The effects of isometric exercise on resting blood pressure: a home-based approach

The main focus of this thesis was to develop an accessible home-based isometric exercise training (IET) protocol for the reduction of resting blood pressure (BP). Hypertension is estimated to affect nearly 30% of the world’s population (WHO, 2012) and represents an inordinate health and economic burden worldwide. A growing body of research suggests that IET can lower resting BP. However, the majority of studies have utilised expensive and/or laboratory-based equipment, which may not be accessible to the general population. To this end, the studies within this thesis explored whether the novel isometric wall squat exercise could be prescribed for home-based training using relatively simple, inexpensive equipment. The first study determined a method for adjusting the wall squat intensity. It was found that knee joint angle reliably produced inverse relationships with heart rate (HR) and BP when individual bouts of wall squat exercise were completed (r at least -0.80; P < 0.05). Study 2 then established that these inverse relationships could be replicated from completing an incremental test (r at least -0.88; P < 0.05), from which wall squat training intensity could then be prescribed at an individualised knee joint angle (104 ± 7°) to elicit a target training HR (95% peak HR: 121 ± 14 beats∙min-1). Finally, using these methods, study 3 implemented a 4 week home-based isometric wall squat training protocol and found statistically significant and clinically relevant resting BP reductions (systolic BP: -4 mmHg; diastolic BP -3 mmHg; mean arterial pressure: -3 mmHg). These results support the majority of previous research that has found reductions in resting BP following IET. Furthermore, the primary BP control mechanisms were also explored and the results suggested that a reduction in resting BP was potentially mediated by a decrease in resting cardiac output (-0.54 ± 0.66 L∙min-1), which may have been governed by a reduction in resting HR (-5 ± 7 beats∙min-1). The novel home-based IET protocol developed within this thesis may be more time and cost effective, which may ultimately increase the adherence to and efficacy of IET for
the reduction of resting BP.