercise. Chronic changes, such as resting blood pressure improvements, will be evaluated across the training period. Additional measurements will include heart rate variability (HRV), which gives insight into autonomic nervous system activity, and electromyography (EMG), which tracks muscle fatigue and activation patterns. These data will help explore potential mechanisms behind the cardiovascular benefits of IET. By examining how repeated sessions of isometric exercise influence blood pressure and related physiological responses, this research may support the use of IET as a non-pharmacological strategy for managing or preventing hypertension in physically inactive individuals.

Interventions

• Behavioral: Isometric Exercise Training (IET) — Participants perform four repetitions of 90 degree bilateral isometric leg extensions on a dynamometer at 30% of their maximum voluntary contraction (MVC). Each contraction is held for 2 minutes, with 2-minute rest intervals between bouts. Sessions are performed three times per week for four weeks. This behavioral intervention is designed to investigate the acute and chronic effects of isometric exercise on blood pressure, heart rate variability, and muscle fatigue.
• Behavioral: Expectation-Enhancing Informational Framing — Participants receive a brief standardized presentation highlighting isometric exercise as an evidence-based intervention for lowering blood pressure. The presentation includes statements designed to enhance outcome expectations based on prior literature and expert framing.

Primary outcomes

• Change in Resting Systolic Blood Pressure (Baseline to Post-Intervention (approximately 4 weeks))

Eligibility information

Study locations

• Canterbury Christ Church University, Canterbury, Kent CT1 1QU United Kingdom